Electronics - American Radio History

Electronics - American Radio History

Popular Electronics® WORLD'S LARGEST SELLING ELECTRONICS MAGAZINE JULY 1982/$1.25 Simple Audio Gate Reduces Noise An EPROM Programmer for Small Co...

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By holding a slim plastic "magic wand" radio close to her ear, the young lassie at left -as well as other visitors -can

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Popular

Electronics®

WORLD'S LARGEST SELLING ELECTRONICS MAGAZINE

JULY 1982/$1.25

Simple Audio Gate Reduces Noise An EPROM Programmer for Small Computers Scope Swch Provides Multi-Channel Traces FORREST MIMS COMPARES

The New Handheld Computers

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in this Issue.

Right away, you can see a difference.

Stop in a store near you. Take a look. You'll be instantly taken with some of the features that make the IBM Personal Computer so different. Like the non -glare screen easy on the eyes during those number-crunching tasks like payroll and general ledger. 80 characters a line -with upper and lower case letters for a quick and easy read. And the flexibility of a system that lets you move the components around at will. (To get really comfortable, try the keyboard on your lap and put your feet up.)

-

There's more than meets the eye. Some of the best things about the IBM Personal Computer aren't part of the computer. Like the instruction manuals that help you set up your system and teach you to use

it with the greatest of ease. IBM PERSONAL COMPUTER SPECIFICATIONS Display Screen High -resolution'

Permanent Memory

Microprocessor

80 characters x 25 lines

16-hit,

Upper and lower case Green phosphor screen`

Color/Graphics

User Memory 16K -256K

bytes'

8088"

Auxiliary Memory 2

optional internal diskette drives,

Operating Systems DOS, UCSD p- System, CP/M -86t

31/4",160K bytes

per diskette

Go

languages

Keyboard

ahead, compare.

As you progress from casual observer to comparison shopper,

you'll want the inside story of the IBM Personal Computer. Like user memory expandable up to 256KB. And 40KB of permanent memory. (Which not only includes the BASIC language, but diagnostic instructions that automatically check the system every time you turn it on.) A 16 -bit microprocessor that can improve speed and productivity. A mix of crisp text and high resolution color graphics on your own TV set- clearly helpful for creating charts to target forecasts and trends. Or the 10 programmable function keys that let you bid goodbye to the tedium of repetitious tasks. And the list goes on. Which is why we've included a box (at right) that tells all.

a

trademark of the Regents of the University of California. CP /M-86 CIRCLE NO.

2

is a

Test mode: 16 colors'

256 characters and

symbols in ROM' Graphics mode 4-color resolution: 320h x 200v* Black & white resolution: 640h x 200v* Simultaneous graphics & text capability

83 keys, 6 ft cord attaches to system unit'

BASIC, Pascal, FOR'T'RAN, MACRO Assembler,

10 function

keys* 10-key numeric pad

Printer

Tactile feedback

Bidirectional'

Communications

Diagnostics

80 characters /second 12 character styles, up to

Power -on self testing` Parity checking'

9 x 9 character matrix'

RS -232 -C interface Asynchronous (start/stop) protocol Up to 9600 hits per second

COBOL

132

characters/line*

'ADVANCED FEATURES FOR PERSONAL COMPUTERS

And an expanding library of software programs that meet IBM's demanding specifications. Programs for business. Education. The lab and the home. Programs that make the IBM Personal Computer your tool for modern times. See for yourself.

The quality, power and performance of the IBM Personal Computer are what you'd expect from IBM. The price isn't. So stop in and take a look. Visit an authorized IBM Personal Computer dealer. For a store near you, (or for information from IBM about quantity purchases) call (800) 447 -4700. In Illinois, (800) 322-4400. In Alaska or Hawaii, (800) 447 -0890.

==

The IBM Personal Computer A tool for modern times tLJCSD p- System is

(ROM) 40K bytes'

trademark of Digital Research, Inc.

ON FREE INFORMATION CARD

WHY K40

BECAME THE LARGEST SELLING CB ANTENNA IN JUST ONE YEAR!

VOLUME 20, NUMBER 7

JULY 1982

Popular Electronics® WORLD'S LARGEST- SELLING ELECTRONICS MAGAZINE

Feature Articles 38

PE COMPARES NEW HANDHELD COMPUTERS/Forrest M. Mims

Results of "hands on experience with Sharp, Quasar, and H -P handhelds.

85

ENGLISH BROADCASTS AUDIBLE IN NORTH AMERICA /Glenn Hauser

Construction Articles 49

SIMPLE AUDIO GATE EXPANDS DYNAMIC RANGE /John H. Davis Obtain effective noise reduction with inexpensive circuit.

Vezeta

4 -TRACE

57

PROGRAMMING EPROMs WITH A SMALL COMPUTER /J.Doolittle and S. Tkalcevic Expand your digital design work with a modest-cost peripheral.

61

BUILD A TOUCH- CONTROLLED SOLID -STATE SWITCH/Ken Raich Device can be used for TTL or MOS.

66

CONVERTER FOR OSCILLOSCOPES /Jim Morgan Convert your single-trace instrument into a multi- channel oscilloscope.

OFFERS A

__MONEY BACK DOUBLE GUARANTEE

TRANSMITS FARTHER RECEIVES CLEARER ...THAN ANY ANTENNA IT REPLACES!

Ame:1441:0

Wee' 0U t.ETCHA!

... WHILE YOU TALK /Paul Danzer Measure SWR without interrupting SSB transmission or recalibrating.

CHECK YOUR SWR

69

Equipment Reviews SHURE MODEL V15 TYPE V PHONO CARTRIDGE

17

SANYO MODEL 91C85 19" COLOR TV RECEIVER

20 28 67

SYSTEMS GROUP MODEL 2829 MICROCOMPUTER FOX MODEL BMP -10/60 SCANNER RECEIVER

Columns ENTERTAINMENT ELECTRONICS /Len Feldman The AM Stereo Situation.

14

SOLID -STATE DEVELOPMENTS/Forrest M. Mims

73

New Piezoelectric Products. COMPUTER BITS /Carl Warren Add -Ins and Add-Ons Increase System Performance.

75

COMPUTER SOURCES /Leslie Solomon

78

PROGRAMMER'S NOTEBOOK /Jim Keogh Keeping Time.

79

EXPERIMENTER'S CORNER /Forrest M. Mims Experimenting with Piezoelectric Devices. Part 1. Microphones, Pushbuttons, and Ceramic Filters.

82

PROJECT OF THE MONTH /Forrest M. Mims A Fully Adjustable Pulse Generator.

90

Departments EDITORIAL /Art Salsberg Down With QWERTY.

4

LETTERS

6 6 8

OUT OF TUNE NEW PRODUCTS

ADVERTISER'S INDEX PERSONAL ELECTRONIC NEWS

89 108

COVER GRAPHICS BY JACK WARD COLOR SERVICES INC.

AN AMERICAN MADE PRODUCT FROM AN AMERICAN COMPANY.

Call your local CB Dealer Yello

Pages

For a FREE demo! AN1FRIC'AN , \.\7TI ìNNA

© Copyright

1979 American Antenna Elgin, Ilknois

CIRCLE NO. 2

B

COPYRIGHT 1982 BY ZIFF -DAVIS PUBLISHING COMPANY. All rights reserved. Popular Electronics (ISSN 0032 -4485) July 1982, Volume 20. Number 7. Published monthly by Ziff -Davis Publishing Co.. at One Park Ave., New York, NY 10016. Richard P. Friese. President; Selwyn Taubman, Treasurer; Bertram A. Abrams, Secretary. One year subscription rate for U.S. and Possessions, $15.00; Canada, $20.00; all other countries, $23.00 (cash orders only, payable in U.S. currency). Second Class Postage Paid at New York, N.Y. 10016 and at additional mailing offices. Authorized as second class mail by the Post Office Dept., Ottawa, Canada, and for payment of postage in cash. POPULAR ELECTRONICS including ELECTRONICS WORLD, Trade Mark Registered. Indexed in the Reader's Guide to Periodical Literature. Ziff -Davis also publishes Boating, Car and Driver, Cycle. Flying, Popular Photography, Skiing, Stereo Review, Electronic Experimenter's Handbook, and Tape Recording 8 Buying Guide. POSTMASTER: Send address changes to POPULAR ELECTRONICS. Circulation Dept. P.O. Box 2774, Boulder, CO 80302. Please allow at least eight weeks for change of address. enclosing, if possible, an address label from a recent issue. Permissions. Material in this publication may not be reproduced in any form without permission. Requests for permission should be directed to John Babcock, Rights and Permissions, Ziff -Davis Publishing Co., One Park Ave., New York, NY 10016.

ON FREE INFORMATION CARD

POPULAR ELECTRONICS

Someday, in the comfort of your hone, you' be c ole to shoo c ml bank electronically, reac instantly updcted newswires, cnalyzc the perfornc nce of a stock that interests you, send electronic mail across the coon -ry, then p cy Bridge wig nree strangers in LA,

Chiccgo cnd Dal cs,

Welcome to someday. Someday Is today with the CompuServe Information Service. CompuServe is available through a local phone call in most major U S. cities. It connects almost any brand or type of personal computer or terminal with our big mainframe computers and data bases. All you need to get started is an inexpensive telephone coupler and easy -to -use software. CompuServe is basic service costs only $5.00 per hour, billed in minute increments to your charge card. The CompuServe Information Service is available at many computer stores across the country. Check with your favorite computer center or contact CompuServe. Welcome to someday.

CompuServe Information Service Division, 5000 Arlington Centre Blvc. Columbus, Ohio 43220 (614) 457 -8650 An

H &R

Block Company

CIRCLE NO. 13 ON FREE INFORMATION CARD

Down With QWERTY I'm a fairly fast touch -typist. But, then, my motivation for achieving this status was stronger than for most people: "Type more than 40 words -per- minute after deducting for errors and you'll go to EUCOM (European Command); otherwise, it's likely to be FECOM (Far East Command during the Korean War)." The typewriter system I learned in the U.S. Army was developed when Abraham Lincoln was President of the United States. By the turn of the century, this QWERTY keyboard (named for the sequence of the first six characters on the first line of a typewriter's letter keys) was entrenched in our society. It's omnipresent today. This strange placement of keys was developed to overcome mechanical difficulties. The inventor, Christopher Sholes, placed the most -often -used letters as far apart as possible to prevent jamming of keys as each key arm moved toward one central ribbon- striking opening. Notwithstanding this design, super speed typists still encounter an occasional jamming problem with a conventional keyboard mechanism. This problem was eliminated by use of a typewriter font ball made popu-

Popular Electronics

lar by IBM. Now manual -input keyboards have evolved into non -ribbon electrical types for use with computers. These are the wiping contact and capacitance- change designs that don't use moving parts to strike a ribbon; output is displayed on a video screen, while hard copy is produced on a printer without a keyboard through impulses fed to it by electrical signals from a computer. Without moving parts to jam, why do we need the QWERTY system, whose random placement of letters invites inefficient finger motions as they stroke the keys? Clearly, we do not! Not if we want information input to be speeded up, that is, as the high -speed computer age envelops us. Other typing systems have been examined for generations now, with at least one, the Dvorak or DSK keyboard, deemed to significantly improve typing speed and reduce fatigue. The DSK system places vowels (A, E, I, O, U) as the leading consecutively placed keys. A more recent keyboard development uses a wipe-activated design in which a "wand" is employed instead of fingers. Here, letters are arranged so that some of them form

commonly used words. For example, A N D letters are sequential, as are WITH E, which form five words. Whichever system is finally adopted to replace the archaic QWERTY, we had better move toward it with dispatch. If we don't, the full impact of having computers and peripheral equipment that operate at lightning speed will be wasted owing to slow manual inputting. For those of you who might counter this urgent need by pointing out the development of voice -recognition equipment, I say, don't bet on it within the next generation or two for widespread use with all the words in a dictionary.

Editorial and Executive Offices

Ziff-Davis

One Park Avenue

New York, New York 10016 212 725 -3500

JOE MESICS Publisher

ARTHUR P. SALSBERO Editorial Director

DONALD MENNIE Executive Editor

LESLIE SOLOMON Technical Director

JOHN R. RIGGS Managing Editor

EDWARD L BUXBAUM Art Director

JOSEPH DESPOSITO Technical Editor

DAVID M. WEBER Features Editor

ANDRE DUZANT Technical Illustrator

CARMEN ROBLES Production Editor

JEFF NEWMAN

Publisher Joe E. Mesics 212 725 -3568

New York Office

Advertising Director: Richard Govatski 212 725 -7460 Sales:

Tom Ballon 212 725 -3578 Ken Lipka 212 725 -3580

Midwestern Office Suite 1400, 180 N. Michigan Ave., Chicago, IL 60601 312 346 -2600 Sales: Ted Welch Western Representative Norman S. Schindler & Associates, Inc. 7050 Owensmouth Ave., #209 Canoga Park, CA 91303 213 999 -1414 Sales: Norm Schindler

Lai Publishing Company President Richard P. Friese President, Consumer Albert S. Traîna Magazine Division Furman Hebb Executive Vice President Senior Vice Presidents Phillip T. Heffernan Sidney Holtz Edward D. Muhlfeld

Philip Sine Vice Presidents

Robert Bavier Baird Davis George Morrissey Selwyn Taubman Bertram A. Abrams

Treasurer Secretary

Editorial correspondence: POPULAR ELECTRONI Park Ave., New York, NY 10016. Editorial contributions must be accompanied by return postage and will be handled with reasonable care; however, publisher assumes no responsibility for return or safety of manuscripts, art work, or models submitted. ICS,

The publisher has no knowledge of any proprietary rights which will be violated by the making or using of any items disclosed in this issue.

Editorial Assistant Contributing Editors:

Walter Buchsbaum, Len Feldman, Glenn Hauser, Julian Hirsch Jim Keogh, Forrest Mims, Carl Warren MARIE MAESTRI

Representation in Japan J.S. Yagi

Iwai Trading Co., Ltd. 603 Ginza Sky Heights Bldg. 18 -13, Ginza 7 -Chome Tokyo, Japan 104

Member Audit Bureau of C,rculations

444D

Executis Jv ntruu

4

POPULAR ELECTRONICS

TEK

THE PERFORMANCE/ PRICE STANDARD

DUAL TRACE OSCILLOSCOPES

The $1100 scope. Only Tektronix could make so much performance so affordable! The 60 MHz Tek 2213 and 2215 introduce a scope

design so radically different, it delivers full range performance at prices well below what was ever possible before. Not surprisingly, it is from Tektronix, the world's largest and most respected scope manufacturer, and a legend for instrument reliability and value.

Design for the 2213 ($1100) and dual time base 2215 (just $1400) includes some 65% fewer mechanical parts. Fewer circuit boards. Fewer electrical connectors and cabling. Result: a lower purchase price for you plus far greater reliability.

Performance is pure Tektronix: there's the

bandwidth for digital and high -speed analog circuits. The sensitivity for low signal measurements. The sweep speeds for fast logic families A complete trigger system for digital, analog or video waveforms. And, with the 2215, you get fully calibrated delayed sweep for fast accurate timing measurements. New high= performance 10X Tektronix probes are included!

to 2 mV /div (1X probe). Accurate to ± 3 %. Ac or dc

coupling. Delayed sweep measurements: 2213: standard sweep, intensified after delay, and delayed. 2215: A only, B only, or A and B alternately with A intensified by B.

Complete trigger system:

Sweep speeds: Sweeps

Modes include TV field. normal, vertical mode. and automatic; internal, external, and line sources; variable holdoff; separate B sweep trigger on 2215. Probes: High performance, positive attachment 10-14 pF and 60 MHz at the probe tip.

from 0.5 s to 50 ns (to 5 ns /div with X10 mag). Sensitivity: Scale factors from 100 V /div (10X probe)

The price: Just $1100 for the 2213 and $1400 for the dual time base 2215*. Order direct from the

2213/2215 PERFORMANCE DATA Bandwidth: Two channels, dc-60 MHz from 10 V/div to 20 mV/div. (50 MHz from 2 mV /div to 10 mV /div).

'Prices FOB Beaverton. OR

,

Tektronix National Marketing Center, your hotline for the 2200 Series and all Tektronix accessories. Phones are staffed by sales engineers who can answer your technical questions. Your direct order includes a 15 -day return

policy and

full Tektronix warranty. Call today. You can't buy a more advanced scope for less.

ORDER TOLL FREE

800 - 547 -1845 Ask for Department D0226 (In Oregon, Alaska and

Hawaii: 1- 503-627-5402 collect.) Lines are open from 8 am EST to 5 pm PST

Téktronbc COMMITTED TO EXCELLENCE

Copyright © 1982 Tektronix. Inc.

All rights reserved. 120

Put your ideas in our box.

housed in our attractive, high impact case (4 "H x 10 "W x 7 "D). complete with aluminum front panel and hardware. Priced from just $149.95.` The Idea Box has the capacity for big ideas as well as small ones. You can stack any of the three circuit cards, in any combination. So, before you tackle your next project, get a head start with a little help from us: have an Idea Box on hand. After all, good ideas shouldn't be kept waiting.

Meet the Idea Box. The shortest distance between idea and working prototype or one -of -akind instrument. It's a great time -saver! You design the circuit, we provide the power supplies...assembled and tested...and the right case to house it all. The Idea Box comes complete with three highly regulated low- ripple power supplies (fixed 5VDC @ 1A; + and 15VDC, variable, @0.5A). Pus yourchoice of a solderless breadboard; a pre etched, pre -drilled PCB which emulates the hole connection of the solderless breadboard's pattern; or a blank foil board you can use for existing PCB designs. All,

LEJ1ERS Waveform Credit

The sidebar on digital storage that accompanied "Add Waveform Storage to Your Oscilloscope" in the April 1982 issue has some information that appears in the Tektronix "The Digital Storage Oscilloscope" primer. It was not credited as such, however. -Pam Edstrom, Public Relations Supervisor, Tektronix, Inc., Beaverton, OR.

Thanks for calling the oversight to our attention. Credit for using some information from this fine primer is herewith

issued.-Ed.

Fantastic Help

Your magazine is really fantastic in the help it gives me in applying electronics to my computer hobby. I really appreciate articles like the one on the r -f modulator in the February issue ( "One -Chip R-F Modulator for Crisp Color Sig nals").-H.R. Brown, Spirit River, Alberta, Can. Lower -Case on Model III

Your review of the Radio Shack TRSIII Computer was very interesting but one point should be clarified. The author stated that lower case letters could not be directly accessed in Scripsit. This is easily done using Control- Shift. I have been using this word -processing program for reports, spec drawings, and correspondence and it meets all my needs with ease and style. -W. Barbier, Hazel80 Model

wood, MO.

With regard to the availability of lower -case with the Scripsit program on the TRS -80 Model III, I use the "bare bones" Scripsit and find that "shift -O" gets me into lower case and back with no difficulty. -A. Kohlber, Jr., New Carrollton, MD. Out of Tune

GLOBAL SPECIALTIES CORPORATION OTHER OFFICES

70 Fulto,1 Terr. New Haven, CT 06509 (203) 624.3103. TWO 710-465 -1227 San Francisco (415) 648 -0611. TWX 910- 372 -7992 Europe Phone Saffron -Walden 0799 -21682 TLX 817477 Canada. Len Finkler Ltd Downswew. Ontario .

Call toll -free for details 1- 800 -243 -6077 During business hours

*Suggested U.S. resale. Prices. specifications subject to change without notice. © Copyright 1981 Global Specialties Corporation.

CIRCLE NO. 21 ON FREE INFORMATION CARD 6

In "Digital Automotive Tune-Up Meter" (May 1982), in Fig. 4, the C9 shown in the upper part of Fig. 4 should be Cl. It is shown on both sides of the board because it can be mounted on either side, depending on its size. In the same article, the plug marked ACC on the front panel and shown in the photo, is not used in

this project. In "Experimenting with Fiber Optics" (May 1982), in Fig. 2, the emitters of the two output transistors should be connected together to ground and the collector of the bottom transistor should go to RI, not to ground. In "Build a Synchronous Detector for AM Radio" (April 1982), in Fig. 4, pin 3 of IC8 should be connected to pin 11 of IC2 not pin 10. POPULAR ELECTRONICS

Build your own computer for $79 95

fir;

The Sinclair ZX81 personal computer kit Imagine building your own computer for only $79.95! That's exactly what you can do with the ZX81 kit. It comes with all the parts you need and complete diagrams and instructions for putting it together. All you have to supply is soldering iron, solder, and a screwdriver. Plus, of course, a little bit of work. But you get a lot more than several hours of kit -building fun. You also get a surprisingly powerful personal computer. The ZX81 hooks up to any TV for a 32character by 24 -line display (we provide the connecting cables). You can also use a standard cassette recorder to store your programs (again, we provide the cables). Most important, you get a BASIC programming language that's powerful enough to challenge and interest the most experienced programmers. The ZX81 can handle multidimensional string and numerical arrays. It has full mathematical functions accurate to eight decimal places. Single-key entry for every command. Syntax error detection, debugging codes, and easy editing. Plus features that are ideal for creating games, such as 20 graphic symbols, continuous JULY 1982

display, and random number generator. The ZX81 can be expanded too. You can increase the memory from 1K to 16K with our Memory Module for $49.95. And you get a comprehensive manual that completely documents the capabilities of the ZX81, and teaches programming from the ground up. In short, you get all the features that have made the Sinclair ZX81 the fastest selling personal computer in the world. And you get the satisfaction and fun of building it yourself. A few years ago, this kind of computer power was simply unavailable to the individual. Even today, most personal computers are too expensive to buy for personal use. But the ZX81 kit can be yours for only $79.95. Take advantage of this unique offer today. To order, send the coupon along with a check or money order. Or for faster delivery, call our toll-free number and use your MasterCard or VISA.

To order call toll free: 800-543 -3000. Ask for operator #509. In Ohio call: 800582 -1364; in Canada call: 513 -729-4300. Ask for operator #509. Phones open 24 hours a day, 7 days a week. Have your

ar

MasterCard or VISA ready. These numbers are for orders only. If you just want information, please write: Sinclair Research Ltd., 2 Sinclair Plaza, Nashua, NH 03061. Fr) C

ODE

07PE

MAIL TO: Sinclair Research Ltd., One Sinclair Plaza, Nashua, NH 03061.

PRICE'

ZX81 Kit

$79.95

16K Memory Module

$49.95

Shipping and Handling

$4.95

'U.S. dollars

QT\'.

AMOUNT

$4.95 TOTAL

Name Address

cih

State

Zip

Sinclair technology is also available in Timex /Sinclair computers under a license from Sinclair Research l.td.

SinIair 7

model prints a 105- character line, and the 12 -cpi expands the line length to 126 characters. Printing output is unidirectional; paper feed is frictional in single sheets or forms. The print impression is operator -selectable at five levels of striking force. $895. CIRCLE NO. 87 ON FREE INFORMATION CARD

simssok._ Additional information on new products covered in this section is available from the manufacturers. Either circle the item's code number on the Free Information Card or write to the manufacturer at the

-NE

Dual- Output Power 2-Supply

address given.

PLAY, RECORD, FAST FORWARD, REWIND, PAUSE /STILL, FRAME ADVANCE, and vari-

able slow motion from 1/4 to '/,o speed. Its tuner /timer section can be set to record four programs over a two -week period, giving the unit an eight -hour recording capability with the longest -playing VHS tapes. The programmable timer offers 105 channels: 12 vhf, 70 uhf, 9 midband, and 14 superband. It can also record CATV with an optional cable adapter. The LCD indicator shows approximate battery time remaining and functions as a tape counter that retains memory for up to several hours when power is cut off. Audio and video jacks are provided for connection with another VCR. $1350. CIRCLE NO. 89 ON FREE INFORMATION CARD

Microprocessor Controlled FM Tuner

The only controls on the front panel of the FM4, the new digital display FM tuner from Quad Electroacoustics, are eight pushbuttons to store and recall stations in memory, a power switch, and a tuning knob. A microprocessor controls all other functions. Once the appropriate preset button is pushed, the microprocessor recalls the required station from memory and automatically adjusts muting and afc. In addition, a bar -graph indicator simultaneously displays signal strength and center tune for the most accurate reception. Specifications include a signal -to-noise ratio of 70 dB (stereo); selectivity, 53 dB; sensitivity (50 -dB quieting), 2.71LiV mono; capture ratio, 2.5 dB; and output at 30% modulation, 100 mV. $625. CIRCLE NO.86 ON FREE INFORMATION CARD

Daisy Wheel Printer

Printer Buffer

A new power supply, the Model 1652, has been announced by B &K- Precision. It features two variable outputs, each with a rated

potential from 0 to 25 V and a current selectable from 0 to 1.5 A. Both outputs can be operated independently of one another or in a tracking mode. In the latter, the B output can be preset to any percentage of the A supply voltage. When the A output is varied, the B output will vary accordingly. The unit is also reported to offer a switching preregulator that reduces internal heat dissipation-permitting operation at full rated output in an environment up to 40°C (104°F). Either supply can be connected with a plus or minus polarity; and either can be floated to an external voltage or connected to a chassis or earth ground. For high voltage or current requirements, the A and B supplies can be connected in series or parallel (with balancing resistors). $465.

A 64K printer buffer said to be compatible with all popular microcomputers and parallel printers has been announced by Quadram

Corporation. Called MicroFazer, the parallel-in/parallel-out data buffer uses standard Centronics signals and can receive data at rates to 4000 cps. The data is then transferred to the printer as rapidly as the printer can handle it. Power can be drawn either from the printer or from a separate 9 -V, 500 mA supply. Standard calculator or battery chargers can also be used. $299. CIRCLE NO. 90 ON FREE INFORMATION CARD

Alpine Car Stereo

CIRCLE NO. 88 ON FREE INFORMATION CARD

Portable VCR

The Model TP -1 from Smith -Corona is a microprocessor -controlled daisy wheel printer that is reported to deliver letter -quality printout at a speed of 144 WPM. It can be used with word processors, personal computers, and small business sytems. There are few controls on the TP -1, and its drop -in ribbon cassettes are said to be easy to load and replace. The printer is available with either a parallel or serial data interface and offers an 88- character ASCII set in 10 and 12 character /inch (cpi) versions. The 10 -cpi 8

The Panasonic Model PV -5500 video cassette recorder's portable section weighs just over eight lb (with battery) and measures approximately 4" X 9" X 10 ". Controls include AUDIO DUB and camera remote ON /OFF. The unit can also be activated by a 16-function wireless remote control that directs POWER ON /OFF, CHANNEL UP /DOWN, TV/VCR selection, TAPE SEARCH, STOP,

The Model 7146 Bi -Level ETR /PLL is Al pine's in -dash car AM /FM stereo /cassette receiver with electronic digital display. It has light-touch ten -station preset, Dolby NR, auto mute, auto seek, a memory function, separate controls for bass and treble, preamp fader, metal tape capability, a local /DX select, engine noise suppressor, automatic cassette reverse, ignition key-off eject, and loudness contour. Specifications are: frequency response with metal tape, 40 to 16,000 Hz ±3 dB; wow and flutter, 0.1% (Wrms); tape S/N with Dolby, 65 dB; and FM sensitivity, 16.3 dBf/I.8 µV (75 ohms). It measures 7 "W X 2 "H X 5 "D. $500. CIRCLE NO. 91 ON FREE INFORMATION CARD

Scanner Converter A converter that is reported to allow complete coverage of the 225 -400-MHz miliPOPULAR ELECTRONICS

Explore the excellence of your ZX81 with a

L7ELrlOPOK 64K memory extension for

$179.95

Give your diminishing memory more byte. MEMOPAK 64K RAM $179.95

MEMOPAK 16K RAM $79.95

Try MEMOPAK with no obligation

The Sinclair ZX81 has revolutionized home computing. The MEMOPAK 64K RAM extends the memory of ZX81 by a further 56K to a full 64K. It is neither switched nor paged and is Directly Addressable. The unit is user transparent and accepts such basic commands as 10 DIM A (9000). It plugs directly into the back of ZX81 and does not inhibit the use of the printer or other add -on units. There is no need for an additional power supply or leads.

With the addition of MEMOPAK 16K, your ZX81 will have a full 16K of Directly Addressable RAM. It is neither switched nor paged and enables you to execute longer and more sophisticated programs and to hold an extended data

You can use our MEMOPAK in your home without obligation. After 10 days if you are not completely satisfied, simply return it for a full refund.

base.

A

Description of memory Sinclair ROM This section of memory switches in or out in 4K blocks to leave space for memory mapping, holds its contents during cassette loads, allows communication between programs, and can be used to run assembly language routines. 16 -32K This area can be used for basic programs and assembly language routines. 32 -64K 32K of RAM memory for basic variables and large arrays. With the MEMOPAK 64K extension the ZX81 is transformed into a powerful computer, suitable-for business, leisure and educational use, at a fraction of the cost of comparable systems.

...

0 -8K 8 -16K

.

.

.

... .

.

.

`wâiii ÄV 1-C U Memory Extention Specialists

Coming soon complete range of ZX81 plug -in peripherals: MEMOTECH Hi -Res Graphics MEMOTECH Digitising Tablets RS232 Interface Centronic Interface and Software Drivers

The 16K and 64K Memopaks come in attractive, custom -designed and engineered cases which fit snugly on to the back of the ZX81 giving a firm connection. Free service on your MEMOPAK Within the first six months, should anything go wrong with your MEMOPAK, return it to us and we will repair or replace it free of charge.

All these products are designed to fit "piggy- back" fashion on to each other and use the ZX81 power supply. Further information forthcoming.

emotech Corp. 7550 W. Yale Ave. Suite 220 Denver, Colo. 80227 would like to try the Memopak. understand that if I'm not complete satisfied, can return it in 10 days for a full refund. Price Qty.

Yes! I

I

Check Visa MC

I

t

Memopak

64k RAM

$

179.95

Memopak

16k RAM

$

79.95

$

4.95

Shipping and Handling

Amount

$

4.95

Total Act. No.

Exp.

t

U.S. Dollars

Name

Street Memotech Corporation 7550 West Yale Ave., Suite 220 Denver,

Colorado

80227

City

State

Zip

PEOL

Ph. (303) 986 -0016 CIRCLE NO. 30 ON FREE INFORMATION CARD

new products tary /federal aircraft band has been announced by Grove Enterprises. Called the

Scanverter, it is used in conjunction with a standard aircraft-band scanner and is said to permit eavesdropping on such interesting communications as Tac -air war games, Coast Guard search and rescue missions, military satellites, and space shuttle radio links to earth. A Grove development called "bandstacking" is claimed to compress the entire uhf aircraft band (175 MHz wide) into the I18- 136 -MHz range tunable on a standard aircraft scanner. Additional tuning and adjustments are said to be unnecessary. Other features include an all -metal cabinet for shielding, an 11 -pole filter for suppression of out -of-band interference, and a frequencyconversion chart printed on the cabinet. The unit is powered by 12 V dc. $100. Address: Grove Enterprises, Brasstown, NC 28902.

Automatic -TapeAdjusting Cassette Deck

The AD -3800 is Aiwa's new top -of- the -line cassette deck featuring its microprocessorcontrolled Digital Automatic Tape Adaptation (D.A.T.A.). This system is reported to automatically check playback output, adjust bias level, and optimize the Dolby B and C noise- reduction (all within 16 seconds) while retaining, if desired, the same setting for up to 24 hours. An Automatic Demagnetizing System (A.D.M.S.) degausses the heads. A dual -capstan tape transport is said to reduce wow and flutter to 0.025 %; and direct- coupled circuitry in the recording amplifier permits signal linearity at levels up to 16 dB. Additional features include a digital electronic display for standard or real -time tape position indication, a memory function, IC logic controls with cue/review operation, switchable MPX filter, auto repeat, timer standby, and a three -color 16 -LED per channel peak level display with hold. S/N is given as 75 dB with Dolby C; frequency range is 20 to 20,000 Hz. $595.

sonal microcomputers. Called the Percom Hard Disk (PHD), the system features a "smart" microprocessor controller and comes in 5M- and 10M -byte versions. The controller can handle up to four drives, providing 40M bytes of on -line storage capacity.

Backup can be from hard disk to hard disk, or from hard to floppy, with an optional floppy-disk controller. Standard configurations are available for the Apple II, Heath Zenith 89, IBM Personal Computer, and the TRS -80 Model III. Direct interfacing is possible to the Model III; host system adapters are provided for the other computers mentioned. The PHD system also includes an RS -232 -C port, for interfacing to any computer with a data terminal I/O channel. Full buffering permits the host computer to accept data as time allows. $2495.

Percom Data Company is now offering 51/4" Winchester disk systems for a variety of per10

Desktop Business Computer

CIRCLE NO. 93 ON FREE INFORMATION CARD

Remote Control for Home Appliances

ECM's Centurian Home Management Sys tern is designed to remotely control home appliances via modules that work from ac outlets. The Centurian also offers modules for the control of thermostats and sprinkler water. The master control panel (which plugs into the ac line) has seven-day programmability, auto- snooze alarm clock, back -lit LCD with dimming -level indicator, and control of up to 274 different combinations of time and day when a given command is to be executed. An optional battery backup takes over in the event of a power failure. The Centurian is said to be compatible with all Sears, Radio Shack, and BSR remote modules. $250.

Casio announces availability of its new FX9000P personal computer. Its keyboard and CRT are built into a single housing that is about the size of an electronic typewriter. The computer features 4K slot -in CMOS RAM packs that can store programs for up to three years for easy retrieval. Expansion is to 32K bytes. The 67 keys comprising the keyboard include a calculator section with a capability to compute built -in standard deviation, linear regression, correlation coefficients, and other mathematical functions commonly used in business and scientific analysis. A graphic display can be used to plot these functions; hard copies may be made with an optional graphics printer. The language of the FX -9000P is CASIO BASIC. $1,200. CIRCLE NO. 95 ON FREE INFORMATION CARD

Bass Enhancer

CIRCLE NO. 94 ON FREE INFORMATION CARD

Wire -Wrap Tester

CIRCLE NO. 92 ON FREE INFORMATION CARD

Winchesters for Micros

disturbing pins adjacent to the ones being tested. The Model 120 -113 is rated for powered connections up to 600 V. It uses its own batteries to test unpowered connections. $23. Address: Desco Industries, Inc., 761 Penarth Ave., Walnut, CA 91789.

The Model 120 -113 continuity and voltage tester from Desco Industries is designed for use with powered or unpowered Wire-Wrap connections. It comes with standard 12gauge sockets on each end. The sockets slip over the pins for positive contact without

Radio Shack is offering a stereo'system accessory that is claimed to improve low -end response of any speaker, while also rejecting

potentially damaging subsonic signals. Called the Bass Enhancer/Subsonic Filter (Model 42- 2106), it uses a slide-control 40160-Hz center frequency adjustment to help match its performance to characteristics of a POPULAR ELECTRONICS

THE QUASAR HHC TAKES COMPUTERS WHERE THEY'VE NEVER BEEN BEFORE. Your Personal, Portable Database. There were places you couldn't take a computer, or use one. Not any more. The Quasar HHC gives you the power of a

computer anywhere you go. Planes, cars and boats, vacations, or wherever you may want to use it. The HHC can be your constant companion. So whatever data files or information you may need or want are always right at hand. The Quasar HHC gives you the full power of a 6502 microprocessor. Programming in Microsoft

Basic or the FORTH -like SNAP. And personal features like file creation, a calculator, and a real time clock/secretary you can program to display reminder messages. File data can be passed from one HHC to another or back and forth between an HHC and another computer. Just connect

both computers through the HHC RS -232C interface, or transmit /receive

over telephone

Quasar

Albany, CA 415- 525 -1113

acoustic coupler.

There's never been a computer like the Quasar HHC. And never a better way to make you more effective. For information on the Quasar HHC Hand -Held Computer, including how to become a dealer or distributor, write on your letterhead to Quasar Group Director HHC.

One Great Idea After Another

SYSTEM HOUSE /OEM

American Medical Instruments

lines with the HHC

Impact Technologies Group, Inc. Salisbury, NC

213 -707 -0776

704 -637-6183

Pentagon Industries, Inc. Chicago, IL

Systems Dunedin,

FL 813 -736 -5154

312 -867-9200

Insta -Data Systems, Inc. Westlake, CA Systems 7, Inc. Houston, TX 713 -468 -4394

DISTRIBUTORS

Internet Corporation San Francisco, CA

RPC Electronics

Pittsburgh,

415 -781 -4507

Straitline Marketing Inc. New York, NY

PA

412 -782 -3770 ,

CIRCLE

NO.

50

ON

FREE

HHC

212 -495 -4225

QUASAR COMPANY, Division of Matsushita Electric Corporation of America 9401 West Grand Avenue, Franklin Park, INFORMATION

CARD

III.

60131. (312) 451 -1200

1We

1

Beat All Prices HEWLETT PACKAPO

b CP]

given speaker system. A boost range of 0 to 12 dB (slide control) compensates for room acoustics and speaker inefficiencies. The subsonic filter rolls off frequencies below 20 Hz to eliminate the effects of low -frequency

I

intermodulation distortion and acoustic feedback. Dimensions of the Bass Enhancer are 13/4" X 7" X 93/4". $50.

or

$

HP/M-125

1979 based.

CP

Your Choice

IMIMMISMMISMI

-

-- _..

CIRCLE NO. 96 ON FREE INFORMATION CARD

-=_..t -----

m

_..

-

NEW HP- 87.... $1889 53/4"

±0.3 °F and a calibration resolution of 0.1 °F. Diameter of the water -resistant tip is 4.19 mm, and the length of the probe cable is 4'. Output is 1 mV/°F. Minimum DMM load impedance is 1 megohm: time constant for the readout, 1.2 s. Approximate life of the 9V battery (included) is given as 300 hours. $24.95. Address: Alpha Magnum Corp., 7555 Jurupa Ave., #D, Riverside, CA

SWR Meter

CALL

DUAL MASTER DISK DRIVE

HP -7470 PLOTTER 5 5

eK' products

$1245 $3599 $4399

MEG. WINCHESTER HARD DISK MEG. WIN. WI53/4" DD SD FLOPPY .

APPLE II PLUS, 48K APPLE III

CALL CALL

TI 9914

$364 $255 5989 $2489 $3095

COMMODORE VIC-20 NEC PC-8001A, 32K XEROX 820 5'4" DISK DRIVES XEROX 820 8" DISK DRIVES

92054.

Speaker /Amp for Portable Stereos

TI CALCULATORS TI -55

$36 $36 $79 $169

I I

TIP -BUSINESS ANALYSIS II TIP -58C TIP -59 TIP- P -100C

HP -41CV w /Five

1

times

List. $325

$237 NOW IN STOCK

i1

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more memory

Built In

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$149

t.! l'j LJ 6. U

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$189

CIRCLE NO. 97 ON FREE INFORMATION CARD

HP -41C

list. $250

t-,

I

The new M-827 from Palomar Engineers is designed to compute standing wave ratios automatically and display them on a light bar. SWR reading is claimed to be accurate regardless of input power level (which is also displayed on a light bar adjacent to the SWR display). The M -827 has a frequency range rated at 1 to 30 MHz and power range of 20, 200, and 2000 W. The SWR scale is 1 to 10, with logarithmic response. $98.

HP -41CV PRINTER

FM Stereo Signal Booster

$289 $99 $168 $99

HP -41CV OPTICAL WAND HP -41CV CARD READER HP- 821060A HP -IL MODULE HP- $2161A DIGITAL CASSETTE DRIVE, $419 HP- 82162A IL PRINTER $375 HP- 41CICV EXT. FUNC. MEM. MOD.. $62.75 HP-41C/CV EXTENDED MEM.MOD.. $62.75 HP-11C $107.95 HP -12C $119.95 HP-33C $74.95 HP-34C $117.95

ATARI®800 Ó

noo

...3n0.0

$689 s Al L,,,,,

°°

ATARI W

pRICE

NEW LO

ATARI 400 ATARI ATARI ATARI ATARI

830 825 410 810

$339

ACOUSTIC MODEM 80 COL. IMPACT PRINT

$145 $565 $79 $419

PROG. RECORDER

DISK DRIVE

(3151478-6800

ary o m pu ter .,,hegtprices ro chn,o

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The Finney Company has a new addition to its automobile FM Booster line, called the Stereo III. The device is intended for use with any auto AM /FM radio. When the Stereo III is in operation, a gain of 16 times the normal FM signal strength is said to be possible. This is especially useful in fringe areas; but even in strong signal areas, according to Finney, the receiving circuits will not overload. The unit has dual gain -control pushbuttons for local and fringe reception, an antenna trimmer, and dual LED oN indicators. The Stereo III is a one -piece unit designed to mount under the dash. $40. CIRCLE NO. 98 ON FREE INFORMATION CARD

ystQm,z

"utno,.

P.O. Box 1073

Syracuse,N.Y.13201,

CIRCLE NO. 99 ON FREE INFORMATION CARD

Dual -Trace Scope Hitachi's V -209 is a portable 20 -MHz dual trace oscilloscope with a 31/2" CRT. It has an internal rechargeable battery, a built -in circuit for TV sync separation, auto focus, and front -panel controls grouped into functionally related clusters. Vertical sensitivity is rated at 5 mV /div. to 5 V /div. in 10 calibrated steps, 1 -2 -5 sequence. A 5X magnification extends the maximum deflection rate to mV /div. Calibrated sweep speeds extend from 0.5 µs /div. to 0.2 us/div. in 18 1

DMM

Temperature Probe

All

609 Butternut St.

Puce, donot ,!,..nipp11,,,

STEREO

The new "Steppin' Out 3" Mura is designed to give the owners of personal-size stereo radios and tape players (all brands) the capability of playing them out loud. Designated Model HS -45, it has four speakers consisting of two 5" high -compliance woofers and two 1 1 " aluminized -dome tweeters. Specifications are: 4 W continuous power output at 1 kHz; a frequency range of 80 to 24,000 Hz; 40 dB channel separation. Features include a LED "on" indicator bass /treble switch and dipole telescoping antenna. Measuring 18" X 8" X 3 ", and powered by eight "D" batteries, the unit comes wth a 12 -V dc adapter input jack, a one -foot audio connecting cable,.and adjustable carrying strap with shoulder pad. $80.

The Alpha Magnum Corp. Model TTF temperature probe is designed to work in conjunction with a digital multimeter. With a sensitivity range from -67 °F to +302 °F, the TTF is claimed to offer an accuracy of

steps,

1

-2 -5 sequence. Display modes are

CHI, CH2 (Normal or Invert), Alternate, Chopped (250 -kHz rate), and Added. The V -209 measures 8.5"W X 4.3" H X 13.8"D and weighs 10 lb. Two probes are included. $995. CIRCLE NO. 100 ON FREE INFORMATION CARD

CIRCLE NO. 39 ON FREE INFORMATION CARD

POPULAR ELECTRONICS

7 +11 SWD PARTS KITS

Switch to Bambi!

MITSUMI VARACTOR

UHF TUNER

Fj

Ii Ii

$34.95 Fleg. Range

UHF47O -

Electronically

li

Model UES -Á56F

li

p OIm u

889MHz

Antenna Input 75 ohms

Ill

1.

Channels 14-83 Output Charnel 3

PARI

KIT

No

DESCRIPTION

NO

PRICE

vn -sw

Ventre

2

CBI -SW

Printed Circuit Board, Pre -Drilled

3

WI -SW

P.C.B. Potentiometers.

1

5

4

F1135-SW

5

PT1

fi

PP2 -SW

7

SS14 -SW

-SW

... ....

UHF Tuner, Model UES -A58F

1

-20K,

-IK,

1

834.95 18.95

and

-10K ohms, 7- pieces

95

5

Resistor Kit, '4 Wan, 5% Carbon Film, 32- pieces...

4.96

Power Transformer. PRI- IIIVAC, SEC -24VAC,

directing the inputs to any or all of the three outputs.

250ma

8 95

Panel Mount Potentiometers and Knobs,

1

-1KBT

-5KAT w/Switch

and

1

IC's

7

Bambi Electronic Video Switch ... makes switching of your VCR/VTR, Pay Tv Decoders, Cable TV, Video Discs, Video Games, Closed Circuit TV, Antennae and Microcomputer as easy as pushing buttons.

95

5

Now you. can eliminate ... the drudgery of disconnec-ing and reconnecting your video equipment each time you use it -. the tangled mess of cables which are impossible to 'race out ...not being able to use more than one function .

-pcs, Diodes 4 -pcs, Regulators

Heat Sink

-SW

1

2

-pcs

29.95

-piece

Electrolytic Capacitor Kit, 9- pieces

5 95

8

CE9

9

CC33 -SW

Ceramic Disk Capacitor Kit, 50 W.V., 33- pieces.... 7.95

CT -SW

Varible Ceramic Trimmer Capacitor Kit,

10

5 11

14-SW

-85pfd, 8- pieces

Coil Kit" 18mhs 2- pieces. .22p.hs

inductors) and Core ICS -SW

12

5 95 1

-piece (prewound

737 -12 Ferrite Torraid

1

with 3 h. of

#26

5.00

wire

-pin 5- pieces

I.C. Sockets, Tin inlay, 8

1.95

and 14 -pin 2- pieces SR -SW

13

Speaker,

4x6"

Oval and Prepunched

14.95

Wood Enclosure MISC -SW

14

at

a

time_

Bambi lets you enjoy using your video equipment the way it st-ould be ... electronically and on line at the push of a button.

Model BEVS-1

Misc. Pane Kit Includes Hardware, 16/32, 8/32 Nuts, 6 Bolts), Hookup Wire, Ant. Terms, DPDT Ant. Switch, Fuse, Fuseholder,

When Ordering All Items,

(1

etc..

th -u 14). Total

9.95 139.95

Price

BAMBI

Q^ O Q O.O

O O

UHF ANTENNAS and ACCESSORIES

MDS- AMATEUR -ETV 32 ELEMENT

VAGI ANTENNA

lool000toottozotozo5 38w' NOTA KIT 1.9 -2.5 GHz LENGTH 23 dB AVERAGE GAIN DIE CAST WATERPROOF HOUSING WITH 4Ys" x 2%2" AREA FOR ELECTRONICS COMMERCIAL GRADE INCLUDES MOUNTING HARDWARE

MAE -1

$19.95

32 Element YAGI Antenna

V

J1 `,,W r

7Y7,7,\ VHF -UHF WIDEBAND

ANTENNA AMPLIFIER

Axnex

fMPllnf

-

Check the quality of Bambi against that of much higher priced competition. All solid state electronic switching provides low attenuation (3dB), wide frequency response (40890 MHz), and excellent isolation between signal sources leach I/O section individually sheilded for 85dB min. isolation).

The SWD -1 Video Convener is utilized on cable TV systems to re-

move the KHz's signal from a distorted video (channel 3 in/ out) and also pass thru the normal undistorted /detected audio signal. Rocker switch selects operating mode to remove KHz's distortion from the video or pass all other channels normally. Simple to assemble -less than 30 minutes. Pre -tuned. Input/output Channel 3. Impedance 75 ohms. 117VAC.

900 MHz

$69.95

12 dB GAIN

o 5dB

A Revolutionary New One Stage HYBRID IC Broadband Amplifier This unit is not available anywhere else in the worm. One unit serves ru,niy .>> end is available in Kit or Assembled form. Ideal for outdoor or indoor use SP ,aanee is 75 ohms. Amplifier includes separate feedpow supply. Ens mbled in 25 minutes. No toils, capacitors etc. to tune or adjust.

ALL -1 Complete Kit with power supply ALL -1 Wired and Tested with power supply

VTR ACCESSORIES SIMPLE SIMON VIDEO STABILIZER

11

Simple Simon Video Stabilizer. Model VS -125, eliminates the vertical roll and jitter from "copy guard video tapes when playing through large screen projectors or on another VTR. Simple to use, just adjust

/

P24. 95

the lock control for a stable picture. Once the control is set, the tape will play all the way through without further adjustments. Includes 12V power supply.

$34 95

VS-125 Video Stabilizer, wired

He

Na

routing system. Simple Simons VSB300 Video Switching Box enables a variety of video components together for easy viewing /dubbing. Also you gain the ability to record one channel while viewing another. Unit includes two F -type quick connector ended cables.

.,.

V'

STVA -3

Yagi Antenna,

516.95

14.518, 75 ohm, Chan, 60-68

'a

PART NO

SIMPLE SIMON ELECTRONIC KITS, Yagi Antenna, 11.5 dB, 75 ohm, Chan. 42

RG -59/U

75 ohm Low Loss Coax Cable

F-59

Coaxial Connectors, ea

MT -1

Special

UHF 75 -3W ohm Matching Transformer,

-54

59.95

S

.12

p

/ft 39

2CB1 -PWD

Printed Circuit Board, Pre- drilled

3

3TP11 -PWD

PCB Potentiometers 1

ea..

145

-1K, and

1

-50k.

4-20K,

Ili

I

534.95 18.95

-.SK, 2 -10K,

2

-5K,

..

peces)

4

4FR -31 -PWD

Resistor Kit, '4W, 5% 29 -pcs, y W 2-pcs

5

5PT1 -PWD

Power Transformer, PRI- 117VAC, SEC -24VAC at

6

6PP2 -PWD

7

7SS17 -PWD

9 95

Panel Mount Potentiometers and Knobs,

IC's

1

-1KBT

-5KAT with switch

1

7 -pcs,

8.95 4 95

500ma

and

5 95

Diodes 4-pcs, Regulators 2 -pcs

Transistors 2 -pcs,

Hat

29.95

Sinks 2 -pos

8

8CE14-PWD

Electrolytic Capacitor Kit, 14 -peces

8 95

9

9CC20-PWD

Ceramic Disk Capacitor Kit, 50 WV, 20 -pcs

7 95

10

10CT5 -PWD

Varible Ceramic Trimmer Capacite,

5- 65pfd, 5- pieces 11L5 -PWD

with 6 ft. 12

121CS -PWD

13

13SR -PWD

IC

2

495

.

'Brits 3-pc.,

Coil Kit,

inductors) and

T37

.22yuhs

1

-piece (prewound

12 Ferrite Toreid cores

#26 we

Sockets, Tin inlay, 8 pin 4-pss, 14 pin

6 00 1

-pc

and 16 pin 2 -pcs

14

14MISC -PWD

2 95

Enclosure with PM Speaker and Pre -drilled Backpanel for mounting PCB and Ant. Terms

14.95

Misc. Parts Kit Includes Hardware, (6/32, 8/32 Nuts B Botts), Hookup Wire, Solder, Am. Terms DPDT Am. Switch, Fuse, Fuseholder, etc

15

15MC16-PWD

Mica Capacitors 2- pinces

TM

Inc.

All Other Ordere.

3871 S, Valley View, Suite 12 Dept. P Las Vegas, Nevada 89103 Tel: (702) 322 -5273

11850 S. Hawthorne Blvd. P

Hawthorne, Calif. 90250 Tel: (213) 675 -3347

9.95

Mylar Capacitors, 14-pcs and Silver

When Ordering All Items,

Calif. Orders:

Dept.

PRICE

2

14.518, 75 ohm, Chan. 44-52... 516.95

SIVA -1

DESCRIPTION

Varactor UHF Tuner, Model UES -Á56f

you to bring

$19.95

PWD

1Vr1 -PWD

9laepN

VSB -300 Video Switching Box, wired

STVA -4 Yogi Antenna,

Input Return Loss Isolation Power Req. Dimensions Weight

1

Excellent in isolation and no loss

sIMPt:E

Noise

PARTS KITS

SIMPLE SIMON VIDEO SWITCHING BOX Control Center

75 oho, 3d8 tide 4d8 i1 d8 12d8 min 65dß min 117VAC 60 Hz, 2W 10y. W s 634 D x 3XH 4v, lbs

Signal Loss

7 +11

$54.95

The Affordable Video

Input/Diuput Impedance

INTRODUCING OUR

11

Our New STVA 14.5 dB GAIN, 14 ELEMENT CORNER REFLECTOR YAGI ANTENNA

Bambï s Specaications:

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SWD -1 VIDEO CONVERTER FOR CABLE TV

SWD-1 Video Converter Kit

MODEL ALLA

50 MHz

Barnbïs bons panel was designed with the user in mind. Computer styled construction. with soh-touch keyboard (rated for over 10 million operations), arranged in matrix form allows easy input/output selection without refering to charts. Functions selected through the keyboard are immediately displayed on the 18 LED status indicators.

(1

-15), Total Price

7

95

159,95

Available by Mail Order Only Send Check' or Money Order. Minimum Order: $16.95. Add 10% Shipping and Handling on orders under $40.00. For orders over $40.00, add 5%. Minimum Shipping and Handling $2.00. Cat. $1.00 VISA and Mastercard Acceptable

-

-

-Check orders will be field 30 days before shipping.

CNTEJ1INMCNT

eimizalICS

By Len Feldman

The AM Stereo Situation AM STEREO, its proponents main tain, is an idea whose time is overdue. The increasing importance of the listening audience in automobiles has been the driving force behind broadcasters' efforts to bring to the AM band what FM listeners have enjoyed for years- stereo sound. Most car audio systems include a tuner able to receive FM stereo; but in a moving vehicle this is not always as satisfying as it might be. FM transmission frequencies and low -gain, non-directional mobile antennas limit the range of satisfactory reception to between 20 and 50 miles, while signal reflections, causing distortion, are generally far more severe in a moving vehicle than in a living room. AM stations, by contrast, can be heard at great distances from the transmitter, and groundwave reception is not subject to the audible effects of multipath. (Skywave reception at night is another story.) No wonder, then, that by the mid- 1970s, AM broadcasters were crying for stereo capability. After five years of deliberation, a "false start" almost two years ago, and recent rumors that a single system for stereo AM transmission would be selected, the FCC surprised everyone by handing down what it calls a "marketplace" decision. In fact, this is no decision at all, because it allows any AM broadcast station to transmit stereo programming using any one of five systems that have been under study for many years. To many, this non -decision is tantamount to sounding a death knell for stereo AM. Others say that, ultimately, a single system will be favored by the consumer. It would be nice if a stereo AM receiver could be constructed to automatically detect which of the five broadcast sys-

-

block diagrams of possible receiving circuits should reveal that there is no single circuit approach that will decode for all of them.

Frequency and Amplitude Modulation. The Belar system frequency -modulates the r -f carrier with a pre- emphaR) signal. The maxisized, 400 -1,,s, (L mum frequency deviation of the carrier varies from 312.5 Hz at low frequencies to 6250 Hz at higher audio frequencies. The (L + R) signal amplitude -modulates the frequency -modulated r -f carrier. The Belar system is therefore called an AM -FM system. It also includes a pilot tone of 10 Hz (for automatic identifi-

-

v pFBI-F 11 -AM /FM

-

signal. An equivalent way of describing the Harris system is to consider it as two carL+R

STAGES

LEF

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AUDIO MAT RlR

SIGNAL

LIMITER REMOVES

L-R

HDISCRIMINATORI-A.,

DE

RIGHT

EMPHASIS

AuDlo

AM

Fig.

1.

Belar's system requires separate AM and FM detector circuits.

LOPASS

HMIXER/

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FRONT

+ 90° PHASE SHIFTER

F

OUTPUT

END

t VC0

MIXER/ DEMOD

L+R

AUDIO MATRIX L

FILTER

DEMOD

LOOP

FILTER

+R 8

L

-R

GAIN ED

-Vigo AUDIO

-RIGHT AUDIO

STEREO

LIGHT

t

20 -25 -H1

STEREO

MONO

TONE DETECTOR

LOW-PASS FILTER

AUTOMATIC SWITCHING

REDUCED L

-R

L-R L

PHASE LOCKED LOOP

Fig. 2. Basic configuration of an early version of the Harris system.

L+R

FRONT END

DETECTOR

1

tems it was receiving and then switch in

appropriate decoder circuitry. Indeed, such a receiver may be possible some day, but this is almost certain to make its cost prohibitive. That's because the five systems which have been "approved" for trial by the FCC are mutually incompatible, in spite of some superficial similar-

14

Variable Phase and Gain. The Harris system modulates two carriers that are separated in phase by up to 90 degrees. They are referred to as the in -phase carrier and the quadrature carrier. The full (L + R) signal modulates the in -phase R) signal carrier while a reduced (L modulates the quadrature carrier. The two modulated carriers are then combined into one signal whose phase and amplitude are used to modulate the phase and amplitude of the transmitted

ENVELOPE DETECTOR

v

ities. Here is a brief description of each of the systems, gleaned from the FCC's Report and Order. A look at the associated

cation or switching from mono to stereo at the receiver). A possible decoder circuit for the Belar system (Fig. 1) has r-f and i -f stages identical to those in a normal AM receiver. Output of the i -f amplifier is divided into two separate detection signal paths. One signal is applied to a conventional envelope detector, where the (L + R) signal is recovered. The other path applies the signal, after appropriate limiting, to an FM detector such as a discriminator. After detection and deR) signal emphasis, the recovered (L matrixed with the (L + R) to yield separate left and right outputs.

SUMMING AMP

PL L

AMPL TUDE MODULATOR

..01 AMPLIFIER

+5°

PHASE SHIFTER

STEREO LIGHT

L +R AUDIO

L

90°

PHASE SHIFTER

L

PRODUCT DEMODULATOR

QUADRATURE DEMODULATOR

BANDPASS NETWORK

AUDIO

AUDIO MATRIX NETWORK

t

LOW -FREO

L EFT

STEREO TONE DETECTOR

I

RA

GT

UDHI O

L-RF

L-R STEREO/ MONO SWITCH

-45°

PHASE

SHIFTER

Fig. 3. Single- receiver diagram for Kahn /Hazeltine ISB system. POPULAR ELECTRONICS

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14 -16 EXTRACTOR 24 -40 CMOS SAFE EXTRACTOR

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JULY 1982

15

audio of 15 Hz which angle-modulates the carrier by approximately 0.1 radian. Interestingly, two ordinary AM radios, placed at the left and right of the listener, can actually be used to recover a stereo effect when the Kahn /Hazeltine system is broadcast. The left -hand radio is tuned slightly below center frequency of the ISB transmission, while the other radio is tuned slightly above center frequency. Thus adjusted, the two radios will directly demodulate the upper and lower side bands and will produce left and right audio signals. Kahn has also developed a decoder that will work from the i -f of a single AM receiver (Fig. 3).

riers that are separated by a phase angle that can vary from 90 to 30 degrees. The left channel modulates one of these carriers while the right channel modulates the other. The variable angle between the carriers is directly related to the gain -reR) channel. duction factor of the (L In order to properly decode the Harris signal, the instantaneous gain used in the (L - R) channel must be transmitted along with the signal. This is done by varying the frequency of an accompanying pilot tone from 55 to 96 Hz, dependR) ing on gain reduction of the (L channel. Harris calls it the V -CPM, for Variable Compatible Phase Multiplex. An early version of a receiving circuit for the Harris system is shown in Fig. 2. A phase -locked loop circuit regenerates unmodulated i -f from the incoming i-f signal. This regenerated i -f is 90 degrees out of phase with the incoming modulated i -f, so the mixer demodulates the quadrature (L - R) signal. A 90- degree phase shift produces unmodulated i-f that is in phase with the incoming modulated i -f. This signal, combined with the modulated i -f signal in another mixer, is used to demodulate the (L + R) signal. The two signals are adjusted for equal gain and are then matrixed to yield left and right audio signals.

-

-

Phase and Amplitude Modulation. R) The Magnavox system uses the (L signal to phase -modulate the r-f carrier and the (L + R) signal to amplitude modulate the phase -modulated carrier. This type of system is known as an AMPM system. Magnavox also phase -modulates the r -f carrier with a 5 -Hz pilot tone of 4 radians peak deviation. A receiver suitable for decoding the Magnavox signal has its i -f amplifier output split in two directions (Fig. 4). An envelope detector is used to extract the AM information and to detect the r-f carrier level for automatic gain control. At the same time, i -f output is limited and applied to a PM detector which recovers R) signal and the 5 -Hz pilot the (L

-

Independent Sidebands. The Kahn/ Hazeltine system phase -modulates the rR) signal such f carrier with the (L that amplitude modulation of the carrier places most of the left-channel stereo information in the lower sideband and

The

-

rive the left and right stereo signals.

Phase Shift and Forced Compatibility. The Motorola system amplitude modulates two r-f carriers that are separated by 90 degrees. The (L + R) signal

most of the right -channel stereo information in the upper sideband. The system is called an "independent sideband" (ISB) system. Kahn /Hazeltine uses a pilot tone CONVENTIONAL AM FRONT END

-

R) and recovered (L tone. (L + R) signals are then matrixed to de-

L

HCONVENTIONAL AM

+R AUDIO

LEFT AUDIO

ENVELOPE DETECTOR AUDIO

MATRIX AMPLITUDE LIMITER W PHASE DETECTOR

lL -R

AUDIO

STEREO/ MONO SW

COL

Ir

H

RIGHT AUDIO

SIGNTNRAOL

S -Ha DETECTOR

STEREO

ID LIGHT

Fig. 4. Basic receiver configuration for Magnavox system.

IF INPUT

i

-

Which System is Best? Each proponent cites advantages for his system and disadvantages for those of his opponents. If there is, in fact, a "best" system, what likelihood is there that the listening public will really contribute to a decision based on technical merit? FCC Commissioner Abbot Washburn held out little hope for intelligent decision making in his dissenting statement attached to the official FCC Report and Order on AM stereo. His statement said, in part, " .. whichever system or systems evolve will be based not on true consumer preference resulting from comparisons of the five systems, but rather on the size of promotion and merchandising expenditures and like factors." Commissioner Washburn summed up the feeling of many industry experts by stating, "... this type of marketplace referendum is not the way to make an informed choice, if indeed it results in a choice at all ..." LEFT

-AUDIO

AUDIO

SYNCHRONOUS

L -R

cos e

DETECTOR

1 LIMITER

O DIVIDE BY FOUR COUNTER

-

L+R

GATED ENVELOPE DETECTOR

o

-

R) modulates one carrier while the (L signal modulates the other. The two carriers are then added together. At this point, the system is linear; however, the amplitude of the resultant signal is not fully compatible with monophonic envelope- detector type AM receivers. To achieve better compatibility, the combined signal is first hard -limited and then remodulated with the (L + R) signal. This destroys the linearity which the system had previously, but establishes mono compatibility for the system-an absolute requirement for any system being considered. Motorola calls its system CQUAM, for Compatible Quadrature Amplitude Modulation. Also included is a 25 -Hz pilot tone. A C-QUAM receiver obtains (L + R) information from a gated envelope detector. Two synchronous detectors are used to demodulate the phase -modulated information quadrature component and the cosine of the phase angle. These outputs are fed to an analog divider, which R). The yields the difference signal (L envelope detector output, (L + R), and R), are applied the divider output, (L to an audio matrix that provides the desired stereo signals. A fourth demodulator controls the operation of the phase locked loop and the squelch circuitry.

90°

1

SYNCHRONOUS DETECTOR

e-

SYNCHRONOUS

DETECTOR

ANALOG DIVIDER

cosh

MATRIX WITH STEREO/MONO SWITCHING

L-R

PILOT -TONE DETECTOR

STEREO LIGHT

ID

(25Hz)

PHASE LOCKED LOOP AND SQUELCH

CONTROL

RIGHT

~AUDIO

-

4

VOLTAGE CONTROLLED OSCILLATOR X

IF

FREQUENCY

Fig. 5. Block diagram of stereo AM decoder for Motorola C-QUAM system. 18

POPULAR ELECTRONICS

Audio

c Month

CHOSEN BY T

EDITORS OF POPULAR ELECTRONICS

ivrfirirry

Shure V15 Type VPhono Cartridge THE new V15 Type V phono car tridge succeeds the Type IV as Shure's top -of-the -line cartridge. It features a thin -wall beryllium stylus cantilever that reduces its effective tip mass to half that of the Type IV. This contributes to giving the Type V substantially improved "trackability" at the higher audio frequencies. ( "Trackabilitÿ" is a term coined by Shure to describe the ability of a stylus to follow groove modulation at any frequency or velocity in the audio range, without losing contact with the groove or damaging the record's soft vinyl material.) The V15 Type V is supplied with a novel mounting and alignment fixture that greatly simplifies its installation. Purchasers of the cartridge are entitled to receive at no charge, a copy of a new test record (the TTR -117, discussed in "Entertainment Electronics" in the June 1982 POPULAR ELECTRONICS) which can be used to establish a single -valued "Total Trackability Index" (TTI) for any cartridge, in addition to checking other aspects of a cartridge's performance. The price of the Shure V15 Type V is $250. The TTR -117 record is available for $15 (free with cartridge).

The V15 Type V is shown above and in tonearm with leveling stylus installed. JULY 1982

General Description. The Type V makes it possible to track any amount of groove modulation that we know to exist on commercial music records, at a playing force of 1 gram. It can track 60 cm /s at 10 kHz, and up to 80 cm/s in the 4-to5 -kHz range. This is made possible principally by Shure's new Microwall/BeTM stylus cantilever. Shure developed a process for forming a thin sheet of beryllium (0.5 mils thick) into a tube with a diameter of 18 mils. The result is an effective tip mass (exclusive of the diamond tip itself) considerably less than half that of the Type IV stylus shank-increasing its resonance frequency about 50 %, to 33 kHz. Because the Microwall /Be shank is stiffer and lighter, it can be made longer than previous shanks without sacrificing performance. This lowers the vertical tracking angle to 20 degrees (the international standard) when the cartridge is operated at its nominal 1 -gram force. Unlike most cartridges, however, the V15

Type V is not rated for operation over a range of forces, but is simply specified for 1 gram. The diamond tip itself has the hyperelliptical shape (0.2 X 1.5 mils) developed by Shure some years ago and used in many of their better cartridges. It is a modified line- contact shape that gives low tracking distortion and record wear. The contact surfaces of the diamond are MASARTM polished to an exceptional smoothness, for reduced noise and record wear. The fixed coils and magnetic structure of the V15 Type V have a lower impedance than previous models, which makes its frequency response less dependent on the load capacitance and resistance. Output level, however, has not been sacrificed, due to the high efficiency of Shure's laminated pole -piece design. The contact pins are gold -plated and the entire body is encapsulated for long, trouble -free life. Other features of previous Shure cartridges have also been retained. The Dynamic Stabilizer, first used on the Type IV, continues to damp the arm/cartridge resonance. The brush, containing more than 10,000 electrically- conductive fibers, removes dust from the record grooves ahead of the stylus and simultaneously discharges accumulations of static electricity that can cause noise and attract dust. The stabilizer requires an additional 0.5 gram of downward force to overcome its weight, so the arm must be set for 1.5 grams to obtain the rated tracking force of 1 gram on the stylus. Swung all the way down, the stabilizer serves as a stylus guard, and it locks in an upward position when not in use. In addition, a different type of guard protects the Type V stylus. Called the Side -Guard system, it is a square- crosssection channel surrounding the stylus shank. When the cartridge is subjected to a side thrust, such as scraping the pickup across a record, the entire stylus system is pushed upward into the cartridge body, guided by the angled walls of the Side -Guard tube. This feature has no effect on the normal operation of the stylus, and even offers protection against violent scrubbing motion that would destroy an unprotected stylus. 17

VIDEO

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Enhancer/Stabilizer Improve picture detail, sharpness. Defeat copyguard. Reduce noise.

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Full featured ENHANCER /STABILIZER, MFJ -1421. Enhance Control dramatically improves picture clarity, detail, sharpness, contrast. See individual strands of hair, blades of grass. Noise Cancel Control reduces snow, picture noise. Gain Control improves faded picture. Enhance before recording to cancel VTR and tape loss. Makes copies as good as the original. Enhance during viewing to bring out detail, sharpness. Makes viewing quality of 6 hour mode recordings comparable to 2 hour mode. Stabilize Control removes copyguard. Stops picture roll and jitter. Play copyguarded tapes on any TV set (requires RF modulator). Duplicate any prerecorded tapes. Use as distribution amplifier. 3 outputs. For video only. 7x2x6 inches. Order from MFJ and try it. If not delighted, return it within 30 days for refund (less shipping). One year unconditional guarantee. Order today. Call TOLL FREE 800.647-1800. Charge VISA,MC. Or mail check, money order. Write for free catalog. C

...

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USA.

ENTERPRISES,

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ANTENNA Rivals long wires

$79,94..00 5 shipping)

MFJ -1020 NEW INDOOR ACTIVE ANTENNA sits on your desk ready to listen to the world. Rivals, can often exceed, reception of outside long wire. Unique Tuned Active Antenna minimizes intermod, provides RF selectivity, reduces noise outside tuned band. Also use as preselector for external antenna. Covers 300 KHz to 30 MHz in 5 bands. Adjustable telescoping antenna. Controls: Tune, Band Selector, Gain, On -Off/Bypass. LED. FET, bipolar circuitry. Phono jack for external ant. 6x2x6 in. 9-12 VDC or 9 V battery for portable use. 110 VAC with optional AC adapter, MFJ -1312, $9.95. Order from MFJ and try It. If not delighted, return it within 30 days for refund (less shipping). One year unconditional guarantee. Order today. Call TOLL FREE 800-647-1800. Charge VISA, MC. Or mail check, money order.

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dB from 40 to 15,000 or 20,000 Hz, depending on the channel. Channel separation was about 26 dB up to 10,000 Hz, and 14 dB at 20,000 Hz. The smooth, wide response of the cartridge was further demonstrated by its response to the 1000-Hz square wave on the CBS STR112 test record. The playback waveform had almost no overshoot and a very slight ringing on its flat portions (mostly from the record, which rings at about 40,000 Hz). The tracking distortion was measured in the midrange with the Shure TTR-102 test record, and at high frequencies with the TTR -103 record. The TTR -102 has IM distortion test bands with 400 and 4000 Hz signals, at levels from 6.9 to 27.1 cm /s. The output of the cartridge was measured on a standard IM analyzer. The distortion varied randomly between 1 and 1.7% over the full range of levels. These are roughly the residual levels on the record, and they confirm the excellent linearity and trackability of the cartridge at low and middle frequencies. The TTR -103 record has shaped 10.8 kHz tone bursts at a 270 -Hz rate over a range of velocities. The effectiveness of the Microwall/Be shank in improving high- frequency trackability was shown by the negligible distortion reading from the cartridge output-0.7% from 15 to 30 cm probably the residual distor-

/s-

tion of the setup. User Comment. It is difficult to find anything significant in the performance of the V15 Type V to criticize. With a response flatness rivalling that

Replacement styli for the V15 Type V are the V15V-VN5HE, nude hyperelliptical tip; the V15V- G -VN5G, nude spherical tip; and the VN578E biradial tip optional 78 -rpm stylus.

Laboratory Measurements. The

Covers 300 KHz - 30 MHz. For SWL, BCL, VLF DXers. i

CALL TOLL FREE

The final feature of the Type V is not a part of the cartridge at all. Yet in many respects it is the most important consideration from the standpoint of the typical user. Since one of the most critical tasks in setting up a music system involves the correct mounting of the phono cartridge in the headshell, it is vital that the user be able to do this job properly. If the stylus is not removed during this process, there is a real danger of damaging it. Even if you do remove the stylus, you risk dropping parts used in the mounting assembly. Shure has simplified this process by providing plastic captive nuts that slide into slots on the cartridge body and are retained there while one inserts the screws from the other side of the headshell. The major innovation, however, is the provision of a precisely machined mounting jig that holds the cartridge body in place (with the stylus removed) while the headshell is being fastened to it. With the cartridge correctly installed and oriented, a plastic leveling stylus is inserted into the cartridge body. This is use to rotate the entire headshell (if necessary), ensuring that the playing stylus will be perpendicular to the record surface. When the leveling stylus is removed and the playing stylus inserted, the V15 Type V is fully mounted. This procedure is much easier (and faster) to do than to describe. It should require no more than a minute or two. It also seems to be at least as accurate as any other alignment system we have

USA.

ENTERPRISES, INCORPORATED

Louisville Road, Starkville, MS 39759

CIRCLE NO. 32 ON FREE INFORMATION CARD

Shure V15 Type V was installed in a moderately massive tonearm (about 18 grams). It was operated at its rated 1gram force, except when we determined its minimum tracking requirements (for which it had to be operated at 0.75 grams or less). At 1 gram, it played every part of the Shure "Audio Obstacle Course" records (ERA III and ERA IV), plus all our other high -level test records. In the test tonearm, the cartridge resonated at 8 to 9 Hz, not far from the ideal 10 -Hz range. The Dynamic Stabilizer damped the resonance so effectively that we had to disable it to get a positive indication of any arm resonance. The cartridge output at 3.54 cm /s was 3.4 MV, with the channel levels balanced within 0.4 dB. The vertical stylus angle was the rated 20 degrees. We measured the frequency response of the cartridge with the CBS STR 100 test record, loading the cartridge with its rated 47,000 ohms and a number of capacitance values from 70 to 440 pF. The flattest response was obtained with 280 pF, close to the rated 250 pF, and we used this value for all other tests. The frequency response was flat within +0, -1

Response to square -wave test.

of some amplifiers, sufficient trackability to cope with any signal it will encounter on today's disc recordings, better channel separation than most records and many FM tuners, and distortions so low that they cannot readily be distinguished from the residual levels on available test records, the Type V would seem to be a virtually ideal cartridge. The playback sound from the V15 Type V had no characteristic coloration or quality that we could detect. What one hears is what is on the record -for better or for worse. The owner of a V15 Type V can not only be assured that he has purchased one of the finest cartridges that money can buy, but that he has installed it in the optimum manner to deliver its full performance. That is no small achievement, Julian Hirsch in our view.

-

CIRCLE NO. 101 ON FREE INFORMATION CARD

POPULARELECTRONICS

HE GRAPHIC

DIFFERENC

BETWEEN ATARI COMPUTERS AND ALL OTHERS.

STATES AND CAPITALS e

-1:f15:.14

: ,,,.

'4.(%)4/4

3.7 million reasons why the ATARI Home Computer is something to see. The display screen used with our computers is composed of 192 horizontal lines, each containing 320 dots. Delivering color and luminosity instructions to each dot for a second requires 3.7 million cycles...a lot of work for the normal 6502 processor. That's why the ATARI computer has equipped its 6502 with its own electronic assistant. It's called ANTIC, and it handles all the display work, leaving the 6502 free to handle the rest. What this means to you is uncompromisingly spectacular display capabilities without loss of computer power needed to carry out the demands of your program. That's a quality you just don't find in ordinary personal computers. And it's one of the reasons some computer experts say that ATARI computers are so far ahead of their time. There's more... which is what you'd expect from ATARI.

Sound. An ATARI computer has four sound

ATM Oar -

_a.,ar.O°>..

Language. The ATARI Personal Computer uses several programming languages to give the user maximum control of its extraordinary capabilities. PILOT Microsoft BASIC,* and ATARI BASIC are understood and spoken by the ATARI computer. You'll also find our Assembler Editor cartridge indispensable for machine language programming.

generators, or voices, actovated by a separate microchip. This leaves the principal microprocessor chips free to perform other tasks. And you can take full advantage of this capability which is designed for easy programming. Change. ATARI Home Computers have been designed to make change and expansion easy. The ATARI computer has a modular operating system* that can be easily replaced as new technology develops. If you need it, memory expansion requires no more than inserting additional RAM modules* And the ATARI ROM cartridge system also makes it easy to change languages. In short, your ATARI computer won't be obsoleted by future developments... beause it already incorporates the future. Sharing. To learn more about the amazing capabilities of ATARI computers, visit your local computer store for a demonstration. Or send for our Technical User's Notes, intended for the serious programmer. They are only $27 and contain a lot more information about our computers' special capabilities than most companies could tell. See your ATARI dealer, or send $30 ($27 plus $3 postage and handling), payable to ATARI, to Technical User's Notes, c/o ATARI Customer Service, 1340 Bordeaux Avenue, Sunnyvale, CA 94086.

*ATARI 800'" computer only.

ATARI ©1981

Atari, Inc.

©

A

Warner Communications Company

CIRCLE NO. 59 ON FREE INFORMATION CARD

,

ang°Model 91C85 19"Color TVRecei ver

The Sanyo 91C85 is a 19" table-top

color receiver with an 82- channel varactor-controlled tuner that is simple, yet elegantly designed. With it, the viewer can precisely adjust each channel frequency via a control assembly mounted behind the front panel. Any 12 channels (both uhf and vhf) can be programmed into the illuminated front -panel selector and then accessed directly by UP /DOWN pushbuttons, or with a wireless remote control. Another front -panel feature is Sanyo's "Trimatic" color control. It consists of three pushbuttons that, respectively, set the TINT /COLOR, BRIGHTNESS/CONTRAST, and automatic fine tuning (AFT).

Otherwise,

the

front

panel

is

sparse -with VOLUME/ON being the only additional control. The 91C85's remote control is similarly clutter free- containing only one channel selection, VOLUME UP/DOWN, and POWER ON /OFF buttons. The set's dimensions are 171/4"H by 24'/2" W by 181/2"D. Suggested retail price, including remote control, is $540.

General Description. The Model

91C85 contains five pc boards, two of 20

which are mounted back-to- back -performing the channel selection, remote control, and vhf/uhf tuning. All of the i -f, video, audio, and deflection circuitry is contained on the main signal circuit board, which is mounted horizontally below the picture tube. A small pc board, about 2" by 2 ", houses the three front panel pushbutton switches that select manual or automatic control of aft, tint /color, and brightness /contrast. A sixth pc board (part of the picture tube socket assembly) contains all the amplifier adjustments for red, green, and blue video output. The outer sleeve of the tuner (Fig. 1) controls a three -position switch corresponding to the frequency range of the associated channels, i.e., VHF LOW, VHF HIGH, and UHF. The tuner's inner shaft operates the fine- tuning potentiometer. Next to each display window is a light that illuminates the particular channel you are watching. The two pushbuttons controlling the UP /DOWN channel selection operate via the Mitsubishi IC16O1 shown in Fig. 2. This chip accepts commands to step its four -bit ring counter up or down. The counter responds with a binary signal,

which is then decoded and translated into a precise voltage that tunes in the channel you have selected. The remote control sends out an ultrasonic signal that is decoded at the receiver by another IC (not shown). The up/down signals coming from this IC are then processed by IC16O1, just as if they had come from the set's UP /DOWN pushbuttons on the front panel. Other important technical features include the SAW (Surface Acoustic Wave) filter, which eliminates the need for additional i -f alignment, and the use of automatic control circuits for chrominance phase angle, determination of fleshtones, and proper video levels. A power IC provides dc regulation for the 123 -V B+ line. The three low -voltage dc sources (one 15 -V and two independent 12 -V sources) are derived from the flyback transformer. Each voltage is regulated by a zener diode. A single IC provides the sync separation, noise cancelling, and the vertical and horizontal sweep signals. Two transistors are used in the horizontal flyback, and three transistors perform the vertical output amplification. The 28 -kV high -voltage supply is rectified by a conventional three -diode POPULAR ELECTRONICS

RADAR WARNING RECEIVER

What makes this radar detector so desirable that people used to willingly wait months for it? Anyone who has used

a conventional passive radar detector knows that they don't work over hills, around corners, or from behind. The ESCORT" radar warning receiver does. Its uncanny sensitivity enables it to pick up radar traps 3 to 5 times farther than common detectors. It detects the thinly scattered residue of a radar beam like the glow of headlights on a dark, foggy road. You don't need to be in the direct beam. Conventional detectors do. Plus, ESCORT's extraordinary range doesn't come at the expense of more false alarms. In fact, ESCORT has fewer types and sources of false alarms than do the lower technology units. Here's how

of speaking with the most knowledgable experts available and saving us both money at the same time. Further, in the unlikely event that your ESCORT ever needs repair, our service professionals are at your personal disposal. Everything you need is only a phone call or

parcel delivery away.

r

Carrying case and visor clip included

we do it.

The unfair advantage ESCORT's secret weapon is its superheterodyne receiving circuitry. The technique was discovered by Signal Corps Capt. Edwin H. Armstrong in the military's quest for more sensitive receiving equipment. ESCORT's Varactor -Tuned Gunn Oscillator singles out X and K band (10.525 and 24.150GHzi radar frequencies for close, careful, and timely examination. Only ESCORT uses this costly, exacting component. But now the dilemma.

The right stuff ESCORT looks and feels right. Its inconspicious size (1.5H x 5.25W x 5D), cigar l ig hter power connector and hook and loop or visor clip mounting make installation easy, flexible, and attractive. The aural alarm is volume ad-

justable and the alert lamp is photoelectrically dimmed after dark to preserve your night vision. And, a unique city /highway switch adjusts X band sensitivity for fewer distractions from radar burglar alarms that share the police frequency while leaving K band at full strength.

Another nice thing about owning an ESCORT is that you deal directly with the factory. You get the advantage

know which one you'll keep. As further insurance for your investment, ESCORT comes with a full one year limited warranty on both parts and labor. This doesn't worry us either because ESCORT has a reputation for reliability. We know that once you try an ESCORT, radar will never be the same again. So go ahead and do it. Order today.

You don't have to wait Just send the followinc to the address below: Your name and complete street address. How many ESCORTs you want.

"s" Corroborating evidence

...

"Ranked according to perforCAR and DRIVER mance, the ESCORT is first choice it looks like precision equipment, has a convenient visor mount, and has the most informative warning system of any unit on the market the ESCORT boasts the most careful and clever planning, the most pleasing packaging, and the most solid construction of the lot' BMWCCA ROUNDEL "The volume control has a 'silky' feel to it; in fact, the entire unit does. If you want the best, the is it. There is nothing else like it." PLAYBOY "ESCORT radar detectors (are)

...

...

...

...

...

generally acknowledged to be the finest, most sensitive, most uncompromising effort at high technology in the field." PENTHOUSE ... " ESCORT's performance stood out like an F -15 in a covey of Sabrajets:' AUTOWEEK... "The ESCORT detector by Cincinnati Microwave is still the most sensitive, versatile detector of the lot"

...

The acid test Made in Cincinnati

of your choice. Test them both for 30 days and return the one you don't like. We're not worried because we

Any special shipping instructions. Your daytime telephone number. A check or money order.

The Lady or The Tiger At the instant of contact. how can you tell a faint glimmer from an intense radar beam? Is it a far away glint or a trigger type radar dead ahead? With ESCORT it's easy: smooth, accurate signal strength information. A soothing, variable speed beep reacts to radar like a Geiger counter, while an illuminated meter registers fine gradations. You'll know whether the radar is miles away or right next to you. In addition, the sound you'll hear is different for each radar band. K band doesn't travel as far, so its sound is more urgent. ESCORT keeps you totally informed.

your purchase as well as pay for your postage costs to return it. In fact, try an ESCORT and any other detector

There's only one way to really find out what ESCORT is all about. We'll give you 30 days to test it for yourself. If you're not absolutely satisfied, we'll refund

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video ,m111111

SANYO MODEL 91C85

CONTROLS CHANNEL PRESET BRACKET AND TUNER BOARD CIRCUIT BOARD HOLDER

CHANNEL SELECTION, MEMORY AND REMOTE CONTROL BOARD CHANNEL SELECTION TOUCH PLATES

PRE-SET CONTROLS

INNER -FINE TUNING OUTER-BAND SWITCH

Fig.

1.

A cut-away view of the tuning control.

series arrangement on the high -voltage flyback winding.

Laboratory Tests. We tested the unit as we received it-right out of the factory sealed carton. Test results are summarized in the Table. During testing, all r-f signals were supplied to the set through its 300-ohm antenna input terminals. Vhf and uhf tuner sensitivity (30µV at 66.0 dBm, and 38 µV at 63.5 dBm, respectively) reflect the high performance of both the tuners and their r-f-input circuits. Similarly, the noise figures at the video detector (10 dB for vhf and 16 dB for uhf) mean a clear picture without "snow" for the viewer. (Truly excellent noise figures would be somewhat lower -say, 8 dB for vhf; 12 dB for uhf-but this set's performance is about as good as any in its price range.) A video bandwidth of 3.55 MHz, measured at the video detector, is wide enough to give a sharp picture with good detail. To quantify picture "sharpness" we adjusted the high- frequency portion of the video signal between the video detector and the CRT with the sharpness control. At the maximum sharpness setting (Fig. 3), the video response is rolled off 3 dB at 3.6 MHz, and very little "overshoot" (silhouettes around the image edges) is apparent. By way of comparison, the minimum sharpness setting (Fig. 4) rolls off the video response 3 dB at 3.45 MHz, producing a picture with much softer definition. A similar, but less subjective test involved the use of a color -bar generator. Figure 5 shows the color -bar pattern at the video input, and Fig. 6 shows its appearance at the first video amplifier, after passing through the vhf tuner and detector section. Not the slight overshoot due to the peak in the high- frequency response. Whereas the pattern appeared virtually undistorted when the sharpness 22

19" COLOR TV RECEIVER

LABORATORY DATA

-17.2 dBmV -14.7 dBmV

Sensitivity, vhf (Ch. 2): Sensitivity, uhf (Ch. 50): Noise figure, vhf (Ch. 2): Noise figure, uhf (Ch. 50): Overall video bandwidth: Tuner oscillator frequency stability: Horizontal nonlinearity: Vertical nonlinearity: Voltage regulation, 123 V dc: (105 to 130 V ac) Voltage regulation, 28.5 kV: (105 to 130 V ac + min. /max. brightness and contrast Dc restoration:

10 dB 16 dB

3.55 MHz ±0.35 MHz; 90% 2% left, 1% right 1% top, 0% bottom

96% 90% 98%

The regulation of the high -voltage power supply was similarly tested at various line voltages and at different levels of brightness and contrast. We found a drop of approximately 10% when the line voltage was at its minimum and the brightness at its maximum setting. There was, however, no "blooming" of the color picture. Interference on channel 2 was barely noticeable with a 4 -W citizen's band transmitter (28 MHz) radiating just 60 feet away from the TV set. The vhf tuner's 300-ohm input contains a high -pass filter which, together with the 300/75 ohm balun helps to keep such interference to a minimum. Airplane flutter, too, is minimized by an automatic gain control (agc) that uses a multiple -stage r-c circuit. Thus, when a plane is overhead, amplitude distortions in the r -f and i -f signals are compensated by a stage with a short time constant. As the aircraft reflection fades, the longer time constants compensate. Dc restoration is close to 98 %, and is provided by the same circuit that adds the Y signal to the RGB output. This produces very vivid, pure colors. Finally, the simple 3" by 5" oval speaker was found to produce adequate, ordinary TV audio.

control was set to minimum sharpness, vertical white lines, indicating overshoot, appeared when this control was set for maximum sharpness. The stability of the tuner's local oscillator was tested over a period of six hours, with line -voltage variations between 105 and 130 V ac, and the set's automatic fine tuning (aft) disabled. Under all conditions, the oscillator response was within 0.35 MHz of the exact frequency needed to receive a particular channel. Horizontal and vertical nonlinearity were also measured over a six -hour period, using a raster format. We measured the width and height of the squares at the far left, right, top, and bottom of the screen, and compared them with a square at the center. The horizontal discrepancy was 2% on the left, 1% on the right. Vertical discrepancy was 1% at the top, and 0% (undetectable) at the bottom. In other words, image distortion (pin- cushioning) is negligible at the edges of the screen. Convergence was a comparably excellent 99 %. Reds, greens, and blues are clear and undiluted. The 123 V from the dc power supply was found to vary no more than 4% over the 105 to 130 V ac range. IC1601 22

21

20

19 LOCK

3-BIT RING COUNTER

18

17 FC:DEFEA

15

16

14

,7

-12

10

11

GATE

DECODER

111111111 INITIALLIZER

4 -BIT RING COUNTER

Fig. 2. The Mitsubishi 1C1601 controls channel selection. POPULAR ELECTRONICS

video Comments. The electronic performance tests verified what we saw: The Sanyo Model 91C85 produces excellent color pictures with strong, pure reds, greens, and blues. Depending on the brightness/ contrast setting, however, pastel colors were sometimes suppressed, making some nature scenes appear unnaturally bright. While the varactor tuner in the set we tested may not have been aligned for its maximum sensitivity and noise performance (our measurements of these parameters fell a bit short of Sanyo's specs), the receiver still worked quite well, even in fringe reception areas. We were particularly impressed with the stability and accuracy of the tuner oscillator, and found that the deflection circuits produced a very linear, well- converged color picture. The electronic tuning section functions as designed, though not including the 23 midband and superband cable channels may be a very minor drawback for some people. (Sanyo's 91C89 includes this feature, as well as a few others for $89 more.) All -in -all, we found this to be an excellent 19" color set, with a well- engineered chassis, simple, reliable circuitry, and ac-

cessible

servicing.

test

-points

for

Fig. 5. Color-bar signal at the video input.

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Fig. 6. Color-bar signal at first video amp.

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Fig. 3. Max. sharpness shows overshoot.

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Fig. 4. Min. sharpness shows scfter detail.

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JULY 1982

23

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ns

electronic is no picnic.

At any level it

takes work and a few sacrifices. But with CIE, it's worth it. 24

POPULAR ELECTRONICS

Whoever said, "The best things in life are free :' was writing a song, not living a life. Life is not just a bowl of cherries, and we all know it. You fight for what you get. You get what you fight for. If you want a thorough, practical, working knowledge of electronics, come to CIE. You can learn electronics at home by spending just 12 hard -working hours a week, two hours a day. Or, would you rather go bowling? Your success is up to you. At CIE, you earn your diploma. It is not handed to you simply for putting in hours. But the hours you do put in will be on your schedule, not ours. You don't have to go to a classroom. The classroom comes to you.

Why electronics training? Today the world depends on technology. And the "brain" of technology is electronics. Every year, companies the world over are finding new ways to apply the wonders of electronics to control and program manufacturing, processing... even to create new leisure -time products and services. And the more electronics applications there are, the greater the need will be for trained technicians to keep sophisticated equipment finely tuned and operating efficiently. That means career opportunities in the eighties and beyond.

facts about circuits and transistors. Electronics is interesting! It is based on recent developments in the industry. It's built on ideas. So, look for a program that starts with ideas and builds on them. Look to CIE.

Programmed learning. That's exactly what happens with CIE's Auto -Programmed® Lessons. Each lesson uses famous "programmed learning" methods to teach you important principles. You explore them, master them completely, before you start to apply them. You thoroughly understand each step before you go on to the next. You learn at your own pace. And, beyond theory, some courses come fully equipped with electronics gear (the things you see in technical magazines) to actually let you perform hundreds of checking, testing, and analyzing projects.

Experienced specialists work closely with you. Even though you study at home, you are not alone! Each time you return a completed lesson, you can be sure it will be reviewed, graded and returned with appropriate instructional help. When you need additional individual help, you get it fast and in writing from the faculty technical specialist best qualified to

Which CIE training fits you? Beginner? Intermediate? Advanced? CIE home study courses are designed for ambitious people at all entry levels. People who may have: 1. No previous electronics knowledge, but do have an interest in it; 2. Some basic knowledge or experience in electronics; 3. In -depth working experience or prior training in electronics. You can start where you fit and fit where you start, then go on from there to your Diploma, FCC License and

answer your question in terms you can understand.

CIE prepares you for your FCC License. For some jobs in electronics, you must have a Federal Communications Commission (FCC) License. For others, some employers tend to consider your license a mark in your favor. Either way, your license is government -certified proof of your knowledge and skills. It sets you apart from the crowd. More than half of CIE's courses prepare you to pass the government administered exam. In continuing surveys, nearly 4 out of 5 graduates who take the exam get their licenses! You can be among the winners.

Associate Degree Now, CIE offers an Associate in Applied Science Degree in Electronics Engineering Technology. In fact, all or most of every CIE Career Course is directly creditable towards the Associate Degree. Today is the day. Send now. Fill in and return the postage -free card attached. If some other ambitious person has removed it, cut out and mail the coupon. You'll get a FREE school catalog plus complete information on independent home study. For your convenience, we'll try to have a CIE representative contact you to answer any questions you may have. Mail the card or the coupon or write CIE (mentioning name and date of this magazine) at: 1776 East 17th Street, Cleveland, Oh' 44114.

career.

Pattern shown on

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computers.__

Popular Electronics Tests

Systems Group Model2829Microcomputer MODERN microcomputer systems are exhibiting great computing power and functionality unimagined only a few years ago. One such product is the Systems Group's Model 2829. Priced at $9565, the basic system comes with 128K bytes of RAM, four serial and two parallel I/O ports, one double -sided floppy, and one 10M -byte hard disk. Among the software available are MP /M 1 at $435, MP /M II at $585, and Oasis at $995. CP /M comes as standard equipment. Characterized by its manufacturer as well -suited for business, industry, and educational needs, the Model 2829 is in many ways the most powerful system we have tested to date. But don't let sheer power fool you: we found some questionable items that have to be considered before an investment in a system like this is justified. The Micro That's a Mini. The 2829 is unlike any other system we've reviewed since it couples Winchester storage with

multi -user /multi -tasking capability. Moreover, the 2829 should be considered a minicomputer simply because it offers 28

the computing functionality of much larger machines. This computer uses a 4 -MHz Z80A microprocessor and is built around an 8slot, S -100 bus motherboard that meets IEEE 696.1/D2 conventions. Meeting these conventions implies that the system can handle 8 -bit and 16 -bit processors while allowing master /slave bus operations-something that this particular manufacturer hasn't taken full advantage of. The heart of the system is the Model CPC-2810 processor board -which includes the Z80A, four serial ports, two parallel ports, a real -time clock, and a vectored interrupt structure. Working in conjunction with the processor board are two Model 0M6400, 64K -byte bank selectable dynamic memory boards for single- or multi -user applications. In addition, the System 2829 includes a Memorex 101 Winchester 10M -byte drive and a Model FD1 160 double density /double -sided floppy capable of 1.2M bytes of storage. Interestingly, the Memorex drive is being replaced with Fujitsu or Quantum drives. This is because the Memorex

drives have exhibited reliability problems, and are of limited capacity. Also, since many system designers experienced difficulties with the original Memorex drive, even Memorex has abandoned the design in favor of the Fujitsu product. The 2829's floppy disk system is supported by the Model FDC -2800 floppy disk controller, that has onboard sector buffering and full direct memory access (DMA) functionality. This card uses the NEC -765 controller in concert with a Z80A DMA chip. The Model HDC -2800 hard disk controller from Morrow Designs can control up to four daisy chained Winchesters. Although the processor board has both serial and parallel ports, all interfacing to the outside world is handled via personality modules that are mounted on the back panel. The Supply That Protects. In the case of a high -performance microcomputer, the power supply not only provides system power but also serves to protect the system against loss of power due to power-line surges. The 2829 system's supply is a linear design that provides unregulatPOPULAR ELECTRONICS

computers ed voltages of 8 V at 16 A, ±16Vat2.5A, and exhibits a 20 -ms holdup time after removal of ac power. The regulated portion of the supply is 5 V at 5 A, 24 V at 5 A, and 5 V at 1 A.

-

The power is tied to the motherboard midway in the bus structure. This is important to ensure that sufficient power is provided to all boards on the bus factor frequently forgotten by many S -100 bus system designers. In conjunction with the power supply, there are two unfused convenience outlets located on the rear panel of the enclosure. These can be used to provide power to printers, terminals, modems, etc. However, care must be taken to ensure that the maximum switched load never

-a

exceeds 9 A. The power -supply system also allows either 115 V ac or 220 V ac to be used, and features a Ht /tow switch for operation with less- than -predictable local power sources. System cooling is accomplished via a rear-mounted fan. This fan provides a Venturi effect, moving hot air up and away from the lower component areas while circulating air over the card rack

is

diskette is placed in the floppy drive, the system boots from it; otherwise a boot takes place off the hard disk system. Once booted under MP /M, we formatted the hard disk-the operating system takes into account any premapped defects and locates others, mapping them into the BDOS and directing the system to reserved tracks. The version we booted allows the use of both the floppy and the hard disk, and only one console. The system we transferred to the hard disk supports three consoles and a printer. (You can establish up to 14 consoles, but you have to. "grow" the system in terms of memory and I/O modules.)

Hardware Evaluation. In the case of the motherboard, the designers followed current conventions by providing passive termination, ground planes between the signal paths, and full power grounds. Scope tests of the board, with the processor performing transfers between the disk controllers and memory, showed no crosstalk or ringing. Other signals were clean square waves without "rounding" or degraded rise time due to board capacitance.

Using an 8-slot motherboard, a hard -disk controller combined with a floppy controller having DMA capability.

and past the disk systems before exhausting it. Fresh cool air is brought in via a filter on the front panel.

What We Tested. The system we evaluated consisted of a 10M-byte Winchester, 1.2M -byte floppy, 128K-byte dynamic memory, and four serial ports with I/O personality cards. There was no parallel

port implementation. Everything is

housed in a very sturdy metal enclosure that requires only sliders to be added to fit in a standard 19 -in. RETMA rack. As shipped, three ports -0, 1, and 2-came configured at 9600 baud for terJULY 1982

minal operation and the fourth port (3) was configured for printer operation at 300 baud. Our model employed the serial ports as dual asynchronous receiver transmitters. We could have requested synchronous I/O (SIO) ports-an option available at additional cost. To bring the system up, we attached a MicroTerm ACT 1A CRT, configured for 9600 baud on port 0. We then booted CP /M from the distribution diskette, as suggested by the documentation. We used this for initial system checkout to determine if the system did, in fact, sign on -which it did, with a fair amount of speed. Unlike other formats that store the CP /M system on the reserved tracks of the diskette, the Systems Group stores CP /M as two files-CPSYS.SPR and CBIOS.SPR. The first contains Digital Research's Console Control Processor (CCP) and BASIC Disk Operating System (BDOS) modules in their pagerelocatable format. A loader, provided by the manufacturer, is used to load these files and execute them, thus speeding up system operation. This precludes reloading the CCP on warm boots: a jump to lo-

cation zero is effected instead, and a disk reset is performed. Using this technique, one version of CP /M fits any memory size. In addition, since reserved tracks aren't used, you can add additional drivers to CP /M without worrying about running out of space to store the system. We liked this since it meant we didn't have to SYSGEN each diskette. Once we were assured that the system did, in fact, operate, we then re-booted using MP /M 1.1. Booting takes place either at power on or by depressing the front panel RESET switch. When a

We like the diagnostic LEDs on the CPU and memory boards that advise when a segment is being used and for how long. We "fooled" the machine by partly disabling a segment (a 16K-byte block) to force an error. This error was then easy to locate using the LEDs. Although the power supply does have fold -back time in case of power failure, the 2829 does not employ this feature to automatically save any data currently in memory. However, fold -back time is used to prevent a hard -disk crash since sufficient time exists to pull the head back from the media. 29

I

MOST PERSONALCOMPUTERS CAN'T COPE WITH IMPLE ADDITION. Because most PC's use their expansion slots fer both added memory and peripheral interfaces, you may be forced to choose one or the other. Add memory, lose peripherals.

And vice versa. The Apple III was designed with an array of built-in connectors and interfaces that leave you room to grow, even when you upgrade to maximum RAM. Take a bottoms -up tour of the opposite page, ar:d consider the possibilities. The Apple III Itself. Its standard 128K RAM is twice what some of the most powerful PC's offer as standard. Upgrade to a maximum 256K RAM, and you've still got four unused expansion slots. Disk III Drives. Daisy -chain up to three of them with the Apple III's built -in drive, right through a back panel connector, for a total of 560K floppy disk storage.

Our new ProFile:" Mass storage made personal with a very quick, very quiet 5 -Mb hard disk. Ideal for software development or data base applications. Monitor. Shown is our standard Monitor III with its crisp green phosphor display. But the Apple III can drive any popular black and white or color monitor. 16-color graphics capability is standard.

Personal Printer. Very affordable, virtually noiseless, and perfect for rough copy, B&\V graphics and quiet offices. SilentypeTM

Letter Quality Printer. For proessional caliber word processing with Apple Writer III software.The Apple III can drive virtually any printer in any task, from preparing reports to printing forms. Color Plotter.To make the colorful most of the Apple III's high res graphics in charts, graphs and designs. Phone Modem. Which, with Access III asynchronous communications software, lets you communicate with other PC's or with mainframes at up to 9600 bps. Only the Apple III can handle all of the above, all at once, without losing i:s memory. And even though you may never configure your system just like this, its important to know how far you can grow. With a couple of OEM Prototyping Cards. Or your own specialized peripherals. Or future technology. See your autZorized Apple dealer for a spec -to-spec comparison of the Apple III and the most muscular new PC's. You'll find that, even with 256K, most of them just can't stack up.

The personal computer.

pPPIC

Call 800. 538.9696 (in California, call S00-662 -92381 for the authorized Apple dealer nearest you, or for information on our National Accounts Program. Or write: Apple Comptmer Inc Ac ve-tising and Promotion Dept 20525 Marian Ave.. Cupertino, CA 95014. NOTE: Apple Computer does not currently manufacture or ,

distr;bute color monitors, graphics plotters or telephone modems Apple

is a

registered trademark of Apple Computer Inc.

CIRCLE NO. 9 ON FREE INFORMATION CARD

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computers We rated the hardware very good, and found the design conservative and straightforward in its handling of the bus and processor. The only serious hardware fault we found involves the front -panel air filter. For this class (and price) of system we expected a form -fitted, fiber -glass design.

ELECTRONICS TECHNICIAN COMPUTER PROGRAMMER TELECOMMUNICATIONS INSTALLER TECHNICIAN ELECTRONIC EQUIPMENT SERVICEMAN CABLE TV INSTALLER

NEW

-

Fiber Optics

The Software Key. As stated earlier, the system was set up for operation under MP/M 1.1 with three consoles and one serial printer. Implementing MP/M was easy since the Systems Group had done all the work; we merely moved it to the hard disk. Unfortunately, with this implementation you either operate with floppy disk and hard disk, and one console, or have just the hard disk available to several users. This is because MP /M requires that the floppy-driver area be made to support user maps. MP /M II takes care of this problem, and with a properly written BIOS (called an XIOS in MP /M) will give the best of both worlds. Among the first tests we performed was our obligatory speed test in BASIC. Here we use 10 GOSUB 10, which pushes all the memory contents onto the stack until an error is generated. In the case of the 2829, the time needed to produce an error was 0.1 second (average) out of ten trials. A real challenge came with the compiling of Digital Research's chess program, written in PL/I. We used three minutes as our benchmark, as measured on an Altos 4 -MHz system. In the case of the 2829, we came up with 110.4 seconds for ten trials. This included compiling, linking, and loading the code. The test was also performed using CP/M. At least 56K bytes of memory is required, and MP /M restricts you to 48K. We performed the first trial using the hard disk system, but also achieved high throughputs on the floppy system. It was slower, but still took only 2.05 minutes. The timing for this task is significant because the compiler first had to be read in, next the code (or segments to be compiled) was read in, then internal comparisons were made to tables and library functions used, and finally the code written back out. Because the manufacturer touts the 2829 as ideal for multi users, we attached three terminals and a printer for a full configuration. Our first task was to go in and PIP (move) a 128 -entry directory from user-0 to several user areas on the disk (you have a total of 16 user areas per logical disk). By setting up for automatic operation, and causing operations to take place between several areas at the same time, we were able to exercise the hard disk to its maximum. Part of this test included setting the time, using the time -of-day function in MP /M, and printing it out every minute. Our next step was to perform several tasks on the system simultaneously. We asked console 1 to use user -0 and play chess. Then we instructed console 2 to set up an assembly in user -1, which we then made a background operation by employing the MP /M detach command (invoked by entering a control D from the keyboard). This freed console 2 for other operations. We also set up a spooling operation of a previously large text in user -2 and began a text -editing project in user -3. Meanwhile, console 3 was used as a general purpose utility port to monitor all system operations and slide in and out of the other areas. We found little or no degradation of operations, except when console 3 invaded another console's user space (this is a shortcoming of MP /M 1.1 that has been taken care of in MP /M II).

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Some Critical Thoughts. Undoubtedly the 2829 is powerful. But this power brings some new headaches, requiring that you go through a relearning process. For example, a "console" is different from a "user." The console is the physical device connected to a physical port, the user is the area on a disk that the console is allowed to use for handling data. These user areas can be public or restricted- making difficult your first implemen(Continued on page 34) tations of MP /M.

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Reduced Member Prices. Save up to 75% on books sure to increase your know-how Satisfaction Guaranteed. All books returnable within 10 days without oblügation Club News Bulletins. All about current selections- mains, alternates, extras -plus bonus offers. Comes 13 times a year with dozens of up- to-the- minute titles you can pick from "Automatic Order." Do nothing, and the Main selection will be shipped automatically! But ... if you want an Alternate selection -or no books at all -we'll follow the instructions you give on the reply form provided with every News Bulletin Continuing Benefits. Get a Dividend Certificate with every book purchased after fulfilling membership obligation, and qualify for discounts on many other volumes Bonus Specials. Take advantage of sales, events, and added -value promotions Exceptional Quality. All books are first-rate publisher's editions, filled with useful, up- to-the-minute info

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Please accept my membership in Electronics Book Club and send the 6 volumes circled below. I understand the cost of the books selected is $2.95 (plus shipping/handling). If not satisfied, I may return the books within ten days without obligation and have my membership cancelled. I agree to purchase 4 or more books at reduced Club prices during the next 12 months, and may resign any time thereafter. 334 829 841 1062 1076 1113 1123 1138 1169 1211 1218 1233 1245 1249 1277 1278 1291 1299 1306 1316 1321 1333 1367 1370 1397 1409 1416 1417

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CIRCLE NO. 45 ON FREE INFORMATION CARD

PE-782

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Add a dbx Model 22 Auto Decoder to a quality auto sound system. You'll get the ultimate in auto sound when you play dbx encoded cassettes. The excitement of full dynamic range. Better than twice the noise reduction of a Dolby C "-type noise reduction system. All the music you'd hear at home, in fact. If you lived in Carnegie Hall.

Dolby CL" is a registered trademark of Dolby Laboratories Licensing Corporation.

6x:Musiccaiitlivewitho dbx, Inc., 71 Chapel St., Box 100C, Newton, Mass. 02195 U.S.A. Tel. (617) 964-3210, In Canada: BSR (Canada) Ltd. CIRCLE NO. 15 ON FREE INFORMATION CARD

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Although the system's power supply is quite good, it doesn't fully protect against power surges or dropouts. In one case, for instance, it allowed the floppy disk head to bang, causing a misalignment to which some NEC-type floppies are prone. We really like the fact that the floppy system didn't care about diskette data density or format could read anything except diskettes formatted on a California Computer Systems controller. We would have preferred an MP/M implementation allowing all consoles and the floppy system to be used at the same time. We don't believe the business user will want to change disks to get the system into another configuration. The docutnentation supplied is very good. Its technical content is among the best offered by any computer company. Information for reconfiguring is readily available, with sufficient details so that code can be quickly modified. However, there is very little here directed at the casual user (no manual). Most of the information is for the system integrator or computer store. According to company officials, this will be remedied, probably by the time you read this review. The Systems Group went through a great deal of effort to implement the 2829's operating systems so they would be useful. Unfortunately, by planning to implement operating systems like Oasis, rather than sticking with well- supported systems, their efforts are diffused. And since the 2829 is aimed at business and industrial applications, it would be a plus if the System's Group would offer cornmunications packages such as the Remote Terminal Batch Emulator that Lifeboat Associates provides for IBM communications. (A company spokesman did report that the Systems Group is planning to add networking capability, plus the ability to pool resources from remote locations, later this year.)

.

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'2.49 '2.95 '2.37

'449 '1.23 '2.49 '3.29

Conclusions. The Model 2829 is only one of several 2800-series configurations available from the Systems Group. We found it to be highly reliable, well built,

and meeting all the specifications claimed by the manufacturer. We didn't feel, though, that it offered anything unusual relative to other computing systems in its class. Where software is concerned, Oasis, though a very fine operating system, isn't as heavily supported as CP /M or MP/M. And those Oasis packages that are offered often carry a high price tag. So keep this in mind. We'd advise that you bypass MP/M 1.1 and get MP /M II, but be careful on the implementation.

-Carl

Warren

CIRCLE NO. 102 ON FREE INFORMATION CARD CIRCLE NO. 27 ON FREE INFORMATION CARD

34

POPULAR ELECTRONICS

HEATH /ZENITH &YOU... ONE STRONG PARTNERSHIP. Buying a computer is only the beginning of a long -term partnership between you and the people from whom you buy. Your ongoing need for software, peripherals and accessories requires a partner who will stand by you. With a growing line of products to meet your needs with professional service and support, Heath/Zenith is that strong partner. Look at what we have to offer:

THE ALL -IN -ONE COMPUTER - The heart of the Heath/ Zenith line is the stand -alone 89 Computer. It's a complete system with built -in 5.25-inch floppy disk drive, professional keyboard and keypad, smart video terminal, two Z-80 microprocessors and three RS -232C Serial I/O Ports. It comes with 48K bytes of RAM, expandable to 64K.

OPERATING SYSTEMS -Three versatile systems give you the capability to perform your specific tasks. CP /M by Digital Research makes your system compatible with thousands of popular CP /M programs. UCSD P- System with Pascal is a complete program development and execution environment. And HDOS, Heath Disk Operating System gives you a sophisticated flexible environment for program construction, storage and editing. DISK SYSTEMS -The new Heath! Zenith 67 Winchester Disk System, for commercial use, adds nearly 11 megabytes of storage to your 89 computer. It includes an 8 -inch floppy disk drive for data portability. The new 5.25 -inch 37 disk system, available with 1 or 2 drives, adds up to 1.28 megabytes of storage. Both plug -in systems have write protection.

PERIPHERALS AND ACCESSORIES -These include the popular Heath/Zenith 19 Smart Video Terminal, loaded with professional features. We also offer color and black and white monitors, modems, computer language courses, and high -speed

typewriter -quality printers.

406

-

SOFTWARE Our complete library of software includes the SuperCalc Spreadsheet and Condor Data Base Management System. Word processing, includes three different programs. Small Business Programs feature Peachtree's P5 Series, General Ledger and Inventory Control. HUG, Heath Users' Group, offers members a library of over 500 low -cost programs for home, work or play.

PROGRAMMING LANGUAGES -To write your own programs, Microsoft BASIC (compiler and interpreter), FORTRAN and COBOL Languages are available.

-

APPLICATIONS SOFTWARE Expand the performance range of your computer with a broad selection of software, including the best of Digital Research and Micro pro as well as the complete line of SoftstuffîM products.

-

SERVICE AND SUPPORT- Prompt and professional service and assistance is available nationally through Heathkit Electronic Centers, Zenith Data Systems for commercial users or through Heath factory servicing and phone -in technical assistance. Complete, integrated computer hardware and software, designed to serve and grow with you that's what to look for in a strong partner. And with Heath /Zenith, you get it all.

-

Heath /Zenith computer products are

sold nationwide through Heathkit Electronic Centers (check your white pages for locations). For a FREE colorful full -line catalog, write: Heath Co., Dept. 010 -914, Benton Harbor, MI 49022.

HEATH /ZENITH Your strong partner

Product specifications are subject to change without notice. Heath Company and Veritechnology Electronics Corporation are wholly -owned subsidiaries of Zenith Radio Corporation *Heathkit Electronic Centers are operated by Veritechnology Electronics Corporation CIRCLE NO. 22 ON FREE INFORMATION CARD

JULY 1982

CP-210R1 37

Popular Electronics JULY 1982

PE

COVRARS'

NEW HANDHELD COMPUTERS Author discusses results of his "hands on" experience with Sharp, Quasar, and H-P handhelds BY FORREST M. MIMS

TEN years ago, Hewlett- Packard introduced the HP -35, the world's first scientific calculator. Though some "experts" said its $395 price tag would hold little appeal for consumers, the company sold more than 300,000 units in the first three years. The HP -35 was certainly revolutionary for its time, but it was just another step in the evolution of handheld electronic calculating devices that still continues today. The most recent (and most impressive) products of this evolutionary process are a new generation of handheld computers. These new machines are not merely upgraded calculators. They are sophisticated, fully programmable computers with alphanumeric keyboards and displays. Their memory circuits retain data and programs even when the computer's CPU is powered down. They can be expanded with additional memory modules, and can be connected to peripherals such as printers and cassette -tape storage units. Handheld computers are much more "personal" than desktop personal computers owing to their small size and battery- powered portability. But are the new handheld computers practical? Are their prices, which can approach those of some desktop machines, justified? To answer these questions, a substantial amount of time was spent working with a handful of these units: Quasar's HHC (same as Panasonic's RLH- 1000), Sharp's PC -1500 (same as Radio Shack's TRS -80 Pocket Computer Model PC -2), and Hewlett -Packard's HP -41 Programmable Calculator. Each of these computers is unique. Here is a close look at their features, ca-

pabilities, idiosynchrasies, and peripherals.

38

Quasar HHC The Quasar HHC (Hand Held Computer) is a sophisticated portable computer with advanced programming features. A product of the Matsushita Electric Corp. of Japan, the HHC (as well as a Panasonic twin model) is compatible with a wide assortment of peripherals. The computer and its peripherals are distributed in the United States by the Quasar Co. (9401 W. Grand Ave., Franklin Park, IL 60131). The operating-system language is SNAP (derived from FORTH) or BASIC. The latter's thumb -size plug -in capsules give a choice of 8K Microsoft and 16K Level II BASIC. Moreover, CP /M software is said to be handled in conjunction with an HHC disk system. The HHC's microprocessor is a 6502 that operates at a clock speed of 1 MHz. The machine's internal ROM capacity is 16K bytes. In addition, a receptacle on the back side of the computer can accept up to three 16K-byte ROM modules. Each module is a plastic carrier containing a 22 -pin, dual -in -line ROM. Information in ROMs cannot be altered or erased, of course, so storage is needed to allow the user to store programs and data. The HHC's internal RAM is either 2K or 4K bytes (depending on the model). This can be expanded with as many as six 8K -byte nonvolatile (continuous storage), external memory units. The HHC has a typewriter -style (QWERTY) keyboard with 65 keys and two-key rollover. There is no numeric keypad; but an array of a dozen or so function keys, including a handy HELP key, are at the right side of the keyboard. The keyboard provides an automatic

repeat mode and full (up, down, left, right and stop) cursor control. Three keys are user definable. The individual keytops, all of which are colored gray, are not marked. Instead, their function or functions are printed in white and orange above each key. The display is a 26- character (8 X 159 dot matrix) liquid- crystal readout. Status indicators (SHIFT, LOCK, DELETE, etc.) are printed in a row under the display and, when selected, are indicated by a small triangle. The machine is powered by a built -in nickel- cadmium rechargeable power pack. The dimensions of the unit are 815/18" X 33/4" X 13/18 ". An important feature of the HHC is its user -accessible bus. Access to the bus is provided by a double -sided edge connector recessed into the left side of the case and containing 22 contacts on each side. A spring -loaded dust cover protects the connector when it is not in use. A wide range of compact peripherals can be connected to the HHC by means of its bus. Though it can function alone, the HHC can also act as the processor for a powerful computer system that fits in a slim -line attache case. The fully expanded attache -case system is a highly portable personal computing system that can be operated in a car, plane, or hotel room. For example, the Quasar handheld system reviewed here included the HHC, TV adapter, telephone modem, micro printer, RS -232 interface, and a programmable memory module. All these peripherals and the HHC slide into modular plastic trays attached to each side of the HHC's I/O (input /output) adapter unit. Up to six peripherals can be connected at a single time. The HHC can be connected via the TV adapter to an external color or B&W telePOPULAR ELECTRONICS

Counterclock awe from upper right: Hewiett- P'ckard AP --11, Radio Shack Tr S -30 DC -2 Quasar HHC, and Sharp PC-1500 with printer.

handheld computers The Quasar HHC telephone modem can be used in the field to access a

network or home -based computer.

vision receiver. This arrangement is particularly handy when developing programs or using the telephone modem to access another computer or one of the computer services. The HHC provides two video color graphics modes that display 64 dots by 32 lines or 64 dots by 48 lines in an assortment of black and eight colors. Sixteen lines up to 32 characters each can be displayed in various color combinations.

Using the HHC. Turn on most personal computers and the display typically shows READY, followed, perhaps, by a cursor. The HHC, however, provides an interactive series of nested menus that allow the user to select any of its various operating modes. When the machine is initially turned on, for example, the dis-

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40

POPULAR ELECTRONICS

play scrolls through the HHC's primary menu:

= = = = =

1

2 3 4 5

CALCULATOR CLOCK /CONTROLLER FILE SYSTEM RUN SNAP PROGRAMS MICROSOFT BASIC

Pressing converts the HHC into a low -grade, four -function calculator with a fully addressable memory. To return to the primary menu, the CLEAR key is pressed twice. 1

Pressing 2 causes the nested menus for the clock /controller to be scrolled through the display:

= 2 = 3 = 4 = 5 = 1

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MON 11:05:21

(very slow) to 0 (very fast). To load a BASIC program into the HHC, press 5 while the primary menu is scrolling through the display. This selects Microsoft BASIC. The display will then present a menu of programs already loaded in the HHC. If none are present, the display will show: 1

REVIEW ACKNOWLEDGE

If the time and date have already been set, select 4; the display will read something like:

= NEW

FILE

NO FILES

To enter a new program, press 1. The display will read PROGRAM NAME, followed by a blinking cursor. Type in a name, press ENTER, and the cursor alone will be displayed to indicate that program entry can proceed.

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A word of advice to first -time HHC users who know BASIC: The HHC requires an orientation period to fully understand its operation. Be sure to read through the owner's manual and Volume I of the Microsoft BASIC manual to learn the idiosyncrasies of this machine. If you don't, you may have considerable difficulty loading programs. For example, suppose you've figured out how to title a program, enter the title in the file menu, and write the actual program. Fine, but how do you return to the primary menu to select some other load another program? option Pressing CLEAR seems to be the logical move since this returns the primary menu to the display. But when you try to load a new program, the computer beeps and displays:

Pressing the i/o key will probably reveal a few thousand bytes of free internal RAM, so what went wrong? I attacked this problem without success until returning to Volume I of the Microsoft BASIC manual. Page 4 -8 warns "... you may be tempted to return from your program to the BASIC menu by pressing CLEAR, as you would do in most other HHC programs. Resist this temptation at all costs!" Later, on page 72, a way to recover from this keyboard gaffe is explained. So how should you return to the BASIC menu? As I noted earlier, just type BYE. Then press CLEAR to return to the primary menu. The lesson, then, is that when the cursor is blinking while the HHC is in program mode, never press CLEAR!

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components for the computers: (A) Quasar HHC; (B) Sharp PC -1500; and (C) Hewlett -Packard HP -41.

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menu). After you enter the program, type BYE to load it into the HHC. Should you make a mistake or wish to modify the program, the HHC has a very versatile array of edit functions. If you expand your filed programs to a point where less than 80 characters of storage remain, the display will warn:

i

A9 ACA 18

Your program name has now become part of the Microsoft BASIC menu and you need not assign it to a line number in your program. It is also listed in the file menu selection (key 3 of the primary

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The rate at which the HHC scrolls through the selections in its various menus can be controlled by means of the STP /SPD (stop /speed) key. Simply press STP /SPD, followed by any digit from 1

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9.8 SQUARED IS 81.0 10.0 SQUARED

IS 100.0

First-time users may also run into problems when attempting to use the HHC in its direct -execution or manual mode. The machine does provide a very limited four -function calculator mode, but more advanced operations involving more than simple arithmetic require BASIC. This means naming of a new program file or going to an existing program and using the computer in its direct -execution mode (that is, entering BASIC 41

handheld computers commands without line numbers). The existing program will be unaffected by what you enter. I much prefer the former method since it's easy to create (and thereafter select) a programless file named MANUAL MODE. Then you must learn how to enter commands. Suppose you want to know the square root of 743. You must place parentheses around the numerical value and enter PRINT SQR (743). PRINT can be abbreviated?. If you enter ? SQR 743, however, the HHC will beep and display SN ERROR to remind you to insert the missing parentheses. After figuring out this procedure, which is explained on page 2 -2 of Volume II of Microsoft BASIC, I tried to find the sine of 37° by entering ? SIN (37). A beep and a BS error promptly informed me something was wrong. This time the problem was more fundamental. BS is the error code for bad subscript, meaning an array element outside the dimensions of an array has been entered. Since the sine of 37° has nothing to do with arrays, I turned to the section on trigonometric functions in Volume II of Microsoft BASIC and read: "Microsoft Basic on the HHC does not have built -in trigonometric functions." Neither does the HHC have many other functions common to virtually all scientific calculators. Fortunately, appropropriate subroutines for sin, cos, tan, cotan and arctan are provided. These idiosyncrasies should not be considered deficiencies, for the HHC is apparently designed more as an information processor than as a high -powered mathematical machine. Of course, future ROM modules may add many more BASIC functions to the HHC. The HHC Micro Printer. Accessing the HHC's peripherals can be both awkward and tricky. For example, to use the miniature thermal printer, press the I/o key to check the printer's status. If no peripherals are connected to the bus, the display will show the available number of bytes in internal RAM. Otherwise, the display will identify, in turn, the name and status of each peripheral, as well as the amount of available RAM remaining in the HHC

and the programmable memory module (if connected). If the printer is in place, its status line may intially read: 1

= PRINTER OUT, OFF, SLOT =

3

OUT means the printer is an output peripheral, and OFF means the printer is now off. SLOT = 3 means the printer is plugged into slot 3 of the I/O adapter. (SLOT = 0 means the printer is plugged directly into the HHC's bus socket.) The printer is turned on by pressing 42

the digit key corresponding to its menu selection number (in this case, 1). The printer status line will then read: 1

= PRINTER OUT, ON, SLOT =

3

Using the printer requires the assignment of a logical unit number-LUN, for short -between the PRINT statement and the data to be printed. For example, in the statement PRINT #2; 123456, #2 is the LUN. Before this statement can be executed, the printer must be referenced via its identification number (68) to LUN

#2

with the ATTACH statement ATTACH 68 to #2. Now the printer will operate in response to the instruction PRINT #2; 123456 by printing 123456. ATTACH is a clumsy barrier to gaining access to the printer. However, it does provide an important advantage in program writing since programs can be peripheral independent. In other words, the same program can be used without modification to operate a printer or access some other output device. ATTACH defines which peripheral is accessed. This advantage notwithstanding, the HHC printer itself is the least sophisticated of the printer models reviewed here. Besides its rather noisy, raspy sound, printed lines are not visible by the user until the paper tape has advanced three or four lines. Quasar recognizes some of the limitations of the small HHC printer. The manual points out that a serial printer with an 80- character line width can be connected to the HHC by means of a serial- interface adapter. HHC Memory Modules. The plug -in

THE

BUTTERFLY"

1:REM

2:REM 3:REM

BUTTERFLY M1MS F. MARCH 3,

1982

5:LPRINT THE BUTTERFLY" ?:COLOR 03 .18 GRAPH 14:GLCURSOR (110, 100)

16:SORGN 17:LINE (0, 100)-( 25, 175)

18:LINE (0,100) -( -25, 175)

19:COLOR 00 20:LINE (5, 100)-(

21.COLOR 01 22:í0R A.=0T0 50 STEP 5 25:N=- 10 *SOR A 26:COLOR 01 30:LINE (0,100) -( N,

A)

40:NEXT A 42:í0R A =60T0 200 STEP 5 43.N=- 10 *SOR A 44.COLOR 02 45:LINE (0, 100)-( N,

A)

46:NEXT A 45: COLOR 01 50:P0ß 8 =0T0 50 STEP 60:0= 10 *SOR B 70:LINE (0,100) -( .5

0,8)

80:NEXT B 82:FOR B =60T0 200 STEP 5 83.0= 10 *SOR B 84:COLOR 02 85.LINE (0, 100)-( 0,

B)

86.NEXT 90:TEXT 100:END

B

Program and color graphics developed by the author for Sharp PC -1500.

memory modules contain either 8K or 16K of RAM, and batteries to keep the memory alive during power-off periods. There is one main slot for the memory module, though additional memory modules could be plugged into any of the other slots of the bus connector. In fact, an additional bus module could be connected by a cable and an additional six memory modules could be connected. However, the HHC can only address one memory module at a time (either 8K or 16K.) The other memory modules can be used to store programs or data that can be switched into use as required. Total memory capacity of the computer cannot be considered as contiguous blocks of addressable memory. Outside of one 8K or 16K block, the memory is the mass storage of this computer. Modem Module. The HHC Modem Module looks like any other coupler, but it is an unusual peripheral controlled by a replaceable ROM module. There are two such modules available for the modem unit. The first has a ROM called Telecommunications 1. It controls all of the protocol used in accessing public information networks like The Source or Compuserve. In use, all you have to do is make contact with one of these services and the modem provides all of the answers except your User Number and password. The other ROM is Telecommunications 2, and it contains programs to permit you to download or upload files from the host computer. Either of these ROMS enables a person with little experience to engage in network operation from his home. POPULAR ELECTRONICS

Introducing the Most Powerful Hand -Held Computer System Ever! Radio Shack's New TRS -80' Pocket Computer PC -2 And Printer /Plotter /Interface

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P

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Another Innovation Joins the TRS -60 Family -the Broaaest Line of Microcomputers in the World Radio Shack Introduces a New Dimension in Personal Computers: 21/16x 127/8x 41/2"-and that ineludes the printer! The new TRS -80 Pocket Computer Model PC -2 puts powerful computing features in the lands of engineers, students, businessmen, profes-

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to solve on- the-go.

Easy to Program. The PC -2 uses a powerful Extended BASIC language that permits program applications never before possible on a computer of this size. Loaded with Deluxe Features! The 26-character Liquid Crystal Display procuces upper and lower case characters, plus its 156 x 7 dot matrix is fully graphics programmable. Also included are 2640 bytes of user memory (retained when power is off), a 65 -key keyboard, 10-key nJmeric pad, a real time quartz clock, even a programmable beeper! Powered by 4 "AA' batteries ;not included). PC -2, Cat. No. 26 -3601.

Expand with 4 -Color Printing and Cassette Storage.

he

PC -2 Printer /P otter and Dual Cassette Interface (Cat. No. 26 -3605) makes it easy to plot superbly -detailed

XIY /Z graphics. Both upper and lower case characters can be printed in nine di=ferent sizes.

Dual Cassette Operation. Use two -ecorders to store and load PC -2 programs and data. Data can be read from one cassette, updated, and stored on 3 second cassette under program control automatically

-

Ready to Use. Just slip your PC-2 into the Printer /Cassette Interface. Its built -in rechargeable batteries also power the PC -2. Includes charger.

fleed more memory? .;ust plug in a 4K RAM Module Other nodules (for up to 8K) available soon.

See it in Action. The new PC -2 and Plotter /Interface are as close as your nearest Radio Shack Computer Center, store or participating dealer! Send me your free TRS -80 Computer Catalog. Mail To: Radio Shack, Dept. 83 -A-374 1300 One Tandy Center, Fort Worth, Texas 76102

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handheld computers Sharp

PC -1500

THE Sharp PC -1500, which uses BASIC language, is the successor to the company's PC -1211 Pocket Computer. Manufactured by the Sharp Corp. of Osaka, Japan, the PC -1500 will be distributed in the United States by the Sharp Electronics Corp. (10 Sharp Plaza, P.O. Box 588, Paramus, NJ 07652). Like the PC -1211, the PC -1500 will be available from Radio Shack (TRS -80 Model PC -2) with a slightly modified keyboard layout. The PC-1500 uses a custom 8 -bit microprocessor instead of the two 4 -bit CMOS microprocessors used in the PC1211. The new chip, which is also a CMOS device, is installed in a miniature flatpack having 76 connection pins enough to handle keyboard, display, and other I/O signals without multiplexing. Its 1.3 -MHz clock speed makes for fast, efficient program execution. Dimensions of the PC -1500 are 711/16" X 33/8" X l'/18 ", and it weighs 0.83 pounds. The unit is smaller than its more sophisticated cousin, the HHC. The PC -1500 includes 2.64K bytes of RAM and 16K bytes of ROM. The internal RAM can be expanded an additional 4K by inserting a CE -151 Memory Module in a receptacle on the back of the computer. Higher- capacity RAM and RAM /ROM modules are expected to be announced in coming months. Other features of this computer are a 26- character display, a 65 -key typewriter -like (QWERTY) keyboard, and upper- and lower -case capability. (Note that the PC -1500 will run any programs written for the PC- 1211.) You can develop your own graphics and special characters with the PC -1500 by using the GPRINT command. This permits you to treat the display as a 7 X 156 dot matrix in which any combination of individual dots can be activated. The POINT command allows you to sense dots in any of the 156 columns. The PC -1500 also provides a very versatile audio output in the form of a selfcontained programmable tone generator. The command BEEP n1, n2, n3 specifies a tone sequence having the following characteristics; n specifies the number of beeps (from 0 to 65,535); n2 specifies the tone frequency (use 0 to 255); and n3 assigns the duration of each tone (use 0 to

-

culator- style, direct execution of a wide range of mathematical expressions. Its ten -key numeric pad is particularly handy. Though functions other than , square root, pi, and the four basics ( , * and /) must be typed into the keyboard, they can also be entered into one of the six multi -purpose, user -definable, reserve keys. Normally the reserve keys, which form a row directly under the display, coincide with !, ", $k, $, % and &. Up to three functions, program lines, or even complete programs can be assigned to each key with the help of the RESERVE SELECT

-

key.

The reserve keys are made even more versatile by identifying them with labels which can be displayed by pressing RCL. Three strings of characters called templates, one for each batch of reserve key assignments, can be stored. A typical identification template for the trigonometric functions might be: TAN

SIN

COS

ATN

ASN

ACS

Each of these keys could be assigned two additional functions. While the PC -1500 has more built -in functions than the HHC, it lacks several useful BASIC commands (such as PEEK and POKE). Its edit capability is slightly less sophisticated than the HHC's and its clock mode is not nearly as versatile. Furthermore, it totally lacks the HHC's

sophisticated system of nested menus and files. The PC -1500 user must keep track of the starting address of each of the programs and always make sure line numbers within the range of existing programs are not used in new programs. Likewise, END commands at the end of each program are imperative if the computer is to avoid inadvertently executing a series of programs when only one was intended to be run. The PC- 150O's array of reserve keys helps to compensate for the lack of a file system. Up to 18 separate programs can be assigned for one- or two -key execution. A typical reserve-key assignment might be RUN 220. When the newly assigned key is pressed, the PC -1500 will run the program beginning at line 220 just as if RUN 220 had been entered. Editing PC -1500 programs with the aide of the delete, insert and cursormovement keys is simple and direct. The 46 error codes are a major asset. It's particularly helpful to clear an error code, return to program mode, and immediately see the line with the problem. Often, depending upon the nature of the error, the cursor will be blinking directly over the problem. Sharp's CE -150 Printer and Cassette Interface. Thus far only a single PC -1500 peripheral is available -the CE-150 Printer and Cassette Interface.

65,279). These capabilities can be used to create highly specialized tone combinations and even tunes. Let the results of calculations or the machine's random number function be applied to the BEEP command and the PC -1500 makes its own "music."

Using the PC -1500. Unlike the Quasar HHC, the PC -1500 is well suited for cal44

a

The HP -IL Interface Loop enables the HP -41 to be used with number of peripherals. Shown are Cassette Drive and Printer. POPULAR ELECTRONICS

The cassette interface permits the attachment of two cassette recorders, one for data and programs and the other for their recall. The CE-150 printer is by far the most sophisticated of the three reviewed here. Since this printer, which is made for Sharp by Alps, is so unusual, let's examine it in some detail. First, the CE-150 printer is not a conventional thermal or impact printer. Instead, it is a four -color, highly miniaturized pen plotter /printer. Four miniature ballpoint pens (black, blue, green and red) are installed in a revolving cylinder that slides back and forth across the paper tape. A small magnet between the black and red pens tells the computer, via a magnet- actuated switch at the left side of the carriage, which pen has been selected for printing or plotting. Pens are selected by the command COLOR n, where n is 0, I, 2, or 3 (0 = black, 1 = blue, 2 = green and 3 = red). Printing takes place when the selected pen is pressed against the paper tape by a miniature solenoid. Forward and reverse rotation of the roller causes the paper to move up and down to provide vertical inking. Back -and -forth movements of the pen holder provide horizontal inking. Diagonals are formed by simultaneous movements of the roller (paper) and pen. The plotter -like operation of the CE150 gives it amazing versatility. It can, for example, print characters in nine sizes ranging from a tiny 1.2 X 0.8 mm to a huge 10.8 X 7.2 mm ('/16" X '/32" to 7/16" X 9/32 "). The print size is selected by the command CSBZE n, where n is a digit from 1 (smallest) to 9 (largest).

When CSIZE is selected, the printing speed is an impressive eleven characters per second. The CE -150 can generate high -quality, four -color graphics with a resolution of 1

The fully expanded Quasar HHC computer system fits in an attache case and can be operated in a car, plane, or hotel room.

0.2 mm ('/64" )! Thanks to a paper -gripping mechanism, even complex graphics

requiring many movements of the paper tape are produced with a very high degree of accuracy. When the computer is placed in

COMPARISON OF HANDHELD COMPUTERS

Microprocessor Clock speed Internal RAM (bytes) Initial Fully expanded Internal ROM (bytes) Initial Fully expanded

Display Language Program files? Auto line numbering? User definable keys Internal clock? Peripheral bus Power

Quasar HHC

Sharp PC-1500

Hewlett- Packard

6502 MHz

Custom CMOS 1.3 MHz

Custom Slow

2K 4K

2.6K 7.5K

448 (HP -41C) 6.4K (HP -41CV)

16K 64K 8 x 159 dot BASIC & SNAP Yes No

16K

BASIC No No

4/62

6x3

Unknown Varíes 24 x 14- Segment RPN /HP -41 Yes (Label Names) Yes

Yes 44 -pin edge con. Rechargeable

Yes 60 -pin socket 4 X AA cells

34 X 2 Plug-in module 12 -pin edge con. 4 X N cells or

8t5/isX33/4X

7"/i6x33/ax

5.7 X 3.0 X 1.3

1

32K 7 X 156 dot

rechargeable

Dimensions (in.) Weight (ounces) *Price

13/16

11/46

20

13.2

7.4

$525

$300 (PC-1500) $280 (PC-2)

$250 (HP -41C) $325 (HP -41CV)

*Suggested retail prices. Actual prices may be lower. JULY 1982

I

command LINE (0,0)(100,100) draws a 45 °-diagonal, solid line from the leftmost pen position to a point halfway across the tape. The pen color and line format can be changed by adding two additional terms. For example, the command LINE (0,0)- (100,100),4,2, will cause the printer to orm a dashed (4), blue (2), diagonal line. The dash width can be varied from 0.4 mm (n = 1) to 1.8 mm (n = 8). Add ,B to the command and the printer /plotter will form a box or rectangle defined by the diagonal. This provides a handy way of forming borders GRAPH mode, the

around graphs, graphic characters, and data. You can even make game boards and calendar grids! Several other commands simplify the production of graphics. For example, ROTATE n, where n is a digit from 0 to 3, causes the printer to print sideways or upside down. The paper tape can be scrolled forward and backward up to about four inches by the line feed command LF ±n. Since there is no paper detector, the tape can actually be expelled from the roller by an LF command. Should this occur, the printer keeps right on printing, but on the roller instead of the tape. The set origin command, SORGN, sets as the origin for subsequent x -y pen movements the current pen position. The

handheld computers GLCURSOR command moves the pen to any specified x -y coordinate without drawing a line. There's even a TEST command that causes the printer/plotter to draw four small boxes in each of its four colors. First -time users of the PC -1500 should be forewarned that developing original graphics programs can become an entertaining, though time -consuming addiction. The printer's only shortcoming is the time it requires to print long program listings and to form complex graphics. It took me a couple of hours to develop a program that draws a stylized butterfly in four colors. Most of that time was taken by the plotter as it methodically drew various wing configurations until I was satisfied. The actual programming required comparatively little time.

Hewlett- Packard HP-41 THE HP -41 is the oldest of the handheld computers reviewed here. The only domestic handheld machine currently available, it is manufactured by Hewlett- Packard (1000 N.E. Circle Blvd., Corvalis, OR 97330). When it was first introduced a few years ago, the HP -41 was described by Hewlett -Packard as an alphanumeric, programmable, scientific calculator. But I've owned an HP -41 for nearly two years and am convinced that its programming power and versatility qualify it for designation as a handheld computer. There are two versions of the HP -41.: the HP-41C and the HP -41CV. The self-

by pressing XEQ (execute) and then typing in the program name. Programs can be keyed in by the user from his own or

published software; or factory -programmed ROM modules that plug into the ports above the display can be used. Why compare the HP -41 to newer machines like the HHC and PC -1500 when it can be operated like a calculator and doesn't have a higher-language capability like BASIC? First, though its keyboard "language" is sometimes clumsy and often more complicated than BASIC, it provides many capabilities not ordinarily found in BASIC. For example, programs are stored and called by names or labels. Line numbers are automatically inserted and, during editing, revised. Loops and subroutines can be referenced to a permanent label instead of a line number that might be hard to remember and subject to change. Also many instructions, commands, and functions can be implemented by pressing a single key. The HP -41 is also smaller and lighter than the HHC and the PC -1500. Moreover, it is supported by excellent software, a dynamic users club, and a manufacturer that interacts well with its customers and continues to introduce a growing number of versatile peripherals. HP -41 Peripherals. In the fast -moving

world of computer technology, it's not uncommon for companies to abandon older computer products as they introduce newer ones to take their place. Whether planned or unplanned, this

form of technology obsolescence is detrimental and sometimes disastrous to owners of the older systems. Hewlett- Packard has demonstrated a high degree of product loyalty by continuing to introduce software and peripherals for the HP -41. So far they have made available more than two -dozen solution books and sixteen application pacs. The application pacs include plug in ROM modules that contain programs in such diverse topics as surveying, engineering, circuit analysis, statistics, mathematics, etc. The modules are accompanied by excellent documentation and, when appropriate, a customized keyboard overlay. Numerous hardware peripherals are available for the HP -41. The 821.80A Extended Functions /Memory Module is a plug-in RAM /ROM cartridge that adds 47 new keyboard functions and 889 bytes of continuous memory. This module gives the HP -41 the ability to store programs and data in files and to access an additional 1666 bytes of continuous storage in each of one or two 82181A Extended Memory Modules. These modules give the HP -41 up to 6454 bytes of RAM storage space. The 82182A Time Module adds a quartz -controlled clock, stopwatch, and calendar capability to the HP -41. The Time Module allows the HP -41 to be programmed to execute a program, signal an alarm, actuate an external device or peripheral, or function as a versatile data logger.

contained program/data memory

(RAM) in the HP -41C can store up to 400 program lines or 63 data registers. The HP -41 CV is functionally identical to the HP -41C but has five times the RAM storage capacity (2000 program lines or 319 data registers). The memory for program lines and data registers can be allocated in any desired format by using the SIZE instruction. The RAM capacity of the HP-41C can be expanded to that of the HP -41CV by inserting a single quad RAM module into one of the four ports on the upper end of the computer. Since both computers are otherwise identical, we will simply use the designation HP -41. The HP -41 has 58 keyboard functions and a total of some 130 internal functions that can be addressed by typing in the appropriate alphabetic name. Forget a function name not on the keyboard? Just press CATALOG and every internal function will be scrolled through the 12 -character position display. Press CATALOG 2 3

to see the functions provided by plug -in ROM modules. The titles (labels) of user programs are displayed in sequence when CATALOG is pressed. Programs stored in the HP -41 are run I

46

Hewlett -Packard's bar code -reading Optical Wand (HP- 82153A) plugs into the HP-41C computer.

Programs and data can be loaded into the HP -41 via the keyboard or with the help of a handheld wand that reads bar code. The wand permits lengthy listings to be loaded quickly and error free. Barcode listings are supplied with HP -41 software. A service for converting commonly used programs into bar code is available. Programs and data may also be loaded into the HP -41 with the 82104 Magnetic Card Reader, a plug -in attachment that mounts atop the computer. A single card holds up to 224 bytes. Long programs can be stored on multiple cards. An interesting feature of this "smart" card reader is that it can be instructed to disallow alterations of on -card programs or even prevent unauthorized viewing. This provides an important degree of security for programs or data which may have required considerable development time. Fast, quiet, alphanumeric printing of program listings and data is provided by the 82143A thermal printer. The printer, which has its own rechargeable battery pack and connects to the HP -41 via a short cable, includes built -in firmware that adds 25 new printer instructions. A 44- register print buffer is included to allow combinations of alpha and numeric characters to be printed in any desired format. With patience, you can design your own graphics and special characters using the BLDSPEC (build special) instruction. There's even a built -in interactive plotting routine, PRPLOT, that prompts you for information about what to plot and then proceeds to graph the results on an x -y axis. The latest HP -41 peripheral development is the Hewlett -Packard Interface Loop (HP -IL). This is a closed -loop, two -wire link that allows an HP -41 or other compatible computer to access and control any device in a string of up to 96 series -connected peripherals. The cable length between devices can reach 100 meters. Implementing the HP -IL requires an HP -IL module that plugs into the HP -41. So far, Hewlett- Packard has introduced two HP -41 peripherals that are HP -IL compatible. The 82161A Digital Cassette Drive is a compact, mass -storage unit with a storage capacity of 131,072 bytes per tape -more than fifty times the maximum RAM capacity of the HP-

The second HP -IL peripheral is the 82162A Thermal Printer /Plotter. Functionally similar to the 82143A, the original HP -41 printer, this new printer includes several new features and an expanded buffer. The 82183A Extended I/O Module permits the new printer to print bar codes. Hewlett- Packard has also introduced the 3468A Multimeter, the first HP -IL compatible instrument designed to interface with the HP -41. Many sophisticated applications for this new multimeter are possible because its operation can be controlled by the HP -41. For example, a suitable light detector can be connected to its input to cause it to function as a solar -power meter. With the help of a Time Module, an HP -41 can sample the solar-power level at any desired time interval during the day and resume sampling the next day. The 82162A printer can then produce a plot of available solar power versus time. While some companies wait to see what Hewlett -Packard will do next, Hand Held Products (6201 Fair Valley Drive, Charlotte, NC 28211) has introduced an HP -41 add -on memory peripheral, the HHP- 16KTM. This compact unit connects to the HP -41 via a short cable

and provides a storage capacity of 4K, 8K, or 16K hvtes. Ultraviolet- erasable EPROMs are used. in the unit. HHP provides full customer service for the loading of programs into its memory unit. The introductory cost is $241, with EPROM loading available for an

additional fee. Using the HP-4 1 Die HP -41 has multiple operating males. Normally it functions as a sophisticated scientific calculator. Placed in 5hR mode, the keys execute any funciions or even complete programs prey ,s, y assigned to them by Vi- mode the keys bethe user. In come letters of she alphabet. The HP -41 that 1 own is presently configured as a specialized optical radar and communications caiculator when it is in USER mode. One f the programs I've loaded into the machine is called Range R. This program is assigned to a key .which has been given the name "R" with the help of a keyboard overlay. Range R can be executed by pressing this R key (in USER mode) or the xEQ (execute) key. In the latter instance, the display will show XEQ_ The program name is typed into the keyboard tin ALPHA mode), and the display then prompts "XMTR POWi

A

.

41 CV.

All the programs in every HP -41 software book can be stored on about 75% of a single tape! The average file access time is a reasonable 13 seconds, and the total contents of a fully expanded HP -41 can be copied from or written onto tape in under 40 seconds. Program files are easily copied from tape into the HP41's RAM by entering the name of the file and executing the command READP. JULY1982

The HP-41C shown here is generating the function sine x. The output, with the curve, is shown on the printer. 47

handheld computers ER ?" After the transmitter power is entered, a series of prompts for additional information flashes into the display. Finally, the display shows "RANGE = " followed by the range in meters. The HP -41 utilizes reverse Polish notation (RPN), a highly efficient and logical problem -solving procedure wherein numerical data are processed immediately after they have been entered into the display. This eliminates the traditional equal key found on algebraic-type calculators. Thus, the keystrokes required to add two and three (2/ + /3/ = ) becomes 2/ENTER /3/ . Developing simple programs for the HP -41 is easy, direct and fast. The program is first assigned a name or label, and the steps are then keyed in. There's no need to assign line numbers since they are automatically included by the HP-41. Editing is straightforward, though certainly not as convenient as with the HHC or PC-1500. Here's a simple timer program that decrements (counts down) in units of one from any positive number initially in the display: 01

02 03 04 05 06 07 08

LBL "TIMER" VIEW X 1

X

=0?

GTO "TIMER" BEEP END

The beeper sounds when the count reaches 1. This program is straightforward. After the number is decremented (steps 3 -4), the program compares it with 0 (step 5). If it does not equal 0, then the number is again decremented (step 6). Otherwise the beeper sounds. While this program is very obvious, it is not elegant. An experienced HP -41 user would simplify it by the apparent contradiction of adding an extra step and revising the loop instruction (GTO "TIMER "): 01 LBL "TIMER" 02 LBL 01 03 VIEW X

04 1 05 06 X = 0? 07 GTO 01 08 BEEP 09 END

This program is simpler since the HP41 need not perform a global search

through its files to find the program named "TIMER" each time it runs the loop. Instead, it searches for the local label 01 within the program. This approach is more efficient and it speeds up program execution. Therefore, a larger number must be initially entered into the display to obtain the same time delay. 48

The most important benefit of adding the extra label is the saving of four bytes: The new GTO instruction is simply GTO 01, not GTO TIMER. This short example illustrates but one of the many fine points of HP -41 programming. Complicated HP -41 programs can be difficult to develop, but the HP -41 provides a highly versatile, almost assembly -language approach that appeals to some programmers. HP -41 owners should know about PPC, an international, independent users' club for HP -41 devotees. You can receive information about PPC and a sample issue of its journal by sending a self-addressed 9" by 12" envelope with first -class postage for two ounces to PPC Calculator Journal, 2545 W. Camden Place, Santa Ana, CA 92704.

Conclusion N comparison, Quasar's HHC and Sharp's PC -1500 are both considerably faster than the HP -41. When a printed output is required, however, the HP41 can often hold its own. To simplify comparisons, I matched the PC -1500 against the slower HP -41 on a time -trial basis. For the first test, both machines were programmed to count from 0 to 1000 and sound their beeper when complete. Both computers were programmed from the keyboard in minutes with little or no editing. The PC1500 finished in a very fast 1.5 seconds versus a dismal 14 seconds for the HP -41. For a second test, both machines were programmed to print the square of each digit from 1 to 10 in identical formats (for example, '1 SQUARED IS 1', etc.). The PC -1500 program was composed in a minute or so at the keyboard. The HP41 program, however, required considerably more time. Though the bulk of the program was trivial, having everything printed on the same line was not. (I was unfamiliar with the use of the accumulator buffer in the 82143A printer and its

instruction, ACA.) Now it was Sharp's turn to eat dust. The PC -1500 needed 45 seconds to print what the HP -41 printer spewed out in 15 seconds. When the PC -1500 printed its smallest character size, it improved its speed to 23 seconds, still 50% slower than the HP-41. (Of course, the PC -1500 could have easily beaten the HP -41 if hard copy were not required.) My tests can hardly be considered worthy of benchmark status. But at the very least, they illustrate the need to carefully compare all the parameters of a handheld computer system before making judgments about which machine is faster than another. Summing Up. Now that I've had the op-

portunity to use and evaluate three of the new handheld computers, which represent five brands in the marketplace, I'm convinced they are indeed practical, priced right, and destined to thrive in the highly competitive personal computer market. But which of the handheld computers examined here is best? Since each of the machines has special characteristics, there is no clear answer. Here are some capsule comments about each model's attributes to help you determine which one best fits your applications and requirements. The Quasar HHC (or Panasonic equivalent) is well- suited for file- structured programming. It has several very useful peripherals and can interface with color TV receivers and video monitors, as well as other computers, via its optional modem. Of the three machines reviewed here, the HHC most closely resembles what one might expect if a desktop personal computer were reduced to a

handheld format. The Sharp PC -1500 (or Radio Shack equivalent) has a drawback in its lack of a file system, but it has more mathematic and logic functions than the HHC. Though it lacks the HHC's wide range of peripherals, its optional printer /plotter is by far the most impressive and versatile of the three we looked at. Furthermore, its color print provisions give one an added benefit. The Hewlett- Packard HP -41 has neither the programming ease of BASIC, nor a keyboard that is familiar to typists. It has many single -key functions that speed up program entry, however. Nearly all of its keys are redefinable, and its keyboard "language" generates its own line numbers and automatically files programs by alphanumeric labels. Numerous peripherals are widely available for the HP -41, though given time, the others, which are recent entries on the market, could well catch up. With the HP -41, one cannot interface with other general -purpose computers or use a common high level language. The HHC and PC -1500 are further set apart from the HP -41 by their somewhat larger size, which allows for more display characters and a standard keyboard layout. However, the HP -41 is easier to hold in one hand, and its keyboard is simpler to customize. If you are interested in acquiring a handheld computer, your purchase decision also will be influenced by price and availability of peripherals. You should arrange for a firsthand demonstration and inspection of each machine, of course, and determine which meets your needs best. No matter which you select, you will be impressed by any one of O them. POPULAR

ELECTRONICS

SINGLE -ENDED noise reduction may be all you need to strip background noise from on- location voice recordings, dub "clean" home -movie soundtracks, mute public-address microphones, and improve the audio from video tape recorders. The simple audio gate described here can handle any of these tasks. No encoding is required of the signal source, and with a little practice you should find the gate quite satisfactory for most nonprofessional applications. An investment of less than $30 can buy you a cost -effective alternative to the more sophisticated noise- reduction devices currently available. Audio gates have been used by professionals for many years- recording studio engineers often refer to them as "noise gates." An audio gate does not constrict and expand the bandwidth of the reproducing system. Instead, it is simply a voltage -controlled attenuator with two states. When a normal signal level is present, the gate operates at unity gain. Below this level, the gain automatically drops, quieting background noises -and the residual signal. This action is comparable to dynamic range expansion, except that the gain reduction is fixed and occurs at a definite, preset threshold.

Circuit Description. In the circuit

SVRLT

AUDIO GATE PXRAN DS

DYNAV IC

RA\C

Obtain effective noise reduction with this under -$30 circuit BY JOHN H. DAVIS

(Fig. 1), input ICIA can be operated as a buffer or a gain stage, depending on input level. Its output is coupled through CI to the voltage-controlled attenuator (R3. R4, QI) and the input of a level comparator (ICJC). The level comparator is biased with a threshold voltage from RIO. As long as no signal peaks exceed this threshold voltage, the output of IC1C will be positive and no charge will be applied to C3. This means the channel resistance of QI will be low, allowing voltage divider R3 -R4 to attenuate the signal applied to the output buffer (ICIB). When positive signal peaks rise above the threshold, the output of ICI C will switch negative for a fraction of each cycle, charging C3 through DI. Now the channel resistance of QI rises to several times that of R3, effectively disabling the R3 -R4 voltage divider. Attenuation is thus removed from the audio path. With the component values given, the threshold may be adjusted to begin anywhere from 160 mV rms to less than

JULY 1982

49

audio gate 10 mV rms. (The maximum possible threshold decreases to about 130 mV rms with 9 -V battery operation.) The object, of course, is to find a threshold level that is below the important audio information but above the noise. As shown in Fig. 1, the audio gate works well for audio input levels from 300 mV to 2 V. Lower input levels should be brought within this range by amplification; higher input levels produce a minor increase in distortion prior to the onset of clipping (8 V rms; 5 V rms for battery operation). However, if high audio levels are accompanied by significant noise, attenuation should be employed to ensure adequate threshold control. The gating time constants have been

chosen so that attack and decay rates are compatible with most speech and music. Of course, these can be varied as special needs dictate.

Construction and Operation. Assembly is straightforward, especially if a pc board is used (Fig.2). The audio path is not overly critical, but the comparator section changes state rapidly, so a short path from the IC to ground through C4 and C5 is important. Be sure to observe capacitor polarities. Shield cable is recommended for input and output connections. After assembly, double check all wiring and component orientations. Before putting ICI in its socket, apply power and check that the potential at points E

JUMPER

F is less than 18 V and of correct polarity. Now remove power, discharge all the capacitors, and insert ICI in its socket. Connect the audio gate between a signal source and an amplifier, and reapply power. (If other noise -reduction and

AUDIO GATE PERFORMANCE SPECIFICATIONS Input impedance: 100 kit Output load: 2.5 kit or greater Frequency response: 20 Hz to 20 kHz,

+0, -1 dB Distortion: 0.05% for operation between threshold and 2 V; generally less than 0.25% at other levels, depending on FET (QI) characteristics Recommended line level: 300 mV to 2 V rms

Maximum output: about 8 V rms (5 V rms for battery operation)

equipment is used, it should precede the

audio gate.) With an audio signal present, practice adjusting threshold control RIO. You should hear the gain change when the audio input exceeds the threshold level, and LED1 should light simultaneously. If R10 is set too low, the noise may not be attenuated; if R10 is set too high, the audio level may fluctuate erratically. +ISV

L

Iy

SOURCE

II7V C INPUT

i

-15V SOURCE

Fig.

1.

Schematic of the audio gate circuit, including power supply.

PARTS LIST

-Full -wave

B1

bridge rectifier module,

-A, 100 -V or more C1- 0.47 -µF, 100 -V Mylar capacitor C2- 4.7 -µF, 16 -V electrolytic C3- 2.2 -p.F, 35 -V tantalum or low -leak1

-15

R3 kit R4 -see table R5 Mil

-1

R6-680 ft R7 -39 kit

age electrolytic C4,C5 -µF, 35 -V electrolytic C6,C7- 1000-p,F, 25 -V radial -lead

R8 -2.2 kit, 1/2 W R9* -330 kit R10 * -kit linear -taper potentiometer

electrolytic C8* #,C9* 1000-µF, 25 -V electrolytic C10 2.2 -µF, 50 -V nonpolarized electrolytic D1-1N914 diode IC1- TL074CN quad Bi -FET op amp J1,J2- RCA -type phono jacks LED1 -Red light- emitting diode The following resistors are all 1/4-W, 5% unless otherwise noted:

R11 *

-1

#-

#-

R1

-100 kit

R2 -33

kfl

-5

-180B

R12#,R13#-47 kit R15# -100 kit R16 # -50 -kit audio taper potentiometer

Q1- 2N3819 or GEFETI transistor T1 -24 -V center tap, 100 -mA secondary Denotes component not required in duplicate for stereo version # Denotes component required for optional features as described in text

*

Applications. The audio gate was designed for flexibility. Consequently, certain adaptations must be made for specific applications. For example, the optimum amount of gate attenuation depends on the relative noise content of the incoming signal and how objectionable an abrupt level change would be. As little as 3 to 6 dB of gating will help in the transfer of old phonograph records to tape or make voices recorded in noisy locations stand out from the background din, enhancing intelligibility. Film soundtrack recording used such methods until the advent of extensive studio re- recording ( "looping "). However, it is still common in television, where production budgets are tighter. The preferred amount of gating in home -music systems ranges from 12 dB for background music down to around 6 dB for more critical listening. On the other hand, 20 dB is not excessive when muting a public- address microphone if the exact threshold is adjusted carefully. The table gives values for R4 to produce five different gate attenuations between 3 and 20 dB.

POPULAR ELECTRONICS

Value of R4 Audio Gate Attenuation 33 101 3 dB 15 kfl 6 dB 8.2 k!2 9 dB 4.7 k11 12dB

20dB

1.5 kdl

JUMPER FOR

If gain is needed to bring audio levels up to the specified input range, two modifications to the audio gate's first stage are recommended. Improved signal -to-noise ratio is obtained when the rectifier is moved off the circuit board and additional filtering is added (Fig. 3). The first stage is then set up to provide a voltage gain of 10 (Fig. 4). Increasing R 15 will raise the gain further, but exceeding about 470 kilohms will introduce noise and instability. If input gain is not needed, a wire jumper must be used in place of R15. The audio gate can be useful in electronic music experiments where a number of audio signals are being mixed together. For example, nearly all syn-

641N OI

-R2-

s

thesizers produce some vaguely

TO

-R3-

J2

musical "noise" at full gain. This is feedthrough from the internal voltagecontrolled attenuators. A bank of synthesizers working together -or any other group of sound generators combined in parallel-would exhibit a lower residual output if each input was first

D

RI

r

R

15/14

e

ICI

10

(

R12

a7n A

LEDI K

I

I

RII

C2

t

1

RI

C5

+

I$

-R6-

C7 BI

I+ (

R7 C3 1

117

C9

F IOOOyT

INPUT

R13

47lL

WMAM

(OFF BOARD)': (ON

a

0+15V

T

1

Fig. 2. Use the foil pattern at top to make printed circuit board and install components as shown.

iT

0-15V

BOARD

S/N can be improved by using extra filtering as shown here.

Fig. 3. The

View of the

internal arrangement of the author's prototype.

JULY 1982

51

Now NRI takes you inside the new TRS -80 Model III

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1$

221

FOP T,.24 FOk Ir/6

t13,9Cirt,t5r:5Elil.2l>;MExT

SO

TO

26:Ti24,1:5ET:21.1):kETI1I)Ir K2O S IS It.

41 IkIN'861."YM4t !4

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Ok M:t

OR 11c1 41 .N111MitN.'11).N=M-10.NT OR M;5á !lIM111."":0010 'I /

44

Mt=IM',Mr11):1011-fIr02 FOR I=63 TO

4IVkIMTI1..'

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'N I.Mt:1a3/:665Uk 510/ ïti O=N:1+46:605UI 17/ 131

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WA

52

241

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You Explore the New TRS -80 Model III

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high -speed cassette loading, built -in interface for parallel printer, and provisions for optional disk drive. Its 4K RAM is internally expandable to 16K or 48K and its BASIC language is compatible with most Model I software. Along with your multimeter and the NRI Discovery Lab, this latest concept in advanced microcomputers is yours to learn with, yours to keep and use for your own personal programs, business use, and other applications.

Get all the details on this exciting course in NRI's free, 100 -page catalog. It shows all equipment, lesson outlines, nd facts on other electronics courses such as Complete Communications with CB, TV and Audio Servicing, Digital Electronics, eleven different interest areas in all. Send today, no salesman will ever bother you. Keep up with the latest technology as you learn on the world's most popular computer. If postcard has

You also work with a precision

26- scale, 6- function LCD Beckman multimeter featuring full portability and a

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been used, write to NRI Schools, 3939 Wisconsin Ave., Washington, D.C. 20016.

Advanced Technology

Microcomputer Is Yours to Keep As part

of your training,

Sc-Hill ho ols Continuing Education Center

DIRNRI

t

i

McGraw '

3939 Wisconsin Ave.

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NRI sends you the new, state -

of- the -art TRS-80 Model III microcomputer. This functional unit is complete with 65 -key keyboard and 12" display in-one desk-top unit. It features

(IRS-80

JULY 1982

is a

trademark of the Radio Shack division of Tandy Corp.)

55

$ 299

28K Commodore VIC Personal Computer (60% more powerful than VIC -20)

Ris

R14

CIO

2.2µF

IIK

100K

JI CI

.475F RI ZOCK

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Fig. 4. First stage with gain of 10.

fed through an audio gate. An alternate application involves modifying the gate's attack and decay rates. Figure 5 shows R6 and R 7 as potentiometers, permitting the audio gate's attack and decay times to be continuously adjustable. Note that the minimum value of R7 must not be less than R6 to ensure full gating. Portable operation is possible with two 9 -V batteries (Fig. 6). Since gate adjustment is largely done by ear, LEDI can be eliminated in the interest of power conservation.

.

15 DAY FREE TRIAL. Return within 15 days complete and undamaged for refund of purchase price.

DON'T MISS THIS FANTASTIC SALE!!

Phone 312-382-5244 to order and get delivery in 2 to 7 days, or send a certified check, money order or personal check to: PROTECTO ENTERPRIZES, BOX 550 BARRINGTON, ILL. 60010. WE HONOR VISA AND MASTER CHARGE, ship COD. Add 10.00 for shipping, handling, insurance. Illinois residents add 6% tax.

Stereo Operation. Since many applications for the audio gate involve monophonic signals, this unit was de-

i

CIRCLE NO. 46 ON FREE INFORMATION CARD

signed accordingly. However, for stereo operation it is only necessary to build a second pc board, duplicating all

_

DI

R6 10K

25OK ADJUST DECAY

ADJUST ATTACK Cb

I0K

2.25F

Mt Intosh

Fig. 5. Using pots for R6 and R7.

STEREO CATALOG and FM DIRECTORY

the components of Fig. I except those marked with an asterisk in the parts list. Then tie the boards together electrically with jumper connections between five key points on the two boards (B, D, E, F, and G). That is, wire left -

Get all the newest and latest information on the new

McIntosh stereo equipment in the McIntosh catalog. In addition you will receive an FM station directory that covers all of North America.

channel point B to right -channel point B, D to D, etc. +9V SOURCE

.9V

VIM IMP 0 0 0 C1

I

r McIntosh Laboratory, Inc.

o

_r_9V

PE

SEND TODAY!

7

10005F

(DPDT)

C?

I

1000

J_

9V SOURCE

Fig..6. Power supply for portability.

Binghamton, N.Y. 13904 -0096 NAME ADDRESS STATE_

C6

+

C1

East Side Staion P.O. Box 96

T +

ZIP

LCITY

J

Both gates will open when either (both) stereo channel(s) is (are) active, and neither gate will attenuate until both channels are inactive. This simultaneous action prevents unwanted ste0 reo -image shift at low -input levels.

If you are in a hurry for your catalog please send the coupon to McIntosh. For non rush service send the Reader Service Card to the magazine. POPULAR ELECTRONICS CIRCLE NO. 29 ON FREE INFORMATION CARD

4-TRACE CONVERTER OR OSO LLOSCORS Make your single -trace instrument more useful with this low-cost circuit BY JIM MORGAN HAVE you ever found yourself staring at the nonworking "innards" of a stereo audio amplifier or a complex digital circuit, wishing you

had

a

multi -channel oscilloscope?

Now, for about $70, you can build an oscilloscope switch that can display 2, 3, or 4 channels of inputs on a single trace scope. Bandwidth at the 3 -dB point is about 4.5 MHz, but the scope switch is usable with signals up to about 20 MHz. Isolation between switches approaches 65 dB, and the input impedance is 98 kilohms (which can be improved if desired). On ac, the switcher will accept signals to 15 V peak -to -peak, while on dc, signals can be ±7.5 V. The display can be chopped at adjustable frequencies from 12 to 210 kHz, and a fixed 200 -Hz rate is also available. A built -in trigger processor provides a choice of input channel to do the oscilloscope triggering. Power requirement is ±9 V from alkaline cells or a simple line- operated power supply. The switcher can also be used as the staircase generator for a transistor curve tracer, or it can produce four outputs from a single source so that a single audio preamplifier can drive four power amplifiers. A single video source can also be used to drive four video monitors. The complete schematic is shown in Fig. I.

Circuit Operation. The central element of the oscilloscope switcher is ICl, a CMOS quad analog switch. This chip contains four independent spst switches (electronic), each controlled by its own flip -flop. When a CMOS switch is "open," its impedance approaches 2000 megohms, which provides ample isolation between the input and output. In the closed condition the series resistance is approximately 80 ohms, and the attenuation of conducted signals is insignificant. Since the switcher's four input chan-

JULY 1982

57

4 -trace converter nels are similar, we will discuss only channel A. The desired input signal,

applied

to

Jl,

coupled

is

to

DC /LO /HI /REF selector switch Sl. the DC position, the input signal is

In directly coupled to ICI, while in the Lo or HI positions, the signal is ac- coupled through either Cl for low frequencies or C2 for high frequencies. In the REF position, the switch is fed a dc voltage determined by the setting of POSITION control R5 to allow for trace positioning. The signal at J1 is also coupled to the trigger -processing circuit to synchronize the scope to the selected signal. The POSITION control (R5) is con-

nected across the positive and negative

I

voltage sources so that each trace can be positioned as desired on the scope CRT display. Capacitor C3 bypasses the input signal away from the POSITION control and effectively places the lower end of the ATTENUATION potentiometer at ground level. The POSITION control applies a selected dc bias to the

justed via STABILITY control RIO to generate pulses whose frequency ranges from 12 to 210 kHz. When 55 is in the ALTERNATE (closed) position, the large value of C13 is placed in the timing circuit, reducing the IC2 output frequency to approximately 200 Hz. The CHOP mode of S5 is used when observing low-frequency signals, while the ALTERNATE mode is used for ob-

switch input to determine trace position. The four switch outputs (pins 2, 3, 9, and 10 of ICI) are connected in parallel and feed the SCOPE VERTICAL INPUT (J5). When CHOP- ALTERNATE switch S5 (fitted to STABILITY potentiometer R10) is in the CHOP (open) position, astable multivibrator 1C2 can be ad-

serving high frequencies. STABILITY control R10 can be adjusted to remove any flicker or display breakup when the input frequency is similar to the 1C2 pulse frequency or one of its harmonics. The output of IC2 drives decade counter IC3, whose outputs, in turn, drive the four flip -flops within ICI.

AC-LO

A

AC-HI

2

,.IAF TO SB

J21

C4

MINIMUM

ICI 4066

SI

IOOK REFERENCE' ATTENUATION

9 R5

O

10

l

50K POSITION

+7.5VO

2

I

R

-7.5V

13

TO S8

L

6

3

SCOPE

VERTICAL INPUT

4

R6 J3 CL

T

IC3

DISPLAY

4017

561

CHOP

ALTERNATE

CLK ENABLE

CI3

131

C14

IyF

O

J5

SCOPE

EXTERNALJ TRIGGER

2- CHANNELS

3- CHANNELS

t4- CHANNELS

4

+7.5V 8I

120pF

RIO

D

47011

-7.5V

QI

B-

A R12 TO

7.5V

S8

2N3906

C19

.OIAF R14

D

R8

-

IOOK

s s8

TRIGGER

SELECT IM

-7.5V

+7.5V 6811

Fig.

1.

The heart of the scope switcher is a CMOS quad analog switch.

PARTS LIST B1,B2 -Six 1.5 -V alkaline cells

C1,C4,C7,C10- 10 -SF, 30 -V nonpolarized capacitor

C2,C5,C8,C11,C18-0.1

-1.1,F,

50 -V Mylar

capacitor C3,C6,C9,C12,C13-1 -p,F, 30 -V tantalum capacitor C14,C21- 120 -pF, 50-V disc capacitor C15,C19,C20- 0.01 -p,F, 50 -V Mylar capacitor C16,C17- 470 -p F, 16 -V electrolytic IC1 -4066 quad switch IC2 -555 timer IC3 -4017 decade counter J1 through J6-BNC connector, UG1094

58

Q1- 2N3906 pnp transistor Q2- 2N2222 npn transistor The following are 1/4 -W, 10% resistors unless otherwise noted: R 1,R2,R3,R4- 100 -k12 linear -taper potentiometer R5,R6,R7,R8- 50 -k12 linear -taper

potentiometer R9, R11 -1 kit R 10- 100 -k12, audio -taper potentiometer with attached switch (S4) R 12, R 13

-68f2

R14 -100 kit R15 -1 Mn R16 -47 kit

R17-470 k1t R18-4.7 k12 R19-470 it S1

,S2,S3,S4,S8-4-position rotary switch

S5 -Spst switch (part of R10)

S6-3- position rotary switch S7 -Dpdt slide switch Misc.- Suitable case (61/2" X 6"

X 3 ", Sprague QEP- 1715 -01 or similar), hookup wire, battery holders, knobs, press on type, mounting hardware, etc. Note: The following is available from Hi- Technology Designs, Box 457, Fairview, OR 97024: etched and drilled pc board for $6.95.

POPULAR ELECTRONICS

DI-04 IN4001

Fig. 2. Optional

ac-powered dc supply can be used instead of batteries.

RI

Construction. The project can be as-

39011

sI

sembled using point -to -point wiring or the pc board shown in Fig. 3. Component installation is shown in Fig. 4. The circled letters in Fig. 1 and Fig. 2 refer to pads on the pc board. Note that some resistors are mounted on end to conserve board space. Note also that input capacitors Cl, C4, C7, and C/O are nonpolarized types, while the STABILITY control has an associated switch (S5) that closes when this control is at its extreme counterclockwise positions If you take care with lead dress, frequencies up to and beyond 4.5 MHz can

D5

IN4739 9.1V 117

V

AC

ï

D6

IN4739

9.IV

R2

390L

PARTS LIST (Power Supply)

C1- 1000 -p,F, 50 -V electrolytic

S1

-Spst switch

T1- 12.6 -V,

through D4-1N4001 D5,D6-1 N4739, 9.1 -V zener R1,R2-390 -SZ, 1/4 -W resistor

1.2-A transformer (Radio Shack 273-1505 or similar) Misc.-Line cord, hook -up wire, tie lugs, etc.

D1

connected to the reset input of IC3 and enables selection of three of the 1C3 outputs to allow the display of two, three, or four traces on the scope display. The use of the decade counter ensures that only one flip -flop within ¡Cl is enabled at a time. TRIGGER SELECT switch S8 selects one of the inputs from JI through J4 and applies the selected signal to the trigger processor formed by Ql, Q2, and their associated components. Essentially, the two-transistor circuit forms a high -gain amplifier /shaper whose output is coupled via J6 to the scope's external trigger input. The two transistor circuit will operate with inputs as low as 10 -mV rms. Since the current requirement is less than 20 mA, a pair of 9 -V batteries can be used for the power supply. If BI and B2 are formed from six 1.5 -V alkaline cells in series, up to 80 hours of intermittent duty can be expected. An optional ac- powered dc supply is shown in Fig. 2. DISPLAY switch S6 is

Internal view of the author's prototype.

be displayed. Use BNC connectors for the inputs, and 20 -gauge wire to make

56-2

1 RI5

R14

ICI

Cÿ Rÿ

()se

S6

J2

3O9

GND 10

+Vae O7 S6-I P-6

Vse

O5 S5

T

IC3

-C21-

-CRI7

C

R161 IS

RI

02

13

(JS6

-670

J4

C20

CI6

CIS

CI`

/

-G RII

IC2

n

-CI4-

s iL J5

RIO

RIO

S5

® Fig. 3. Exact -size foil pattern.

JULY 1982

Fig. 4. Component placement diagram.

the necessary switch /control -to -board connections. The board is then installed within a suitable enclosure whose front panel can accommodate the various controls and the input and output connectors. Each should be suitably identified as to use. Many components can be directly mounted on the switches and potentiometers. Either the battery pack or the line-powered dc supply can be located within the enclosure. If the supply circuit is used, its power cord can exit via a grommetted hole at the rear of the enclosure. Install fresh alkaline cells if battery operation is desired.

Checkout. Turn on power to the switcher (SI in the ac supply or S7 in the battery version) and measure +7.5 V between pins 14 ( +) and 10 (GND), 59

4 -trace converter and

- 7.5 V between pads

-)

15 ( and Also check that the correct dc input voltage appears at the pertinent pads of the three ICs. Connect a scope between pin 3 of IC2 and ground. A series of pulses should be displayed. Now, by starting at the maximum clockwise position of STABILITY control R10, and rotating this control counterclockwise, the displayed pulse frequency should increase. When the associated switch (S5) closes, the pulse frequency should drop to about 200 Hz. You may have to reverse the connections to R10 to get the desired result. Set the scope vertical attenuator to 1 V/division, dc input, and position the trace on the center graticule line. On the switcher, set all the POSITION controls fully counterclockwise, DISPLAY (S6) switch to 4 CHANNELS, and the ATTENUATION controls to maximum. Connect the scope vertical input to

10 (GND).

connector J5. Now, with the scope on internal trigger, a straight -line image should appear near the bottom of the screen. Adjust the four POSITION controls on the scope switcher to create a staircase of convenient size with channel A on the botSCOPE VERTICAL INPUT

CHANNELS, and the scope traces are

tom, channel B above it, then channel C, and finally channel D on the top. Adjust the scope's vertical attenuator and position controls to center the display. Each step of the staircase should be about a 2 -V increment. Connect the switcher's SCOPE EXTERNAL TRIGGER jack (J6) to the scope's external trigger input and set the scope trigger controls accordingly. Using a signal generator, apply analog or digital signals to the four input connectors and note that they appear on the four traces. Use the TRIGGER SELECT switch (S8) to select the desired trigger signal and adjust the scope trigger controls for a stable CRT display. You can now adjust the ATTENUATION and POSITION controls on the switcher to position the image as desired.

centered, the frequency present at SCOPE VERTICAL INPUT connector J5 will be lowered by one -third and one half, respectively. The staircase output can be used as a driver for a transistor curve tracer. Since ICI is bilateral, a signal can be applied to J5 and then distributed to four different circuits connected to Jl through J4. This setup wil also work with digital signals -you can drive four displays from one computer (or video game). Some design tradeoffs were made to keep the cost down. For example, the ATTENUATION controls are low -cost 100 -kilohm units, which in conjunction with the scope input impedance, produces a 98- kilohm input impedance for the switcher. The input attenuators (RI -R4) may be increased to 1 -megohm units, but circuit response time will increase because it will take longer to change the input capacitors. This approach could be used when monitoring high- impedance circuits. However, a high input impedance will cause some rolloff on the edges of observed pulses if the ATTENUATION controls are in other 0 than their MINIMUM positions.

Other Applications. Besides its application as a four -trace add -on for oscilloscopes, the switcher can also be used as a variable- frequency square -wave generator with a maximum peak-topeak output of 15 V. To implement this operation, set the input selector switches (S1 to S4) to REFERENCE and the DISPLAY switch (S6) to 2 CHANNELS. If the DISPLAY switch is now set to 3 or 4

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POPULAR ELECTRONICS

PROGRAMMING EPROM's WITH A SVA1 COV.D,T7 Hardware -software system interfaces with compute,- for easy, sophisticated programming from keyboard, cassette or disk

BY JOHN DOOLITTLE

AND SLOBODAN TKALCEVI:.

_

Part

EPROM PROGRAMMIER

WHY pass up advanced digital construction projects because they involve EPROM (Erasable Programmable Read Osly Memcry) pro gramming? Ifa small compute- su.h as the TRS-80 is available, then the EPROM programmer descrited hem can expand your digital design .n'ork inexpensively. This modest -cost peripheral device can program EPROMs with data loaded from a keyboard, cassette, or diskette. Its other operating m3des verify programmed EPROMs against the programming buffer, list the EPROM or programming buffer :ontents to the monitor screen, c)py the contents of one EPROM to LEnother and check that an EPROM is comp:etely erased before re-programming. EPROMs are most commonly used for storing machine -language pr grsms to control microprocessors or fir storing look -up tables where a large number of inputs and ou -puts are needed (for example, converting one binary

eprom code to another, defining mathematical functions, or controlling sequential circuits). Usually, microprocessor control programs that are to be stored in EPROM are written in assembly language and then converted into machine- compatible binary code. While this can be done by manually resolving the necessary op -codes and addresses, a more efficient approach is to use a small computer that supports a text editor and assembler. Once the assembly language text is entered and assembled into binary code, it can then be written directly to EPROM using the peripheral programmer. An EPROM programmer interfaced with a computer benefits from system software support (such as an editor or assembler), and can use the logic and computational resources of the computer to control its operation. By making address generation and programming -pulse sequencing into software tasks, the hardware component count can be reduced to a bare minimum. This EPROM programmer can program 2704-, 2708 -, 2758 -, 2716 -, 2732 -, and 2532 -type EPROMs, giving the user a selection of 1/2K, 1K, 2K, or 4K by 8 -bit devices. The design includes five power supplies to provide the voltages necessary to program all these memory chips. While the printed circuit directly interfaces with the TRS -80 Model I expansion bus using a 40 -conductor ribbon cable, its design can be easily adapted for any computer that allows access to the CPU data and address lines.

Working with EPROMs. There are basically only two operating modes for EPROMS: Read and Program. Most EPROMs are byte -addressable, which means that 8 bits of memory contents can be accessed by specifying a unique byte address. The data lines remain electrically disconnected, or "three stated." until the chip is enabled. This allows several memories or I/O devices to share the same data bus in turn. Once enabled by supplying a chip select signal, data may be read from the device simply by providing the desired address. Valid data becomes available on the output lines a short time after the address is specified. This brief delay, or "access time,' allows the address lines to settle to constant values. Before programming, all bit locations of an EPROM are in the one state as a result of exposure to ultraviolet light. Data is placed in the device by entering zeros at the required bit locations of any byte addressed. The Program mode is activated by supplying a write enable signal and a programming pulse

62

I

2704 /2K EPROM 24

A7 A6

23

2

22

AS

21

A4 A3 A2

AI

5

20

6

19

7

18 17

AO

6

00 OI

15

o

14

02 GND

2706 1K

13

2

AO-All: 00 -07:

2716 2K EPROM

EPROM

vcC

A8 GND

Vpp

VBB

CS/WE

OE

VDD

A10

PROG.

CE

07 06 05

04 03

ADDRESSES DATA OUTPUTS

CHIP ENABLE Vpp: PROGRAMMING VOLTAGE

CHIP SELECT WE: WRITE ENABLE CS

CE

:

OE: OUTPUT ENABLE

2758 I

EPROM

2732

2532

2K EPROM

4K EPROM

'k 21

VPP

20 0E 19

GND

21

AII



0E

9

2i

20 9

Alo

18

CE

VPP

0E/ PROG.

A10

B

"LI- Al

CE

PROGRAM

EPROM PiN

21

-5 25.5 All 25.5

1. Pin designations and programming signals for the EPROM chips that are programmable with this project.

Fig.

to the appropriate pins. The duration and amplitude of the programming pulse must be within specified limits. Some EPROMs (2758, 2716, 2732, and 2532) can be programmed in one pass because a relatively long pulse is supplied for each byte addressed. Other types (2704 and 2708) demand that a short programming pulse be repeated many times with a delay inserted between pulses. (This allows for adequate

heat dissipation.) Whatever the

EPROM type, it is normal to make many passes through the entire memory until each affected bit location has been pulsed for a total time exceeding a specified minimum.

Verification after programming is done by reading back the contents of all programmed bit locations and comparing them with the original data. If modifications to the EPROM data are deemed necessary, and involve changing a 1 to a 0, they are easily made by reprogramming with the altered data. Of course, corrections that involve changing a 0 to a 1 can only be made by first erasing the EPROM. All of the EPROMs considered here are 24 -pin DIP packages which have identical pin configurations except for the assignment of pins 18 through 21. The pin designations and programming signals for all chips programmable with POPULAR ELECTRONICS

routing the affected signals through "personality" modules wired specifically for each EPROM type.

TABLE I -PORT ADDRESSES 8255 Port

CPU I/O Port Address

A B C

F8H F9H FAH

Control

FB H

Circuit Operation. The schematic diagram of the EPROM programmer appears in Figs. 2 and 3. Computer interfacing is greatly simplified by designing the circuit around a general- purpose programmable I/O device such as the Intel 8255A Programmable Peripheral Interface (PPI), shown logically in Fig. 4. This chip communicates with the CPU through the eight lines of the data bus and provides for 24 I/O lines that can be connected to the computer data bus under program control.

the EPROM programmer are shown in Fig. 1. The similarity in pinouts means that a general circuit can be designed to accommodate the various types with only four lines being unique to each EPROM. The connection of these four lines can be made most conveniently by TRS -80 INTERFACE 4

DO

PC2

DO

PC3

DI PBO

02

P81

PB2

03

P83

04

05

29

P84 PB5

05

PB6 PB7

D6

PAO

07

6 7

B 8

9

9

10

PA2

13

22

14

23

15

24

16

25

PA4 PA S

RC

ICI

3255

PA6 PA7

WR

PCO PC

1

PC7

20

02

21

21

03 D4

05 06 D

4

8 7

6

2

5

0

4

39

3

38

AO

AI

A2

EPROM SOCKET S01

A3 A4 5 A6

37

TO FIG.

A7

4

23

5

22

NC

A8 A9

10

GND

vCC

12

24

4

8

+5V 8 PC 6

12

IC4

IC6 75451

12

13

R7

+5v

2.2K

+5V PC4

IC4 74LS32 2

R3

PC5

5.6K

13

12

IC5 75451

I

ONO

C4

22 ;IF

+

R2 10K

RESET

F

I

PA3

AI

19

D1

20

PA I O

18

00

+ 5V

3

PARTS LIST

Cl,C2- 1000 -µF, 16 -V electrolytic C3-1000 -µF, 50 -V electrolytic C4-22 -1.1,F, 15 -V electrolytic C5,C6,C8-0.1

-1.1.F, 20 -V disc ceramic C7-0.1 -, F, 50 -V disc ceramic D1 through D6 N4004 diode

-1

Fl -0.5-A fuse and holder IC1 -8255 programmable peripheral interface

IC2- 74LS30 8 -input NAND gate IC3- 74LS32 quad 2 -input OR gate IC4- 74LSO4 hex inverter

IC5,IC6-75451 dual peripheral AND driver IC7,IC8 -723 precision voltage regulator IC9- LM320 -5 negative 5 -V regulator IC10- LM340-5 positive 5 -V regulator IC11- LM340-12 positive 12-V regulator K1 -24 -V, 700 -ohm 4pdt relay (PotterBrumfield R10- E1- W4 -V700, with socket 27E213, or similar) LED1 -Green light- emitting diode LED2,LED3 -Red light- emitting diode The following are 1/4 -W, 5% resistors unless otherwise noted: R1,R4,R6,R7,R10,R17 -2200 ohms R2,R11- 10,000 ohms R3 -5600 ohms R5,R9 -10 -ohm, 1/2 -W R8,R 12- 10,000-ohm potentiometer R13 -220 ohms R14,R15,R16 -330 ohms S1 -Spst switch 501 -24 -pin, zero -insertion -force socket (Textool 224 -3344 or similar) T1 -10 -20 CT -40 CT, 300 -mA transformer (Triad F -91X) Misc. -Four 16 -pin DIP header sockets with covers, suitable enclosure, 40- conductor ribbon cable with connectors, line cord, mounting hardware, etc.

Note: The following are available from Parhelion Inc., Box 3602, Stanford, CA 95405: complete kit including drilled and etched pc board, enclosure, and driver program listing for $134.95, plus $5 for postage and handling. Also available separately are an etched and drilled pc board for $21.95, plus $2 for postage and handling; driver program listing for $10.95; driver program on cassette for $19.95, plus $1 for postage and handling; driver program on diskette for $21.95, plus $1 for postage and handling. California residents, please add 61/2% sales tax.

Fig. 2. Interfacing to the computer is provided by a general- purpose programmable I/O device, the 8255A.

JULY1982

63

+12V

-5V +5v

+25.5V-w41-1 3

A

AIO

5

R15

R14

33011

33011

LED 2 PRGM (RED)

READ

LED

I

(GRN)

4-5V

All

+12V 6

PERSONALITY MODULE SOCKET

1 +5V

IT

=

-0-}-1

LED 3 POWER

F

R16

33011

+5v

G

FROM FIG. 2

H

Fig. 3. Precision voltage regulators IC8 and IC9 are used to supply 5- and 25.5 -V programming pulses.

TABLE Control byte 00 01

02 03 04 05 06 07 08 09 OA OB OC OD OE OF

80 82

64

II- CONTROL BYTE FUNCTIONS 8255 response

reset PC0 PC0 set reset PC1 PC1 set reset PC2 PC2 set reset PC3 PC3 set reset PC4 set PC4 reset PC5 set PC5 reset PC6 PC6 set reset PC7 PC7 set all 8255 ports in output mode 8255 ports A &C output, B input

Function reset EPROM add. A8 set EPROM add. A8 reset EPROM add. A9 set EPROM add. A9 reset EPROM add. A10 set EPROM add. Al0 reset EPROM add. All set EPROM add. A11 turn off 25.5V turn on 25.5V turn off 5V turn on 5V relay PROGRAM mode relay READ mode not used not used PROGRAM mode

READ mode

In this application, the 8255A's I/O lines are organized into two eight -bit ports (A and B) and a special port (C) with eight lines that can be set or reset independently- without disturbing the other bits of the port. The lower half of port C is used in conjunction with port A to supply up to 12 bits of address information to the EPROM from the CPU data bus. The upper half of port C controls relay K1 and the switchable power supplies during the programming sequence. Port B is used for data transfer between the EPROM and the CPU. An additional 8225A port (Control) receives a control byte which configures separately ports A, B, and C for input or output as required. The 8255A remains in a specified configuration until a new control byte is sent by the computer. Connection of the A, B, C, or Control ports to the computer data bus is accomplished by using "port-addressed I /O." Computer address lines AO and Al supply the Port Select signals while addresses A2 through A7 are combined through 8 -input NAND gate IC2, allowing the Ñ and OUT control signals from the TRS -80 to pass to ICI. Address line A2 is inverted by an element within IC4 so that unique I/O ports can be specified without conflicting with the TRS -80 assigned port address of FFH for the cassette recorder. The resulting TRS -80 I/O port addresses for the 8255A's A, B, C, and Control ports are listed in Table I. When power is first applied, the 8255A automatically resets via the SYSRES signal, causing all ports initially to be in the input mode. The reset condition is maintained for about 200 ms by R2 and C4. The 8255A will also be reset whenever the TRS -80 system reset

button is operated. This initializes the unit to a known state and protects any EPROM left in the programming socket from inadvertent pulses which might result from an undefined initial state. As shown in Fig. 5, supply voltages are provided so that several EPROM types are programmable with this circuit. Constant 5, 5, and 12 V are delivered by three -terminal regulators, while 5- and 25.5 -V programming pulses, which must be switched under precise control of the software, are sup-

-

plied by using precision voltage regulators IC7 and IC8 (Fig. 3). Frequency compensation (pin 9) is connected through analog switch IC5 to ground. When a logic 1 is supplied by the 8255A control line (PC4 or PC5), the compensation is allowed to float, turning on the precision regulator. A logic ZERO POPULAR ELECTRONICS

causes the compensation pin to be grounded, turning the precision regula-

DATA BUS D7 -DO

GROUP A PORT A

1/0 PA7-PAO

GROUP A

1/0 PC7-PC4

PORT C UPPER 4

tor off. Input to the 5- and -5 -V regulators is taken from a full -wave rectifier (DI through D4 in Fig. 5), driven by the lower half of the power transformer's secondary winding. The center -tap of that section is grounded, causing the bridge to give both positive and negative outputs of about 8 V. A half-wave rectified input to the 12- and 25.5 -V regulators is supplied at about 30 V by the top three quarters of the transformer secondary winding. (All currents are well below the maximum allowed for

RD

WR

AI AO

RESET cs

-

READ /WRITE CONTROL LOGIC

GROUP

i/O PC3-PCO

regulator operation without heat sinks.) The voltages supplied to some of the EPROM pins depend on whether the device is in the Read or Program mode. Switching between two voltages is done in this case by relay K1 (Fig. 3), which is activated when a 0 on the 8255A control line (PC6) causes current to flow from the 30 -V unregulated supply through voltage- dropping resistor R13, the relay coil, and analog switch IC6 to ground. Diode D6 protects IC6 from voltage spikes caused by relay switching. The relay also switches the LEDI (READ) and LED2 (PROGRAM) mode indicators.

1/0

B

PB7-PBO

CONTROL

8 -BIT INTERNAL

DATA BUS

Fig. 4. Internal logic arrangement of the Intel 8255A. +30V UNREG

D5

IN4004

Personality Modules. Connections to

+12V

ICII LM340-12

REG

pins 18 through 21 of the different EPROMs are unique to each type and must be routed through appropriate "personality" modules. Wiring diagrams for these personality modules are shown in Fig. 6. These can be made using standard 14 -pin headers that will plug directly into the personality module socket of Fig. 3.

C3

SI

+8V UNREG

+5V REG

In Part 2 of this article, we will present construction plans and software information for the EPROM programmer. 0

FI

0.5A

C2

1000uF

r +

I

2

IC9

-5V

3

LM320-5

REG

Fig. 5. Power supply provides several voltages. PMI

PM 2

PM 3

PM

2704 AND 2708

2758 AND 2716

2732

2532

14 2

13

14 2

L

4 5

0

6

9

7

9

5

7

PM 14

2

13

2

13

2

12

3

12

3

12

3

II

4

II

4

10

5

10

5

9

6

13

12

14

4

7,

8

4

i0

5

9

6

8

7

rwwwr Fig. 6. Wiring diagrams for personality modules to accommodate the various types

JULY 1982

-5V

PC3

5V,

PC2

25V,

NC

14 13 12

+12V

5V-25V OV-12V

OV-5V

TO EPROM PIN IB 10

9 9

TO EPROM PIN 19 TO EPROM PIN

20

TO EPROM PIN 21

of EPROMS.

65

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Circuit

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TOUCH - CONTROLLED SOLD-STATE SWITCH

Operation.

Sixty -hertz

power, which is present almost everywhere, is transmitted by the body (fingertip) to a small touchplate. Since the bare end of a wire has enough surface area to function as a touch plate, a plate of any convenient size can be attached to the wire. If the plate is not being touched, RI pulls the input of ICIA low causing a high to appear at the output of ICI A. This reverse -biases DI and allows C2 to remain charged at VDD, Then ICIB senses VDD at its input causing a low to appear at the output of ICIB. When the plate is being touched, a 60 -Hz square wave ranging in amplitude from VDD to ground appears at the output of ¡CIA. During the time that the output of !CIA is low, DI

becomes forward -biased and allows C2 to discharge through DI. While C2 is discharging, the input of ICIB goes to ground causing a high to appear at the output of ICIB. During the time that the output of ICIA is high, DI will again reverse -bias and C2 will start to recharge through R2, keeping a low at the input of ICIB. Therefore, while the plate is being touched, the output of ICIB is always high. Capacitor CI acts as a filter to eliminate frequencies above 60 Hz, which may also be transmitted by the body. For circuits which require only a momentary low, such as the snooze alarm of a clock chip, the second stage of this touch switch can be entirely eliminated and the output of ¡CIA can be directly connected to the snooze alarm input of the clock chip. Supply voltages may range from 3 to 15 V making this touch switch practical for anything from TTL to MOS. Make sure all unused input pins of the 4049 (pins 7, 9, 11, & 14) are connected to VDD or V55. An open input pin will cause that gate to oscillate and draw a great deal of current from the power supply.

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R1-10-MO resistor

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CIRCLE NO. 41 ON FREE INFORMATION CARD 66

POPULAR ELECTRONICS

communications

Popular Electronics Tests

Fox BMP-1O/6O

Scanner Receiver

THE Fox BMP 10/60 scanner receiver covers three frequency bands (3250 MHz, 144 -174 MHz, and 420-511 MHz) with quartz synthesized tuning. The compact FM receiver has a built -in speaker, a membrane -type keyboard, and an LED frequency and mode display. It can be operated from a 12 -V dc source such as a car battery or the ac converter furnished with the radio. The Fox BMP 10/60 can also be used as a personal portable receiver in its optional "Porta -Pac" that serves as a case for the receiver and a holder for either alkaline or NiCd batteries. (The latter are rechargeable from the receiver's ac converter.) The receiver, which is in a molded thermoplastic case, measures 61/2 "W X 9 "D X 15/s "H and weighs 11/2 lb. Suggested retail price is $349.95. The optional car mounting bracket is $9.95, and the Porta -Pac is $29.95.

General Description. In addition to being programmable to any frequency in its designed operating range, the Fox BMP 10/60 is pre-programmed with 60 frequencies in six public service bands, at least some of which can be expected to be JULY 1982

active in most parts of the country. The pre-programmed frequencies include ten "Police 1" channels in the 460 -MHz region, ten "Police 2" channels around 155 MHz, a group of ten "Fire" channels at 154 MHz, ten "Marine/Weather" channels at 156 and 162 MHz (including both NOAA weather channels-162.40 MHz and 162.55 MHz), and two groups of

"Mobile Tel" (telephone) channels

around 152 MHz. The assumed constant availability of the weather channels is used as a set-up convenience since one will always be heard when the receiver is first turned on. The BMP 10/60, though simple to operate after some practice, requires careful study of the instructions that accompany the unit. When the receiver is first turned on by rotating the VOL knob and the SQL knob is turned clockwise to silence interstation noise, one of the ten red LEDs on the front of the receiver will glow to show which of its ten scanning steps is in use. (If the squelch is not set correctly, the receiver will not scan since it interprets the noise to be a received carrier.) To access any group of pre-pro-

grammed channels, the portion of the control panel marked CONTROL is pressed until one long and two short "beeps" are heard and a PR appears in the display window. Then, pressing one of the top panel selector areas (pads) marked with the name of a channel group (such as "Police 1 ") instantly puts the receiver into that range. It scans the ten pre-programmed frequencies until a signal is received. The scanning rate of ten steps per second ensures rapid interception of any receivable activity. Pressing the STEP pad stops the scanning action, and each touch of STEP advances the tuning by one channel. Pressing AUTO returns the receiver to its automatic-scanning mode. The three other control pads modify the receiver's scanning action. ACTION returns the tuning to channel every two seconds to check on its activity. This interrupts the other channel being monitored for only an instant; but if a signal appears on channel 1, the receiver remains there until it leaves. The SKIP mode locks out any selected channels from the scanning /monitor action of the receiver. PAUSE introduces a delay of two 1

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-kHz deviation. Receiver sensitivity is rated by the manufacturer in terms of the input signal required to give a 12 -dB (signal + noise) /noise ratio. The rating is 0.5 µV on the vhf bands and 1µV on the uhf band. In general, our tests confirmed the receiver's ratings, with a sensitivity of 0.49 µV at 144 MHz, 0.27 µV at 174 MHz, and 0.9 µV at both 32 and 50 MHz. The audio output of the BMP 10/60 into an 8 -ohm load (rated at 2 W for 10% distortion) was about 1.5 W at that point and 1.3 W where waveform clipping began to appear (corresponding to about 4.5% distortion). At lower power outputs, the distortion was a constant 3 %. In its scanning mode, the receiver covered about 75 steps per second. All operating modes were checked to confirm their proper action. Everything worked as claimed, and the instruction manual was accurate and complete. 5

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seconds after a carrier drops out before scanning is resumed. These three controls can be applied selectively to any channel, and each is disabled by a second operation of its selector pad. In addition to pre -programmed operation, the BMP 10/60 can be set to any other frequency in its tuning range (resolution is 5 kHz on the two lower bands and 12.5 kHz on the uhf band). Simply place the receiver in a "program" mode by pressing CONTROL until one long beep is ,heard, enter the desired frequency with the keypad numerics, then press ENT/SEEK. This places the selected frequency in the memory channel that was previously accessed with the STEP pad. In any mode of operation, the actual received frequency is always displayed on the LED panel, with six -digit precision. To scan the user -programmed channels, the receiver is put into its "program" mode with CONTROL. Now, in-

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The Fox Scanner Receiver fits neatly in an optional

bracket for mounting under the car dashboard.

stead of selecting a pre -programmed frequency group, the numeral 0 is pressed. Manual tuning in discrete steps of one per second is implemented by pressing and holding ENT /SEEK. An audible "beep" accompanies each frequency step. To reverse the direction of tuning, the pressure on the ENT/SEEK button is released and re- applied. A double "beep" is heard, followed by a normal stepping action, but in the opposite direction. The memories in the receiver are maintained, even with power removed, by a 9 -V battery installed in the case.

NAME

Laboratory Measurements. Our tests

ADDRESS CITY VISA ACCT. NO.

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CIRCLE NO. 18 ON FREE INFORMATION CARD

of the BMP 10/60 were made at the edges of the two lower -frequency bands, using an FM signal modulated with 1 -kHz to a

User Comments. Despite its unusual appearance and method of operation, we found the Fox BMP 10/60 to be a highly effective scanning and monitor receiver. Using only its built -in telescoping antenna (22" long), we were able to receive a large number of stations on all the receiver's bands. In a car, we would expect similar results with a regular whip antenna, and even better performance with a suitable vhf or uhf antenna. As a personal portable radio, installed in its optional Porta -Pac case and battery holder, the Fox BMP 10/60 offers far more versatility than most "pocket size" scanners, without imposing an unreasonable size or weight penalty. -Julian Hirsch CIRCLE NO. 105 ON FREE INFORMATION CARD POPULAR ELECTRONICS

CHECK YOUR SWR... W LE VO.. TALK Standing wave ratio can be measured without interrupting SSB transmission or recalibrating

BY PAUL DANZER

RF

RF CONNECTOR

CONNECTOW7

TO

TO

ANTENNA

TRANSMITTER

FORWARD

VOLTAGE

two -way radio users know, a standing wave ratio (SWR) meter indicates how well the antenna and cable are matched to the transmitter's output. A conventional SWR meter, however, has two distinct shortcomings. It must be calibrated before each SWR reading, and no calibration or reading can be made while the r -f carrier is modulated. (Unmodulated r -f is needed so the meter needle will not AS

fluctuate.) Thus, sideband operators cannot check SWR unless they stop talking and insert an unmodulated carrier. By using the sensing elements of a conventional SWR meter together with a novel display head, as described here, these problems can be overcome. How It Works. A conventional SWR meter typically contains two sensing elements used to sample voltage levels. These voltages are proportional to the forward (transmitted) and reverse (reflected) power level found in the antenna feed line (Fig. 1). A two -position switch is mounted on the front panel of the SWR meter. When it is in the CALIJULY 1982

CALIBRATE

REVERSE

VOLTAGE SWR

AN

.

SWR

CALIBRATION POTENTIOMETER

1. The typical SWR meter measures ratio of forward to reverse voltages.

Fig.

position, forward power is sampled and the SWR meter is set to read full scale. Next, the switch is thrown to the SWR position and the reflected power level is sampled. This second meter reading, always relative to the first meter reading, is taken as the measure of SWR. The meter scale is calibrated according to the formula: SWR = (Vf + Vr)/(Vf Vr) where Vf and Vr are forward and reverse voltages, respectively. BRATE

-

So much for the traditional approach. Now see what happens when LEDs are used to monitor the forward and reverse voltages. The display consists of a simple grid, the horizontal and vertical axes studded with LEDs (Fig. 2). The top (horizontal) row is labeled 1 to 10 and used to measure the forward voltage. The side (vertical) row is also labeled 1 to 10 and used to measure the reverse voltage. Multiple SWR scales are plotted across the grid. To measure SWR, simply find the highest-numbered LED illuminated in each row, trace horizontally and vertically to the intersection, and read the SWR from the appropriate scale. (Note that a modulated signal will cause identical fluctuations in each LED row, but it will still be easy to identify the highest- numbered LED illuminated in each row and find the intersection.) Two integrated circuits are used to convert an ordinary SWR bridge to LED readout -allowing SWR measurement while single -sideband or modulated carrier signals are present

69

check your svvr "ORWARD VOLTAGE

POWER ON (INDICATOR LED)

(HORIZONTAL LED ROW)

!WR

(Fig. 3). The SWR meter is modified by breaking the two leads going to the CALIBRATE /SWR switch. These two wires plus a ground lead are brought out. Two bypass capacitors (CI and C2) are added, and two shielded leads are run to the LED display head, with the shields grounded. Dual potentiometer RI consists of two 100 -kilohm sections on one shaft. It is used as the calibrate control for the system. Trimmers R2 and R3 are used to provide identical dc offsets for the forward and reverse channels.

I.2'1

Fg. 2. The display consists of a simple grid whose horizontal (forward voltage) and vert;cal (reverse voltage) axes are

::1 1:1

scudded with LEDs.

IoQ

0

FORWARD

REVERSE

VOL -AGE

VOLLAGE

Construction Tips. In lieu of a custom printed circuit board, the LED driver can be mounted directly (or with sockets) on a universal breadboard such as the Radio Shack 276 -170 (Fig. 4). Two

CALIBRA'E

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Fig. 3. Two integrated

circuits convert an ordinary SWR meter to provide the LED readout. Use shielded wire between tie old bridge and the new circuir. RIA

PARTS LIST C1 to

C3- 0.01 -p,F, 50 -V dc capacitor

C4- 10 -µF, 50 -d dc capacitor D1 A -D 10A

-2 -2

-V, 20 -mA red LED (Radio Shack 276-041) Dl B -D 106 -V, 20 -mA red LED (Radio Shack 276 -041) D11 -V, 20 -mA red _ED (Radio Shack

-2

276 -041) IC1, IC2- LM3914 LED

diver (Radio

R1- 100 -kf2

dual potentiometer (Radio Shack 271 -1732) R2, R3 -kf2 tr comer (Radio Shack 271 -218)

-2

-1

R4, R5 kfl, 1/2 W R6- 910f1,1/2 W Misc.- Standard SWR meter, shielded wire, 6- to 12 -V dc supply, plastic for faceplate, universal breadboard, etc.

busses are used, one above the ICs for the positive voltage (6 to 12 V) and one below the ICs for ground. LEDs DIA through DIOA, and DIB through DIOB are mounted as shown in Fig. 5. LED DlI acts as a pilot light and is independent of incident or reflected r -f levels. Capacitors C3 and C4 are for power supply bypass. Any 6- to -12 -V dc supply can be used for a power source. A faceplate can be made from a section of rigid plastic, approximately 7" by 7" . Drill two rows of holes to mount the LEDs on half-inch centers. Then glue graph paper to the faceplate with rubber cement and draw the calibration scale on the graph paper. Now give the faceplate a light spraying with "artist fixitive" to keep it from smudging. Each SWR calibration line begins at the "zero" point common to both the forward voltage and reverse voltage axes. The Table gives a number of points for constructing the SWR scales shown in Fig. 2, or you can calculate your own SWR scales from the basic relationship involving forward and reverse voltages given earlier.

Checkout and Operation. After construction, ac power is applied to the SWR meter and (with no r-f present) R2 is rotated so that each of the diodes DIA through DIOA goes on in turn. This test checks out the wiring of the diodes as well as ICI. Now rotate R2 so that DIA goes on, then back off until DIA is just barely extinguished. Repeat this process for the other string of diodes, using R3 to set up Dl B. Checkout and adjustment is now complete. To use the instrument as an ordinary SWR meter (and assuming it is connected in the antenna feed line), key the transmitter and adjust RI so that any one of the horizontal row of diodes is lit. If you chose to have DIOA lit, make sure it is just barely lit (i.e., close to hav-

Shack 276-1707) POPULAR ELECTRONICS

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DISCOVER THE MAGAZINE THAT LAUNCHED THE MICROCOMPUTER INDUSTRY Popular Electronics How Temperature Affects Components

Popular Electronics

world the 8080 microcomputer, but also projects for building the first low -cost modem. The first computer keyboard inter grated with the computer (SOL). The first low -cost voice synthesizer. The first low cost logic analyzer. A low -cost 1802 -based microcomputer (ELF). An 1802 -based EPROM programmer. An automatic line voltage regulator.... As you can see; our construction projects, while not terribly difficult, will keep you at the forefront of technological devel-

Preview of the VHD Video Disc Player Two Projects for Summer

Incredible as it may seem, Popular Electronics launched the microcomputer industry. Back in 1975, we published plans for building the world's finest microcomputer based on the 8080 cpu. These plans

generated incredible excitement -and

started the world thinking about personal computing.

Popular Electronics always helps its readers experience the advances of the future - today. We do it with clearly written, in -depth articles explaining an innovation. Plans for building useful, low-cost projects incorporating the new technology. And reviews of mass- produced equipment when manufacturers finally catch on. Whether it's audio, video, computers, telephones, lasers or something that's just been invented, Popular Electronics will help you have fun with the newest, the most sophisticated, the most innovative electronics technology around.

Helpful buying guides Popular Electronics compares and contrasts electronics gear in handy buyer's guide articles. We discuss features and options, what to look for, and how to get the best value on the market. Recent buyer's guide articles have covered computer printers, cordless home telephones, video cassette recorders, high -tech audio cassettes, video disc players, sophisticated telephones, projection televisions, pocket "beepers," video cameras and oscilloscopes.

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Radio Shack, Sinclair, Xerox), software (dBASE II),audio equipment (Bang & Olufsen, Crown, dbx, Hitachi, JBL, Mitsu-

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Innovative construction projects If you're a do- it- yourselfer, you'll love

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money. And in the future, we'll be bringing you construction projects to help you get more from your computer, including ways to interface your microcomputer with new advances in radio, telephones and video!

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DBA D9A DIOA

me. D28 D3B

046-1I/2' D5B.T

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Fig. 5. Mount the LEDs in horizontal and vertical rows on the front panel as shown here.

Note: Each SWR line starts at origin (Dl tends as shown below.

Diode Intercept D1OA,

018

010A, D28 D1OA, Midway between D3Band D46 D1OA, D5B D1OA, D6B 010A, D76 D1OA, Midway between D78 and D88 010A. 08B DIOA, D9B

1)

and ex-

SWR Label 1.2:1 1.5 :1 2:1 3:1 4:1

5.6:1 7:1 9:1

750 MFD 330 VOLT 2" HIGH X

mewl

volts

D4A D5A D6A D7A

TABLE -SCALE MEASUREMENTS

PAC -TEC SERIES C

VARACTOR

Tij

D2A 03A

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of a custom printed circuit board, the LED driver can be mounted on a universal breadboard as shown here.

Fig. 4. In lieu

D6B

3

(ULTRAVIOLET) 1 G.E.

O R5

5.6

S7.00

6,400 mfd.

2

R3

aR4

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3/4" HIGH

1/2" DIA X 4

4OVDC 3/8" DIA.

4

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ing D9A lit instead of D10A). This

keeps the circuit from saturating. Now note which diode in the vertical column is lit, and read the SWR from the calibration line closest to the intersection extrapolated from the lit diodes. For example, if D1OA is lit in the horizontal row and D5B is lit in the vertical row, the intersection lies on the 3:1 SWR calibration line.

To use the instrument with single sideband, modulate your SSB transmitter and adjust R1 so that horizontal diode DIOA never lights (or flickers only occasionally). Again find the highest number horizontal- and vertical-row diodes which do fully light and extrapolate to find the point of intersection. Read the SWR from the calibration 0 curve closest to the intersection.

=4»

CIRCLE NO.6 ON FREE INFORMATION CARD

POPULAR ELECTRONICS

SOLID-S11E DENCLOPMCNIS By Forrest M. Mims

New Piezoei'ectric Products IN

1880, Pierre and Paul Curie discovered an extraordinary physical phenomenon. They found that if pressure is applied to crystals of quartz, tourmaline, or Rochelle salt, a voltage is produced. They named their discovery the piezoelectric effect. A year later they found that this effect is reversible. If an electric field is applied to these particular crystals, they will either expand or contract.

Typical Applications. Nowadays, we are surrounded by devices and gadgets that exploit the century -old piezoelectric effect. Quartz crystals are found in CB radios and scanners, digital watches and clocks, and computers and TV games. The crystals provide an electromechanical resonance so precise that oscillators designed around them have a stability that varies only a few cycles in a million. Piezoelectric crystals and ceramic elements are used in audio equipment such as phonograph pick -up heads, microphones, high- frequency tweeters, and miniature earphones. Figure 1, for example, shows a magnified view of a piezoelectric wafer that directly drives a tweeter cone. The wafer is a sandwich of two piezoelectric discs separated by a corrugated centervane. When a signal is applied, one disc expands while the other contracts, thus moving the cone to produce a sound. The ultrasonic sound emitted by electrically stimulated, piezoelectric transducers is used to find fish, measure water depth, agitate jewelry- cleaning solvents, repel certain insects, focus cameras, and guide blind people around obstacles. High- intensity, ultrasonic waves from these transducers can scramble an egg

Fig. 1. Piezoceramic sandwich in magnified inset drives a tweeter. (Courtesy Motorola). JULY 1982

without breaking its shell, set cotton ablaze, shatter gallstones, weld metals, and even kill small animals such as fish, frogs and mice. On the other hand, low intensity, ultrasonic sound emitted and detected by piezoelectric transducers can be used to safely view on a CRT the outline of a fetus in its mother's womb. The sparks produced by mechanically stimulated, piezoelectric elements are used to light furnaces, hot -air balloon burners, and the fuel in some cigarette lighters. The ionization produced by high -voltage piezoelectricity is used to neutralize the static charge on phonograph records. A Closer Look at Piezoelectricity. Not all crystals exhibit the piezoelectric effect. Normally a crystal contains an equal number of positive and negative charges and is therefore in a state of equilibrium. In other words, it is.electrically

neutral. If the shape of a crystal is changed by external mechanical pressure, both the positive and negative charges move. At this point the conditions for the flow of an electrical current are present. If, however, the charges move in the same direction, they neutralize or cancel one another and there is no current flow. For a current flow to exist, the charges must move in opposite directions. This happens only in crystals that lack a center of symmetry, and these are the ones that exhibit the piezoelectric effect.

It is important to realize that the piezoelectric effect is always accompanied by the physical movement, via compression or expansion, of the atoms in a crystal. Therefore, a piezoelectric crystal produces a current only when its atoms are in motion. Applying a constant pressure to the crystal will not squeeze out a continuous current! When a piezoelectric element is struck by a small hammer, a pulse of current is produced while the element is being compressed. When the element springs back to its former shape, a second burst of current having a polarity opposite that of the first is produced. An ac voltage can be elicited by applying a fluctuating pressure to a piezoelectric element. The dimensions of a piezoelectric crystal change only when the applied voltage changes. The resulting contraction and expansion is of very small magnitude, often on the order of a few mils or less. Yet the velocity at the surface of a piezoelectric crystal vibrating hundreds of thou-

sands of times per second can be substantial. If, for instance, a crystal surface expands 0.01 inch in 0.00001 second (100 kHz), then the surface of the crystal must move at a velocity of no less than 83.3 feet per second or 56.8 mph. It may, in fact, move considerably faster. Though the current flow produced when a piezoelectric crystal is squeezed is very small, the electromotive force can be on the order of a few hundred or even a few thousand volts. This is sufficient to create a visible arc several millimeters in length. The converse effect, the physical movement of an electrically stimulated piezoelectric crystal, is not nearly so apparent as a highly visible spark. However, its existence can be demonstrated by an appropriate position- sensing transducer, perhaps one which itself employs the piezoelectric effect to generate an output voltage proportional to an applied movement. Its existence may also be made apparent by secondary effects. For example, a rapidly vibrating piezoelectric wafer produces an audible tone.

Piezoelectric Materials. During the past century many crystals that exhibit the piezoelectric effect have been identified. Only a few, however, have been found suitable for practical applications. Of these, quartz is the unquestioned leader. Though the piezoelectric properties of quartz are not nearly so pronounced as those of Rochelle salt, quartz has excellent mechanical properties and good temperature stability. Lithium niobate, a crystal with unique optical properties, is used in some piezoelectric applications. However it is more temperature- sensitive than quartz. Aside from quartz, the most important piezoelectric materials are man -made ferroelectric ceramics such as lead zirconate titanate. These ceramics, unlike quartz and other piezoelectric crystals, are polycrystalline and would therefore seem unsuitable for piezoelectric applications. However, they are given piezoelectric properties during their manufacture by the application of a strong electric field that polarizes the material. More Applications for Piezoelectricity. We've already mentioned some of the better known applications for piezoelectricity, a few of which have been in use for more than fifty years. For instance, many of the applications that depend PIEZOELECTRIC CERAMIC WAFERS

rh

NORMALi

POSITION

ii `` 1

Fig. 2. Piezoelectric bimorph. 73

solid-state developments upon the electrically triggered motion of a piezoelectric element can be traced to the bimorph, the first piezoelectric device invented by the Curie brothers. The basic bimorph shown in Fig. 2 is a sandwich formed by attaching thin piezoelectric bars to either side of a metal strip. Electrically conductive coatings may be applied to either side of one end of the bimorph to form terminals. A voltage applied to the terminals causes one bar to contract in one dimension and expand in the other, while the opposite occurs to the second bar. The resulting forces cause the bimorph to bend. By changing the polarity of the applied voltage, the bimorph will bend in the opposite direction. Recently an entirely new array of applications for the piezoelectric effect was announced by Piezo Electric Products, Inc. (186 Massachusetts Ave., Cambridge, MA 02139). Formed in 1980 to develop new piezoelectric devices, the firm has acquired the piezoelectric product manufacturing facilities of Gulton Industries. So far Piezo Electric Products has announced several new devices developed by Eric and Henry H. Kolm, latter day versions of the Curie bothers and vice presidents of the new firm. The piezoelectric relay or actuator is a miniature solid -state relay which is faster, longer lived and less noisy than conventional electromechanical relays. Figure 3 shows how a piezoelectric relay is constructed. SNAP SPRING

CERAMIC WAFERS

CONTACTS

RELAY

Fig. 3. Piezo Electric Co.'s relay.

The chief drawback of present devices is the requirement of about 40 V for actuation. The piezoelectric relay technology devloped at Piezo Electric Products has been applied to the design of a new dotmatrix printhead. The new printhead uses piezoelectric bending elements instead of solenoids to drive small pins against a carbon ribbon. If successful, a piezoelectric dot -matrix printer should operate at a high speed with considerably less heat production than a conventional dot -matrix printer. A third new application involves piezoelectric quadrature motors and fans. Information from Piezo Electric Products about the design and operation of these devices is sketchy, but the fan is described as operating on the principle of the insect wing and using one -hundredth of the power of a conventional blower of similar output. One application is a min-

iature cooling fan for electronic components. The inverse of the piezoelectric vibrating fan is a solid -state generator that pro-

74

duces power from moving air or gas. According to Piezo Electric Products, "We have proof-of-concept models of electrical generators which operate off the acoustic energy in the exhaust of internal combustion engines. We anticipate that automobile mufflers of this type would replace the alternator and noticeably improve the fuel economy of the engine." The firm has also developed a piezoelectric windmill that generates electricity when piezoelectric elements are vibrated by moving air. The company claims such windmills "... can be effectively made in the form of small units resembling snowfences, highway barriers, or other structures capable of supporting a number of small vanes resembling the leaves of a tree. Such piezoelectric windmills would operate over a wider range of wind velocities than rotary windmills, and hopefully cost less per watt of installed power." Another idea from Piezo Electric Products is a bicycle generator expected to enter production this year. It has much less drag than the conventional generators and directly produces the high voltage required for high- brightness, gas- discharge lamps. Other companies are also developing exotic new applications for piezoelectric technology. Watson Industries (Eau Claire, WI) sells a piezoelectric gyroscope for $295 which (it claims) is superior to laser -ring gyros. The piezoelectric gyro is compact and weighs only about 10 oz. Its sensitivity is sufficient to detect a rotation rate as low as 0.04 degree per second. National Semiconductor (2900 Semiconductor Dr., Santa Clara, CA 95051) has developed a CMOS chip that is powered by an accompanying piezoelectric element. Developed for Gould Inc., the chip derives its power from a rotating tire, and is designed to transmit a coded signal when tire pressure falls below a certain point. Many kinds of piezoelectric accelerometers and force transducers have been developed. There is even a piezoelectric micrometer system manufactured by Polytec Optronics, Inc. (22651 Lambert St., Unit 108, El Toro, CA 92630). This system includes a power supply that provides an adjustable voltage to miniature piezoelectric elements mounted on precision micrometers. Model P -252 provides a total excursion of 25 mm with a piezoelectric fine tuning up to 20 microns (at 0.02 microns per volt). West Germany's Siemens AG has developed a miniature, piezoelectric, isolation transformer. As shown in Fig. 4, a voltage applied to one side of a piezoelectric ceramic wafer induces an acoustic wave that propagates across the wafer to a second pair of electrodes. The voltage produced by the acoustic wave is transferred to the second electrode pair and used to control an external device such as an SCR or TRIAC. One of the products developed by Siemens is available for only 70¢ in large quantities. It is the PZK 20 Piezo Ignition Coupler, which can be used in appli-

PIEZOELECTRIC CERAMIC

OUTPUT VOLTAGE

INPUT VOLTAGE ACOUSTIC WAVE

Fig. 4. Isolation transformer from Siemens.

cations that would instantly destroy the LED in an optocoupler. It's very fast (the acoustic wave travels 2 km /s), it provides very high isolation (the piezoelectric element is an insulator), and it produces its own output voltage. The U.S. address for the components division of Siemens is 186 Wood Ave. S, Iselin, NJ 08830. The address for Siemens AG is Frankfurter Ring 152, D -8000, Munich 46, West Germany. While the recent emphasis in piezoelectric technology has been upon ceramic elements, quartz is still of major importance. The Statek Corporation (512 N. Main, Orange, CA 92668) has made notable advances at both ends of the quartz frequency spectrum. On the low end, Statek has developed a quartz -crystal ocillator that fits within a miniature TO -5 transistor can. A quartz crystal smaller than the point of a sharp pencil provides an oscillation frequency as low as 10 kHz. The crystal and its miniature hybridized circuit can withstand a shock of 1000 g's. On the high end, Statek has developed what it believes is the smallest 1 -MHz microprocessor crystal. The new unit is about one -fourth the size of an 8 -pin mini -DIP. Its calibration accuracy of ±0.05% is achieved by a process in which the miniature crystal is etched from a quartz wafer and fine -tuned to the correct dimensions by laser trimming.

Statek's miniature quartz crystal between leads of an HC -33 can.

Learning More. I'm not aware of any recent books on piezoelectricity. Many electronics texts, however, cover the theory in much more detail than I have in this brief column. Some encyclopedias, particularly those dedicated to science topics, cover the subject quite well. If you want to experiment with piezoelectric crystals of your own making, "Crystals and Crystal Growing" (Alan Holding and Phylis Singer, Anchor Books, Doubleday & Co., 1960) has a chapter containing the recipe for making Rochelle -salt, single crystals larger than a sugar cube. POPULAR ELECTRONICS

the works is a bundled product that will treat the RAM as a solid -state disk system. This board, and possibly the software for it, are expected to be available this month. Even though Burtronix is best known as an R &D house that develops products for others to market, it is also planning to climb on the IBM bus with an $80 prototyping card and an as yet unpriced

OMPU1ER ßns By Carl Warren

Add -Ins and Add -Ons Increase System Performance ANUMBER of established companies are jumping on the microcomputer plug -compatibility bandwagon and are offering a host of goodies to upgrade a system. For example, for the IBM Personal Computer, urged on by an almost limitless market potential, others have developed items ranging from 256K -byte memory boards to expansion chassis for the powerful system -all with the uncharacteristic support of IBM. Even peripheral equipment manufacturers view the IBM machine as an ideal vehicle for new products. One such company, GTCO Corp. has introduced a digitizing option called the Graphic Analysis Package #1. This package consists of a digitizer pad with 0.001 -in. resolution (sizes vary from 11" X 11" to 42" X 60" active area pads), a digitizing stylus, a power supply, a communications interface cable, an operator's manual plus the necessary software on diskette. Prices for the GTCO graphics package range from $1419 for an 11" X 11" tablet to $3025 for a 20" X 20" translucent tablet. The soft-

ware for the graphics option follows the IBM philosophy of using user -oriented menu systems to display 22 predefined functions with room for 11 user -defined functions. Like the GTCO offering, other products being introduced are designed to plug directly into the computer back plane. In some cases, such as Tecmar's PC -Mate Expansion Chassis priced at $945 for chassis and adapters with cables, the idea is to extend the working area of the bus. The Expansion Chassis, is designed to interface to any one of the available expansionslots with a host adapter and extension cables. The bus adapter handles all translation of bus signals and provides buffering and necessary drivers to ensure proper operation of both the primary and expansion bus. Once connected, the expansion bus allows an additional 7 slots for adding memory and peripheral controllers. The chassis comes equipped with a heavy -duty power supply capable of handling an optional 5.25 -in. Winchester disk drive. In addition, the chassis provides convenience power outlets for printers or monitors. Expansion of the bus is only a small part of the offering from Tecmar. The company has developed a total of 20 products, including the expansion chassis, dubbed TecMates. The TecMate seJULY 1982

ries includes a series of RAM cards ranging from a $495 64K -byte card to a $1295 256K -byte card. In addition, you can turn your system into a complete development station by the addition of the E3PROM card ($395) that employs Elec-

trically Erasable Programmable Read Only Memories (EEPROMs). These allow changing ROMable programs under software control so it is not necessary to have an ultraviolet erasing system. In the same line is an IEEE -488 bus adapter ($395) that permits interfacing to a host of test equipment or the similarly priced Lab Tender that provides complete 16- channel, 8 -bit analog-to- digital and digital-to- analog conversion with five timer /counters and three parallel ports. Should your applications be more futuristic, Tecmar even has cards such as the Speech Master ($395) to give your personal computer a voice. The board has a built -in vocabulary of 143 unique words, letters, and word sounds, and according to Dave Wertman at Tecmar you'll be able to purchase additional personality modules to increase the vocabulary by midyear. To really turn the system into a futurists dream, you can purchase the $345 Video Digitizer to convert standard NTSC video signals to digital patterns, and add the $495 Stepper Motor Controller to handle the movement of robotic arms. The idea is to use the IBM Personal Computer to develop an artificial intelligence system that not only performs tasks but recognizes images. No doubt the IBM system will find use in a number of diverse applications, and has wide market potential. However, not all independent design houses are willing to provide as many products as quickly as Tecmar. Typically, most are planning to jump into the market with two products at most. Data Mac Computer Systems, for example, has a memory board that starts at $499 for a 64K RAM board, with the ability to expand to 256K bytes on the same board, for about $1200. Microsoft Consumer Products division is planning a 256K memory add -on, designed by Burtronix, also for about $1200. This RAMCard, employs 64 X RAMs and, like the Data Mac card, its parity can be enabled or disabled depending on the operation. Microsoft is planning to offer more than just the hardware for the price. In 1

extender card. For one -stop shopping for IBM PC add -ons and tools, there is Applied Business Computer Inc. This company offers everything from the AI -1512, 512K -byte RAM card for $1495 to a $3800 5.25 -in. 18M-byte Winchester. They even have an as yet unpriced EPROM programmer, Model AI -7128 that will program 2732s, 2764, and 27128s. If you require CMOS battery- backed memory, they offer the Model AI -1064, 64K board for $850.

Vista Computer on the other hand, is sporting the 576K Multi -Maxicard, that starts out at $1199 for a 256K version and ranges up to $1849 for the full 576K. This board uses just about the entire available memory range permitted without shadowing the system ROM in and out. Another source of IBM PC memory boards is National Technology Sales. This company offers a 256K version for $1495 and 512K configuration for $1995. Dubbed the PC /RAM Stack, the boards have onboard error checking, an average access time of 250 ns, and a typical cycle time of 410 ns. If expanding disk storage is important to you, Interface Inc, has double-sided, double-density drives that provide up to 672K bytes of formatted storage. Two models of drives are available and several combinations of internal and external drives can be used to meet storage requirements. The models include: a single -sided drive with 168K of storage and a double -sided drive with 336K of storage. These can be mixed and matched in any manner. Prices for the drives are $470 for an internal single -sided drive, $570 for a single double -sided drive. Add $100 to each price if you want them configured for external operation.

Apple Owners Get Some Too. Should you have an Apple and would like the functionality of the IBM PC, Coprocessor Inc. has just the ticket with the 88CARD. This $899 items uses an 8088 microprocessor, has 64K of RAM and operates at 5 MHz. The board is designed to work in any Apple slot without burdening the power supply. And if you're wondering, the board uses the same operating systems as the PC and enables you to run all the same programs. Two additional boards that you might want to add to your Apple include: Wesper Microsystems Wizard -BPO, for $179. This card lets you have a printer buffer up to 32K bytes, and is designed to work with all the Apple software, as well as CP /M. What you get is the ability to perform printing while the system is doing something else. Regardless of what your system is, as 75

computers long as you have either a serial RS -232 or 8 -bit parallel port available, you can turn the system into an IEEE -488 bus controller simply by plugging in an ICS Electronics Corp's Model 4825, or 4828 Interface Card. All the commands for 488 operation are implemented onboard. Be aware though that ICS offers these cards to OEMs, and they will more than likely be somewhat above $600 in single

quantities. In operation, the card serves as a

talker /listener, and your computer

thinks it sees either another serial or parallel device. Consequently, writing code to service instruments is a great deal easier since no special 488 drivers are required.

Heath Systems Add -Ins. A few months ago, I happened to call Doug Sauby at Magnolia Microsystems regarding the possibility of adding more than 64K of memory to the Heath /Zenith 89 microcomputer. Doug felt it could be done by employing the memory I/O bit mapping to gain the extra address bits. As a result, Magnolia developed the $595 Invisible Disk. This card employs 64K X dynamic RAM, and extends your total memory space to 176K. In the current implementation, 112K of the added board is treated as a very fast disk drive. About the time you read this column, Magnolia plans to have MP /M fully implemented to permit multi-user /multitasking operations on the machine. Implementing the Invisible Disk is easy. All that is necessary is to remove the 89's cpu card, plug in the Magnolia bit -mapping board and the RAM card, and put it back together again. The most difficult part of the process is removing and reinserting the cpu card. Once you have performed that task, all that is necessary is to link a software module to tell CP /M that the new device is present. You basically set the RAM up as logical device 40; and, using the configuration program, set it to the desired disk name (in our case, drive F:). In operation, you can use setauto to run a Submit program to load the desired program into the semiconductor disk, and begin immediate operation. Ours is 1

set as follows: PIP F: = F:

WS

*

*[VO]

put contents of disk on to F: Log in F: drive run the program-in this case WordStar.

Due to the paucity of space available on Heath add -in boards, Magnolia wasn't able to implement parity checking. Instead they opted for CRC -Cyclic Redundancy Checking, careful layout of the printed circuit board, and close attention to decoupling capacitors. After about two months of operation, we haven't experienced any soft errors; and surprisingly the 89 hasn't overheated. I do want to point out, however, that if your 89 is over two years old and you're thinking of adding such niceties as the Magnolia 8 -in. controller or the Invisible 76

RAM, chances are you will overtax the power supply. We discovered this in one of our 89s that we have had since 1980. The bridge rectifier broke down due to high current, and the secondary in the transformer burned out. Zenith has taken care of these problems in units produced in the last year. The transformer and rectifiers have higher ratings, and all the regulators have heat sinks. So before adding make sure you have adequate power. Another enhancement for the 89 comes from DG Electronics. It offers the Super 89 for $800 for a 64K version and $1400 for a 256K configuration. The board completely replaces the Zenith cpu card, and comes with a 4-MHz cpu, real time clock, parity check on RAM, expanded bus structure, on -board serial I/O port, and is CP /M -HDOS compatible. We asked both the DG folks and the Magnolia designers if the new board would work with Magnolia's disk controllers, but as of this March neither was sure since no actual tests were run. Both design groups saw no problems since the DG board is functionally compatible with the Zenith card. An interesting add -in that you might want to consider for your 89 comes from Artra Inc. The board, called the

FOR MORE INFORMATION For more information on the products described in this article, contact the following manufacturers directly:

Applied Business Computer Co. 2883 E. La Palma Ave. Anaheim, CA 92806 714 -630 -3821 Artra Inc. Box 653 Arlington, VA 22216 703 -527 -0455

Housemaster, provides you with a real time clock, voice recognition, sound synthesizers, BSR X -10 home control, battery backup for the calendar /clock, and dual RS-232 ports. The card, which is available as a kit for $299 or $399 assembled, takes the place of the I/O card. Be aware that things like the RS-232 ports and voice synthesis are options and range in price from $35 to $225 for assembled versions.

Commodore Systems Got CP /M. It seems that everyone wants to have CP /M compatibility, and Small Systems Engineering is providing it with the $895 Z -80 based Softbox. This add -on allows CP/M, RS -232 ports, and an interface to a Corvus hard -disk system, as well as 64K of RAM. The similarly priced Hardbox enhances the Pet disk operating systems allowing one to four Corvus drives to emulate the Commodore floppy -disk system for up to 64 users. It comes with seven utilities including: user reconfiguration, password security, file transfer between hard disk and floppies, diagnostics, and the ability to use a video recorder for data backup. To speed up Commodore BASIC, SSE has PETspeed priced at $350 to give a 30% increase in compiler operation. 0

International Business Machines Corp. Information Systems Div. Box 1328 Boca Raton, FL 33432 305 -998-6007 Magnolia Microsystems Inc. 2264-15th Ave. West Seattle, WA 98119 206 -285-7266

Microsoft Consumer Products Inc. 10700 Northup Way Bellevue, WA 98004 206 -828 -8080

Burtronix

National Technology Sales

18472 Jocotal Lane Villa Park, CA 92667 714 -974 -6171 Coprocessors Inc. 50 West Brokaw Road, Suite 64 San Jose, CA 95110 408 -947-4616 D-G Electronic Developments Co. 700 South Armstrong Denison, TX 75020 214 -465 -7805 Data Mac Computer Systems 680 Alamanor Ave. Sunnyvale, CA 94086 408-735 -0323 GTCO Corp. 1055 First St. Rockville, MD 20850 301 -279 -9550 ICS Electronics Corp. 1620 Zanker Road San Jose, CA 95112 408 -298-4844

Box 401782 Garland, TX 75040 214-349 -8259 Rana Systems 20620 South Leapwood Ave. Carson, CA 90746 213 -538-2353 Small Systems Engineering Inc. 71 Park Lane Brisbane, CA 94005 415 -468-2900

Interface Inc.

Wesper Microsystems

20932 Cantara Street Canoga Park, CA 91304 213 -341 -7914

Sorcim Corp. 405 Aldo Ave. Santa Clara, CA 95050 408 -727 -7634

Tecmar Inc. 23600 Mercantile Rd. Cleveland, OH 44122 216 -464-7410 Vista Computer Co. 1317 East Edinger Santa Ana, CA 92705 714-953 -0523 3188 Pullman Street Costa Mesa, CA 92626 714 -850 -1666

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The editor /assembler software owl la program) designed to simplify the task programs. As your programs become longer and d more complex. the ass-hillier can save you many of programming lime This software includes an editor program that enters the programs you write. makes changes, and saves the programs on cassettes. The assemhler performs the clerical task of Translating symbolic rode into the uimputer-madalrle object code. The editor/ assembler program is available either in cassette or a ROM version. Editor /Assembler (Cassette version. requires Level "B" and Ilk (min.) of RAM we suggest 16k "IAWS' see bove) $69.0 plus $2 P&L ' O Editor/Assembler (ROM version .applied on an Sloe card: requires level B and 4k RAM mm we suggest either Level D or tek "IAWS ") M9.95 plus $2 PSI.8" FLOPPY DISK rema'rh,hl -hmlding block." Add our a" floppy disk when you mss) faster operation. more convenient program a Ice on. an access liiallperhaps . dsofneua programs and program Egx es available You simply slag them into your disk system it accepts all vmgra D Fl ppy Floppy Disk Ca MM.M plus Bí5 2P1.' 0 Diskp Controller Card 11119.95 plus 52 P81.' 0 Disk Drive Cabinet 8 Power Supply Supply 9130 M plus

of writing

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the motherboard and expands the S100 bus to six slats. 0 Level C kit ... $$9.95 plus $2

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COMPLETE FASTERM-64 TERMINAL (includes FASTVID -64 video board ASCII -3 keyboard, steel cabinet and power supply) ... kit $199.95 plus $3 P &I ... wired & tested $249.95 plus $3 P &I ... graphics option: add $19.95 to each of above COMPLETE SMARTERM -80 TERMINAL (includes SMARTVID-80 video board, ASCII -3 keyboard, steel cabinet and power supply) ... kit $299.95 plus $3 P&I ... wired and tested $369.95 plus $3 P &I FASTVID -64 VIDEO BOARD (requires +5 & -12V DC) kit $99.95 plus $3 P &I ... graphics option add $19.95 ... wired & tested $129.95 plus $3 P &I ... graphics option add $19.95 SMARTVID -80 VIDEO BOARD (requires +5 & +( -12V DC) ... kit $199.95 plus $3 P &I ... wired & tested $249.95 plus $3 P &I DELUXE STEEL TERMINAL CABINET ... $19.95 plus $3 P&I ASCII -3 KEYBOARD (requires +5 & -12VDC) ... kit $69.95 plus $3 P &I wired and tested $89.95 plus $3 P &I POWER SUPPLY (powers ASCII -3 keyboard & video boards) ... kit only $19.95 plus $2 P&I ZENITH VIDEO MONITOR (high resolution green phosphor) wired & tested $149.95 plus $6 P&I TELEPHONE MODEM MODEL 103 O/A ... wired & tested $189.95 plus $3

,

Plug in

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TEXT EDITOR/ASSEMBLER

Please send the items checked below:

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LEVEL C Add still more computing power. this 'building block' mounts directly on

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D Drive Cables (set up for two drives)

SPECIAL 1219.95 plus WPM.. O Special Microaoh BASIC Pak (Save 5103.00)-You get Levels A (Terminal Version). 0. D (9k RAM). E. Bk Microsoft in ROM. Intel 8085 User Manual. Level A Moni for Source Listing. and AP -1. 5-amp. power supply (Reg. 5439.70) SPECIAL S329.95 plus 57 Pei O Add Rom -Version Text Editor /Assembler (Requir $99.95 plus S2 Pale levels B and D or 5100 Memory) $279.951

.

Starter 8" DIM System - Includes Level A. R floppy disk controller. one CDC 0" disk-drive. two-drive cable. Iwo S100 connectors: just add your own power supplies. O (Reg. S1065.00) SPECIAL hints and hardware 0 32k Stoner System. $1015.0 5999.65 plus 513 P81.. plus Sto P&I. D 40k Starter System. $1995.85 plus 513 Pel. O 04k Starter System. St145.95 plus 513 Pat' D Add to any of above Explorer steel cabinet. APa five amp. power supply. Level C with two SI0 connectors. disk drive cabinet and power supply. two soh -D wooer.. (Reg tors for ainneding your printer and terminal $225.95) SPECIAL 519995 plus 513 PAI ' C Complete MK Sysem Wired 8 Tested $1650.00 plus $26P81 IT Special! Complete Business Software Pak (Save 5625.00)- Includes CP/M 2.2 Microsoft BASIC. General Ledger. Accounts Receivable. Acrnnnts l':noM Payroll Package (Reg. 511251 SPECIAL 5699.95

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TO ORDER Call Toll Free: 800 -243 -7428 To Order From Connecticut, or For Technical Assistance, Call (203) 354 -9375

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D CP/M 2.2 Disk Operating System, includes Teel Editor/Assembler. dynamic debugger. :md other features that give your Explorer/115 access to th of existing CP /M based programs 5150 no postpaid. NEED A POWER SUPPLY? Consider our AP-1. II ran supply all the power you need for a fully expanded Ex. pbrer /M (note: disk drives hai, Iheirown power supply). Plus the AP -1 his neatly imo the attractive Explorer steel cabinet (see below). APt Power Supply kil (0V bh 5 amps) in deluxe steel cabinet .. ew.M plus 32 Per

D VISA

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Fxp Date

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SiRnaltire Print Name

1

NEED A TERMINAL? We offer you choices. the least expensive one is our Hex 'Keypad /Display kit that displays the information on a calculator-type screen. The )her choice is our ASCII

Address City Stair

7n1,

Keyboard /Computer Terminal kit. that ran he used with either

State

NETRONICS Research & Development Ltd.

Zip

14 333 Litchfield Road, New Milford, CT 06776

II

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EXPLORER /85

services, Dow-Jones stock reports, games, recipes, personal computing w th any level language, program exchanges, electronic bulletin boards ... and more every day!!! Netronics offers two new terminals. both feature a full 56 key /128 character typewriter. style keyboard, baud rates to 19.2 kilobaud, a rugged steel cabinet and power supply. The simplest one, FASTERM -64, is a 16 line by 64 Or 32 character per line unit, with a serial printer port for making hard copy of all incoming data, and optional provisions for block and special character graphics. The "smart" version, SMARTERM80, features either 24 line by 80 characters per line or 16 by 40 characters per line, it offers on- screen editing with page -at-atime printing, 12,000 pixel graphics, line graphics, absolute cursor addressing. underlining, reverse video, one -half intensity and much more ... simply plug them into your computer or our phone modem and be on -line instantly. Use your TV set (RF modulator required) or our delux green -phosphor monitor pictured above. For hard copy just add our matched printer. Price breakthrough!!! Own the FASTERM-64, a complete terminal kit, ready to plug in for lust $199.95 or order the SMARTERM -80 kit for just $299.95, (both available wired and tested.) Be on -line with the million -dollar computers and data services today ... we even supply the necessary subscription forms. More good news: All the components in our terminals are available separately (see coupon), so you buy only what you need!!!

333

FOR ONLY $129.95 Learn Computing From The Ground Up

able, user defined keys, and the ability to count occurrences of specified words or phrases. It also supports an enhanced math mode, split screen option, advanced block operations, and Autolink of multiple files. $175. Address: Muse Software, 347 N. Charles St., Baltimore, MD 21201 (Tel: 301 -659- 7212).

ODMPU1R

soucs

Solomon Technical Director By Leslie

Hardware IBM PC Expansion. These memory expansion boards for the IBM Personal Computer range in size from 64K -bytes to 256K -bytes and feature socketed highspeed dynamic RAM, single board for 256K in any single slot, only seven ICs for control logic, parity checking and error reporting, switch -selectable addressing on any 64K boundary, ability to run IBM diagnostics, compatibility with all

Apple RAM. The DSI 16K RAM Card for the Apple computer is currently available for $99. Address: Davong Systems Inc., 1061 Terra Bella Ave., Mountain View, CA 94043. (Tel: 415 -9657130). CP /M -80 for IBM PC. Baby Blue CPU Plus is a combination of hardware and

software that enables IBM Personal Computers to run virtually any software that is CP/M -80 compatible and written for the 8080/Z80 microprocessor. It plugs into an existing slot, adds 64Kbytes of memory to the system, making it a computer within a computer. Baby Blue runs the programs, and passes the task of communicating with the outside world to the IBM machine. $600. Address: Xedex Corp., 645 Madison Ave, New York, NY 10022 (Tel: 212 -2471400).

IIIIIIIIIIIIUIii

IBM hardware and software, and IBM like documentations. $395 for 64K, $620 for 128K, $845 for 192K, and $1075 for 256K. There is a 64K expansion kit for $225 which boosts boards already in the field. Address: Personal Systems Technology, Inc., 22957 La Cadena, Laguna Hills, CA 92653 (Tel: 714 -859- 8871).

Green Screen Monitors. The PI -1 is a 9" (44 sq. inches) green- screen video monitor that can support 64 characters by 16 lines (80 characters by 24 in some applications). $249. The PI -2 is a 12" (75 sq inches) green- screen video monitor that can support an 80 character by 24 line text display. $275. Both units have 20 MHz bandwidth, with horizontal rate 15.6 kHz. Connection is via SO-239 or RCA phone jack. Both have anti- reflection screen. Address: USI International, 71 Park Lane, Brisbane, CA 94005 (Tel: 415- 468 -4900). Z8O Board. The PRO /80 is a Z80 based

single-board computer featuring the S100 bus, two parallel ports, cassette interface, 1K of RAM expandable on the board to 2K, 1K of EPROM holding the monitor, hex keypad with 8 extra keys, and six 7- segment displays. Requires external 8 -volt, 1- ampere power supply. $169.95. Address: ETCO Electronics Corp., Plattsburgh, NY 12901 (Tel: 514342- 1555). 78

RAM Disk. Designed for the S-100 system or a TRS-80 Model 2 using CP /M 2.2, or the IBM Personal Computer, the

SemiDisk is a high capacity memory board that "looks" like a disk drive to the system, except that it is much faster. It does not require extended addressing or bank switching and all data goes through four I/O ports that can be re- addressed to any of 64 locations. Software is supplied on 8" single- density floppies, 8" double- density TRS-80, 5" NorthStar double density, and IBM 5" formats. 512K -byte SemiDisk is $1995, 1megabyte SemiDisk is $2995. Address: SemiDisk Systems, POB GG, Beaverton, OR 97075 (Tel: 503- 642 -3100).

Software French Programs. If French is your language, you should know that there is now a series of French software programs for the Apple computer. The 24 programs include strategic simulations, interactive fantasies, educational programs, etc. Catalog available from Computerre, C.P. 782, St. Laurent, Quebec, Canada H4L 4W2 (Tel: 514-7479130).

Utility. Super Text allows an Apple II to display an 80 column screen with the use of a Videx Board, insert page headers and footers, multi-file search and- replace, display of disk space availWP

MAIL Utility. Mail -Base is an inquiry/ mailing list that keeps track of up to 32,000 customer records composed of name and address data plus 15 user -defined flags and room for comments. Each customer record is indexed by zip code and user -selectable name key. Each record can be selected by partial or full declaration of any combination of 23 information fields. Selected records may be printed as mailing labels, index and Rolodex cards, user -defined forms, or merged into form letters. For Televideo, Zenith, or any CP /M -based CPU with Zenith Z19 terminal. $199.95 for Microsoft BASIC, $299.95 for compiled version. Address: XtraSoft, Inc., 4910 Roman Drive, Louisville, KY 40291 (Tel: 502 -499 -1533).

VIC20 Software. VICMORSE allows the VIC20 to be used as a cw keyboard keyer and automatic code reader and requires 5K, interface, and I/O connector. $19.95. VICRTTY requires 3K memory expander and is used for radioteletype ham activities. $24.95. The firm also carries numerous game and utility software for the VIC20. Address: RAK Electronics, P.O. Box 1585, Orange Park, FL 32073 (Tel: 904 -264- 0756). CP /M Utilities. The Disk Utility Package for CP /M works with any single user CP /M 2.x system with any diskette size

and format and many hard disks. The menu -driven utilities include DDUMP to examine and patch any byte on any sector, DTEST to test a disk for bad spots which are locked out and reported to printer/terminal, DUSER enables access from one user area to program and /or files stored on other user areas without keeping duplicate copies of disk files, DDUP duplicates disks and is independent of controller, drive, disk size, and format. It will also replace bad sectors on source disk with blank sectors on destination disk. The last utility UNERA recovers from accidentally ERAsed files. $29.95 each or all five $125. Specify format (8" SS /SD, 5" HS Heath /Zenith). Include $8 handling /shipping. Address: Elektrokonsult AS, Konnerudgaten 3, N -3000, Drammen, Norway.

Apple Adventure. The Adventure game for the Apple II uses hi-res graphics which are compressed, and drawn using over 100 colors. It also uses the Votrax Type'N Talk voice synthesizer, producing both pictures and sound. The game wanders through an enchanted world seeking 13 lost treasures, encountering wild animals, magical beings, and other perils and puzzles. $29.95. Address: Adventure International, Dept. G., Box 3435, Longwood, FL 32750 (Tel: 1- 800 -327 -7172).

POPULAR ELECTRONICS

OGR1MMCR'S NOTC BOOK By Jim Keogh

Keeping Time FREQUENTLY, microcomputer software requires the on- screen display of text and /or graphics for specific periods of time. For example, the programmer may want to display a logo, followed by the title of the program, the programmer's name, and the copyright identification, for some short interval. Let's take a look at how display time can be controlled, and then examine a few other interesting BASIC subroutines. Since there is no way that software, even heavily "bugged," can damage the hardware, the reader can experiment with these programs (or any program) to "see what happens." The worst that can happen is an error message being displayed. The most common way to control how long an image appears on screen is by using a simple timing loop. Such a loop instructs the computer to perform a series of calculations, without printing the results of the calculations. The following programs, which can be run on a TRS -80 and Apple II, respectively, will illustrate the timing loop. These computers were TRS-80 10 REM TIMING LOOP

20 CLS 30 PRINT "TIMING LOOP HAS

Let's examine the timing loop a little closer. Line 20 in both programs clears the screen. Clearing the screen is purely a cosmetic event and is not required for proper operation. Line 30 is the statement which we would like to have displayed on the screen for the duration of the selected timing interval. The length of time which the statement will be displayed is controlled by line 40, which begins the timing loop. Line 50 instructs the computer to add 1 to the value of "A." Line 50 is not essential and is shown here to illustrate that the computer can "do something" during the timing interval (e.g., print a statement). After the computer completes the "B" calculation, it moves on to the next "A." The loop then cycles around lines 40, 50 and 60 until the value of the 500th "A" is used. If the upper -end value of "A" used in line 40 is relatively low (e.g., 500), the "padding" represented by step 50 is easily accommodated. But when line 40 is re- stated as "FOR A = 1 TO (any very large number)," line 50 may be omitted. Note that we told the computer to calculate the value for "B." This allows us to keep just the statement we want displayed on the screen without the computer printing the values for "B." The length of time it takes for the computer to complete the timing loop will de-

After the value for the 500th "B" is calculated, the program moves to line 70, which clears the screen. Line 80 then prints "TIMING LOOP HAS ENDED." The following table can be used to create timing loop programs for six different

Seconds 5

10 15

20 25 30

Final Value of A TRS -80 Apple Il 625 1250 2500 1250 1875 3750 5000 2500 6250 3125 7500 3750

time duratons. Simply change the final value of A in line 40 of the previous programs to the value needed to create the desired timing period. For example, make line 40 read: "FOR A = 1 TO 3750" for a 30- second delay with a TRS80.

If you require a longer or shorter time interval than those shown, the program below can be used to determine the final value of A (number of approximate calculations to be made). Note that line 40 of this new program shows screen clearing for both the TRS-80 and the Apple. Select the correct version of line 40 depending on the machine you are using.

STARTED" 40 FOR A = 1 to 500 50 B =A +1 60 NEXT A 70 CLS 80 PRINT "TIMING LOOP HAS ENDED"

APPLE

II

10 REM TIMING LOOP 20 CALL -936 30 PRINT "TIMING LOOP HAS

10 REM THIS PROGRAM DETERMINES THE NUMBER OF CALCULATIONS 20 REM REQUIRED BY A TIMING LOOP FOR A CORRESPONDING 30 REM AMOUNT OF TIME FOR WHICH A STATEMENT WILL BE DISPLAYED

40 (TRS -80) CLS 40 (Apple II) CALL -936 50 PRINT "HOW MANY SECONDS WILL YOUR DISPLAY REQUIRE?" 60 INPUT A 70 (TRS -80) B = A* 125 70 (Apple II) B = A *250 80 (clear screen, see line 40) 90 PRINT "THE NUMBER OF CALCULATIONS YOU NEED IS ";B

STARTED" 40 50 60 70 80

A= =A +1

FOR B

1

TO 500

NEXT A CALL -936 PRINT "TIMING LOOP HAS ENDED"

selected because they are two of the most popular machines. However, the programs will run on all computers equipped for BASIC. JULY 1982

pend upon the BASIC used, the computer "clock" speed, and the number of calculation (iterations) the computer has to perform. In the examples shown, we asked the computer to perform 500 calculations. Due to differences in clock speed, this will take about four seconds for the TRS -80 and approximately two seconds for the Apple II.

A key factor is introduced at line 70, where the desired number of seconds (A) is multiplied by a constant. There are two different constants involved, one for the Z80 CPU used in the TRS -80, and one for the 6502 CPU used in the Apple. That's because these CPUs operate at different clock rates. Again, select the O line that matches your machine. 79

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For an annual membership fee, which is currently $35.00, you too can join thousands of others who have discovered this new approach to mail order marketing, because: -INSTEAD OF mailing several thousand catalogs, every few months, to people with little or no interest in buying through mail- order, EBC will send its members a personalized 3 -ring binder with hundreds of pages of specifications and pricing for more than 3500 items in stock. -INSTEAD OF re- issuing, every so often, the same catalog with only a few minor changes, you will only receive, on a quarterly basis, updates containing information on new items and revisions on current ones. -INSTEAD OF having the customer pay for the expensive cost of regular monthly advertising and mass distribution of catalogs, EBC members pay the lowest possible prices for their electronic needs, oftentimes recovering the full cost of their annual membership from the savings realized through their first order. In addition to what is listed here, we stock the complete lines of AP PRODUCTS, OK MACHINE & TOOLS, VECTOR ELECTRONIC COMPANY, Pre -stripped Wrapping Wire in 6 colors and 15 lengths, Resistors, Capacitors, IDCs, Linear ICs, LED Lamps and Displays, LCDs, Micro -Computers and Peripheral Devices, with thousands of additional items to be offered in the near future, ALL AT SUPER LOW PRICES! COMPARE OUR PRICES AND JOIN EBC TODAY by calling 800 -325 -0101. You can place your first order at the same time and charge it all to your MASTERCARD or VISA, or authorize us to ship C.O.D. Our 30 -Day money -back Guarantee will assure you that you cannot go wrong!

DIGITAL INTEGRATED 74147 74148 74150

74x x 7400 7401

7402 7403 7404 7405 7406 7407 7408 7409 7410 7411

7412 7413 7414 7416 7417 7420 7421

7423 7425 7426 7427 7430 7432 7437 7438 7439 7440 7441

7442 7443 7444 7445 7446 7447 7448 7450 7451

7453 7454 7459 7460 7470 7472 7473 7474 7475 7476 7480 7482 7483 7485 7486 7489 7490 7491

7492 7493 7494 7495 7496 7497 74104 74107 74109 74120 74121 74122 74123 74125 74126 74132 74141 74145

$ 0.89

0.62 0.54 0.32 0.32 0.32 0.53 0.32 0.38 0.38 0.38 0.48 0.48 0.48 0.48

74151

$ 0.15 0.15 0.15 0.15 0.17 0.17 0.20 0.20 0.17 0.17 0.15 0.17 0.17 0.24 0.35 0.19 0.19 0.15 0.17 0.18 0.18 0.18 0.18 0.15 0.18 0.18 0.18 0.18 0.15 0.60 0.31

0.50 0.50 0.50 0.46 0.46 0.46 0.15 0.15 0.15 0.15 0.15 0.15 0.21 0.21 0.21 0.21

0.27 0.21

74152 74153 74154 74155 74156 74157 74158 74160 74161 74162 74163 74164 74165 74166 74167 74170 74173 74174 74175 74176 74177 74178 74179 74180 74181 74182 74184 74185 74188 74190 74191 74192 74193 74194 74195 74196 74197 74198 74199 74221 74251 74279 74283 74290 74293 74298 74365 74366 74367 74368

0.51 0.51

0.54 1.06

0.84 0.58 0.41

0.40 0.47 0.47 1.00 1.00

0.48 1.02 0.48 1.06 1.06 2.10 0.50 0.50 0.50 0.50 0.48 0.36 0.47 0.47 0.63 0.63 0.40 0.57 0.50 0.99 0.54 0.54 0.50 0.36 0.36 0.36 0.36

0.22 0.34

1.08

0.47 0.20 0.22 0.60 0.24 0.27 0.35 0.30 0.30 0.35 0.53 0.45

74Cx x 74C00 74CO2 74C04 74C08 74C10 74C14 74C20 74C30 74C32 74C42 74C48 74C73 74C74 74C76 74C83 74C85 74C86 74C89 74C90 74C93

S 0.20

0.20 0.20 0.20 0.20 0.46 0.20 0.20 0.20 0.72 0.96 0.46 0.46 0.44 0.89 0.89 0.23 2.15 0.71 0.71

S 0.82

0.44 1.37

2.04 1.37 0.71 0.71 0.71 0.71 0.71

0,77 0.65 0.65 0.65 0.72 0.72 0.71

4.08 0.96 0.34 0.34 0.34 0.34 5.10 0.34 0.34 0.76 1.38

3.27 0.72 0.89 3.90 3.90 3.90 3.90 0.35 0.35 0.35 0.35

74Fxx 74F00 74F02 74F04 74F08 74F10 74F11

74F20 74F32 74F64 74 F74

0.41

0.50 0.20 0.95 0.30 0.36 0.30 0.30 0.38 0.34 0.38

74C95 74C107 74C151 74C154 74C157 74C160 74C161 74C162 74C163 74C164 74C165 74C173 74C174 74C175 74C192 74C193 74C195 74C200 74C221 74C901 74C902 74C903 74C904 74C905 74C906 74C907 74C908 74C909 740910 74C914 74C918 74C925 74C926 74C927 74C928 80C95 80C96 80C97 80C98

74F86 74F109 74F138 74F139 74F151 74r153 74F157 74F158 74F164 74F175 74F181 74F182 74F190 74F191 74F194 74F241 74F243 74F244 74F251 74F253 74F257 74F350 74F352 74F353 74F373

S 0.39 0.39 0.45 0.39 0.39 0.39 0,39 0.39 0.39 0.44 0.58 0.81 0.87 0.87

0.87 0,87 0.87 0.87 1.35 1.35

2.90 1.50 2.36 2.36 1.17

2.78 2.78 1.80 0.94 0.94 0.94 2.10 0.94 0.94 2.34

74F374 74F521 74F533 74F534

$ 2.34

2.04 2.34 2.34

74LSx x 74LS00 74L501 74LS02 74L503 74L504 74L505 74L508 74LS09 74LS1O 74LS11 74L512 74LS13 74LS14 74LS15 74LS20 74L521 74LS22 74LS26 74LS27 74L530 74LS32 74LS33 74LS37 74LS38 74LS40 74LS42 74LS47 74L548 74L549 74LS51 74LS54 74L555 74L573 74LS74 74LS75 74L576 74LS78 74L583 74LS85 74LS86 74LS90 74L592 74LS93 74LS95 74LS107 74LS109 74LS112 74L5113 74LS114 74LS122 74LS123 74LS125 74L5126 74LS132 74LS133 74LS136 74L5138 74LS139 74L5151 74L5152 74LS153 74LS154 74L5155 74L5156 74LS157 74LS158 74L5160 74L5161 74L5162 74LS163

$ 0.15 0.15 0.15 0.15

0.17 0.17 0.16 0.16 0.15 0.17 0.17 0.21

0.35 0.15 0.15 0.15 0.15 0.18 0.16 0.15 0.17 0.32 0.18 0.18 0.15 0.37 0.60 0.51

0.54 0.15 0.15 0.15 0.21 0.21

0.29 0.23 0.24 0.40 0.54 0.24 0.33 0.33 0.33 0.40 0.22 0.22 0.24 0.24 0.24

CIRCUITS 74LS164 $0.51 74LS165 0.51 74LS168 0.57 74LS169 0.57 74LS170 0.84 74LS173 0.54 74LS174 0.35 74LS175 0.35 74L5181 1.36 74L5190 0.58 74L5191 0.56 74LS192 0.56 74L5193 0.56 74LS194 0.64 74L5195 0.40 74L5196 0.56 74LS197 0.56 74L5221 0.58 74LS240 0.63 74LS241 0.63 74LS244 0.63 74LS245 0.63 74L5247 0.59 74LS248 0.59 74LS251 0.40 74L5253 0.49 74L5257 0.41 74L5258 0.41 74L5259 0.94 74LS260 0.21 74LS266 0.27 74LS273 0.88 74LS279 0.29 74LS283 0.47 74LS290 0.58 74LS293 0.58 74L5295 0.54 74L5298 0.54 74LS352 0.58 74LS353 0.58 74L5365 0.33 74L5366 0.33 74LS367 0.33 74LS368 0.33 74L5373 0.80 74LS374 0.80 74LS375 0.56 74LS377 0.80 74LS378 0.70 74LS379 0.70 74L5386 0.28 74LS390 0.68 74L5393 0.68 74LS395 1.05 74L5447 0.37 74L5490 1.02 74L5670 1.14

0.41

0.47 0.33 0.33 0.42 0.26 0.26 0.45 0.45 0.36 0.36 0.36 0.72 0.41 0.41 0.41 0.41 0.51 0.51 0.51 0.51

74Sx x 74500 74501 74502 74503 74504 74505 74508 74509 74510 74511 74515

74520 74521 74522 74530

S 0.23 0.23 0.23 0.23 0.24 0.24 0.24 0.24 0.23 0.23 0.23 0.23 0.24 0.23 0.23

74S32 74540 74550

S 0.28

0.24 0.24 0.24 0.24 0.24 0.24 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.52 0.23 0.24 0.42 0.74 0.74 0.26 0.66 0.66 0.66 0.66 1.48 0.87 0.87 2.73 0.82

74551 74560 74564 74565 74574 74576 74578 74586 745112 749113 745114 745132 745133 745134 745135 745138 745139 745140 745151 745153 745157 745158 745161 745174 745175 745181 745182 745189 745194 745195 745206 745240 745253 745257 745258 745280 745289 745387 93500 93505 93510 93512 93516 93541 93542 93543 93546 93562

1.83 1.07 1.07 2.48 1.29 0.63

0.60 0.60 1.14

3.05 2.54 1.08 1.25 1.88

0.74 1.8S 2.73

0.82 3.24 0.84 1.44

4x x x 4000

S 0.20

4001

0.17 0.17

4002 4006 4007 4008 4009 4010 4011

4012 4013 4014 4015 4016 4017 4018 4019 4020 4021

4022 4023 4024 4025 4026 4027

0.61 0.20

0.57 0.27 0.27 0.17 0.17 0.30 0.50 0.50 0.28 0.54 0.49 0.27 0.58 0.48 0.56 0.17 0.40 0.17 1.20 0.36

4028 4029 4030 4031 4034 4035 4040

S 0.45

4041

0.54

4042 4043 4044 4045 4046 4047 4048 4049

0.51

4050' 4051

4052 4053 4060 4066 4068 4069 4070 4071

4072 4073 4075 4076 4077 4078 4081 4085 4086 4089 4093 4099 4502 4503 4507 4508 4510 4511

4512 4516 4518 4519 4520 4527 4528 4539 4555 4556 4582 4584 4702 4703 4704 4705 4706 4720 4723 4724 4725 40014 40085 40097 40098 40106 40160 40161 40162 40163 40174 40175 40192 40193 40194 40195

0.58 0.23 1.12 1.30 0.65 0.58

0.54 0.51

0.64 0.63 0.64 0.28 0.28 0.28 0.54 0.54 0.54 0.59 0.27 0.21 0.17

0.20 0.17 0.17 0.17 0.17 0.53 0.30 0.24 0.17 0.39 0.39 1.07

0.36 0.80 0.27 0.36 0.42 1.49 0.59 0.53 0.53 0.59 0.59 0.30 C.54 0.71 0.63 0.53 0.46 0.46 0.59 0.39 3.87

4.50 3.98 5.04 5.32 5.32 0.78 0.78 2.15 0,39 0.89 0.38 0.38 0.39 0.71 0.71 0.71 0.71

0.65 0.65 0.72 0.72 0.71 0.71

DIODES & TRANSISTORS PRICE PER

DEVICE TYPE

10

1N270 1N914 1N4001 1N4002

$1.30 0.26 0.49 0.52

1N4003 1N4004 1N4005 N4006 1N4007 1N4148 2N2218 2N2218A 2N2219 2N2219A 2N2220 2N2221 2N2221A 2N2222 2N2222A 2N2369 2N2369A 2N2484 2N2904 2N2904A 2N2905 2N2905A 2N2906 2N2906A 2N2907 2N2907A 2N3019 2N3704 2N3903 2N3904 2N3905 2N3906 2N4033 2N4123 2N4124 2N4400 2N4401 2N4402 2N4403 MPS2222 MPS2222A MPS2369 MPS2907 MPS2907A MPSA42 MPSA43 MPSA92 MPSA93 1

40-PIN

$90.00 17.50 34.00 36.00 38.00 40.00 44.00 48.00 55.00 17.50 220.00 240.00 220.00 240.00 180.00 180.00 185.00 180.00 185.00 180.00

$10.80 2.10 4.08 4.32

4.56 4.80 5.28 5.76 6.60 2.10 26.40 28.80 26.40 28.80 21.60 21.60 22.20 21.60 22.20 21.60 22.20 21.60 26.40 28.80 26.40 28.80 21.60 22.20 21.60 22.20 26.40 7.20 7.20 7.20 7.20 7.20 39.60 7.20 7.20 7.20 7.20 7.20 7.20 7.20 7.80 7.20 7.20 7.80 22.20 21.60 22.20 21.60

0.55 0.58 0.64 0.70 0.80 0.26 3.17 3.46 3.17 3.46 2.60 2.60 2.67 2.60 2.67 2.60 2.67 2.60 3.17 3.46 3.17 3.46 2.60 2.67 2.60 2.67 3.17 0.87 0.87 0.87 0.87 0.87 4.76 0.87 0.87 0.87 0.87 0.87 0.87 0.87 0.94 0.87 0.87 0.94 2.67 2.60 2.67 2.60

SOLDER -TAB NO. OF PINS 8-PIN 14-PIN 16-PIN 18-PIN 20-PIN 22-PIN 24-PIN 28-PIN

1000

100

185.00 180.00 220.00 240.00 220.00 240.00 180.00 185.00 180.00 185.00 220.00 60.00 60.00 60.00 60.00 60.00

330.00 60.00 60.00 60.00 60.00 60.00 60.00 60.00 65.00 60.00 60.00 65.00 185.00 180.00 185.00 180.00

SOCKETS

PRICE PER

$0.09 0.10 0.11

0.13 0.15 0.16 0.17 0.20 0.29

$0.79 0.91

1.00 1.17 1.29 1.38 1.52 1.82 2.58

1000

100

10

7.15 8.25 9.08 10.59 11.69 12.48 13.75 16.50 23.38

$

S

65.00 75.00 82.50

96.25 106.25 113.45 125.00 150.00

212.50

0> Hitachi Denshi,Ltd. OSCILLOSCOPES MODEL V-

1

5

1

B

V-152B V-202 V-301

V-302B V-352 V-550B V-1050

DESCRIPTION 15MHZ, SINGLE TRACE 15MHZ, DUAL TRACE 20MHZ, DUAL TRACE 30MHZ, SINGLE TRACE 30MHZ, DUAL TRACE 35MHZ, DUAL TRACE 50MHZ, DUAL TRACE 100MHZ, QUAD TRACE

30 -DAY

PRICE S

427.50 551.25 637-50 558.75 746.25 862.50 1,308.75 1,792.50

VOLTAGE DEVICE TYPE LM317KC

LM3I7UC UA7805KC

VREG VOLT ADJ. ADJ.

UA7805UC UA7806UC UA7808KC UA7808UC UA7812KC UA7812UC UA7815KC UA7815UC UA7818KC UA7818UC UA7824KC UA7824UC UA78GKC UA78GU1C UA78H05KC UA78H12KC UA78HGKC UA78P05KC UA78S40PC* UA7905KC UA7905UC UA7908KC UA7908UC UA7912KC UA7912UC UA7915KC

UA79I5UC UA79GKC UA79GUIC UA79HGKC

1.5 1.5

5 5

PRICE PER

STYLE

TO-220 TO-3 TO-220 TO-3 TO-220

6 8 8

12

12 15 15

24 24

ADJ. ADJ.

1.17

0.60

0.60

-5

TO-220 TO-3 TO-220

0.60

TO-220

0.60

TO-220 TO-3 TO-220 TO-3

0.60

1

-5 -8

1 1

-8

1

-12 -12 -15 -15

1 1

1

1 1

5

5.45 11.35 7.57 45.38 52.94 51.43 90.75 17.40 10.59 5.45 10.59 5.45 10.59 5.45 10.59 5.45 11.35 7.57 51.43

0.60

1.25

0.84 5.00 5.83 5,66 9.99 1.92

1.17

1.17

0.60

1.17

TO-3

1

-ADJ. -ADJ. -ADJ.

1.17 0.60 1.17

TO-3 TO-3 TO-3 TO-3 16-DIP TO-3

10 1.5

5

ADJ.

1.17

TO-220 TO-3 TO-220 TO-3 TO-220 TO-3 TO-220 5 5 5

5

12

ADJ.

5.45

10.59 5.45 10.59 5.45 10.59 5.45 10.59 5.45 10.59

1.17

0.60

TO-3

18 18

12.10 10.59 5.45

1.34 1.17

0.60 0.60

TO-3

1.17 1.25

0.84 5.66

1000

$151.25 $1,375.00 1,000.00 110.00 875.00 96.25 49.50 450.00 450.00 49.50 875.00 96.25 450.00 49.50 875.00 96.25 450.00 49.50 875.00 96.25 450.00 49.50 875.00 96.25 450.00 49.50 875.00 96.25 450.00 49.50 937.50 103.13 625.00 68.75 412.50 3,750.00 4,375.00 481.25 4,250.00 467.50 7,500.00 825.00 158.13 1,437.50 875.00 96.25 450.00 49.50 875.00 96.25 450.00 49.50 875.00 96.25 450.00 49.50 875.00 96.25 450.00 49.50 937.50 103.13 625.00 68.75 4,250.00 467.50

$16.64

51.84

TO-3 TO-220 TO-3 TO-220

100

10

1

*SWITCHING REGULATOR

& SUPPORT

MICRO-PROCESSOR DEVICE TYPE Z80A-CPU Z80B-CPU Z80A-DMA Z80A-P10 280A-CTC Z80A-S10/1 Z80A-S10/2 Z80A-S10/9

SPEED 4 MHZ

2708 2716 2732

MONEY -BACK GUARANTEE

6

4 4 4 4 4

450 NS 450 NS 450 NS

DEVICES

PRICE PER

CLOCK/

MHZ MHZ MHZ MHZ MHZ MHZ 4 MHZ Z80A-DART 4 MHZ Z8001-CPU 4 MHZ 1.0 MHZ 6800 MHZ 1.5 68A00 2.0 MHZ 68B00 1.0 MHZ 6802 1.0 MHZ 6809 450 NS 6810 350 NS 68A10 250 NS 68B10 1.0 MHZ 6820 1.0 MHZ 6821 1.5 MHZ 68A21 2.0 MHZ 68B21 1.0 MHZ 6840 1.5 MHZ 68A40 2.0 MHZ 68B40 1.0 MHZ 6844 1.0 MHZ 6845 1.0 MHZ 6847 1.0 MHZ 6850 1.5 MHZ 68A50 2.0 MHZ 68B50 1.0 MHZ 6852 1.5 MHZ 68A52 2.0 MHZ 68B52 1.0 MHZ 6854 1.5 MHZ 68A54 2.0 MHZ 68B54 1.0 MHZ 6856 1.0 MHZ 68488 450 NS 2114L 200 NS 2114L-2 150 NS 2114L-1 150 NS 6116-3 4116-3 200 NS 150 NS 4116-2

would like for you to take a closer look at your Membership Binder and even try an order with E.B.C., so you may decide for yourself how valuagle a service this is. Therefore, we guarantee to refund the full Membership Fee of any new member who returns his Binder to us within 30 days from the date of receiving it. We

1MAX AMP

REGULATORS

PKG.

3.20 8.79 10.39 4.24 4.24 17.25 17.25 15.02 7.99 94.80 4.80 4.86 5.04 4.80 14.38

S

S

1.52 1.59 1.60

2.00 2.00 2.24 2.56 3.60 3.67 4.00 8.79 8.79 6.39 1.92 1.99 2.24

2.24 2.56 3.20 5.99 6.71 7.43

31.95 6.39

1.60 2.00 2.50 9.19 1.76 1.84 3.28

5.20 14.45

P.O. Box 617

$

156.82 156.82

136.49 72.60 ---

$

---

396.00 401.50 415.80 396.00 1,188.00 125.40 130.90 132.00 165.00 165.00 184.80 211.20 297.00 302.50 330.00 726.00 726.00 528.00 158.40 63.90 184.80 184.80 211.20 264.00 495.00 554.40 613.80

43.56 44.17 45.74 43.56 130.68 13.80 14.40 14.52 8. 15

18.15 20.33 23.24 32.67 33.28 36.30 79.86 79.86 58.08 17.43 18.03 20.33 20.33 23.24 29.04 54.45 60.99 67.52 290.40 58.08 14.52 18.15 22.60 83.49 15.98 16.70 29.77 47.19 131.34

LIJIJJLIIIJ A SUBSIDIARY

264.00 726.00 858.00 349.80 349.80 1,425.60 1,425.60 1,240.80 660.00

29.04 79.86 94.38 38.48 38.48

1

1000

100

10

1

°

1

---

528.00 132.00 165.00 205.95 759.00 145.20 151.80 270.60 429.00 1,194.00

2,400.00 -------

3,180.00 3,180.00 -------

------

`--

3,600.00 3,650.00 3,780.00 3,600.00 ----

1,140.00 1,190.00 1.200.00 1,500.00 1,500.00 1,680.00 1,920.00 2,700.00 2,750.00 3,000.00 ----

------

1,440.00 1,490.00 1,680.00 1,680.00 1,920.00 2,400.00 ----

---

----------

1,200.00 1,500.00 1,872.00 ----

1,320.00 1,380.00 2,460.00 3,900.00 ----

EUIW`V' IJLI.

OF ECI -USA, INC.

Columbia, MO 65205

U.S.A.

(314) 474 -7400 CIRCLE

NO.

47

ON

FREE

INFORMATION

CARD

EIMPCMMCFI1ER'S

RNCR

By

Forrest M. Mims

Experimenting with Piezoelectric Devices Part

1.

Microphones, Pushbuttons, and Ceramic Filters

j

NHEN certain crystals and ceramics are mechanically flexed, a voltage is produced. This phenomenon is known as the piezoelectric effect. The effect is reversible, too. This means that piezoelectric crystals and ceramics will contract or expand when a voltage is applied across them. In this two -part column, we'll experiment with devices that exploit the electrical output of a mechanically flexed or stressed piezoelectric element. And we'll work with those that depend on the mechanical motion of an electrically excited piezoelectric element. The Piezoelectric Microphone. The so- called crystal microphone is a piezoelectric acoustic transducer. Early crystal microphones used a Rochelle-salt crystal element. Today the piezoelectric element in many of these microphones is a polarized ceramic wafer about the size of a fingernail. The ceramic is easy to mass produce, and is stronger and more moisture resistant than Rochelle salt. You can learn much about the operation of a piezoelectric microphone with the help of an oscilloscope. Connect the leads of the microphone directly to the scope's probe. Set the vertical sensitivity to about 0.1 V /div. Adjust the sweep speed to about 1 ms /div. First, speak or whistle into the microphone. The scope's CRT will display a visual analog of the sound; and, depending upon the proximity of the microphone to your mouth, the amplitude will range from about 0.1 to 0.5 V. Since the waveform overlaps the no- signal centerline, it is ac in nature. Next, rap the microphone with a pencil or thump it with a finger. If the microphone is an economy version, the scope's CRT will display a ringing pulse with an initial peak of perhaps 40 or 50 V. The duration of the initial pulse will be about 0.1 ms. A better designed, highly damped, piezoelectric microphone will produce only a very low voltage when tapped or thumped. This is because its element is designed to prevent inadvertent high -voltage spikes that might damage the input stage of a preamplifier. This could happen if a microphone were dropped or otherwise given a strong blow. You can perform a dramatic experiment to demonstrate the high -voltage output of a highly stressed piezolectric microphone element by connecting the leads from the microphone to a neon glow lamp as shown in Fig. 1. Select a very cheap or discarded microphone (perhaps one with a damaged foil diaPRESSURE

1. Flashing a neon lamp with a crystal microphone element.

Fig.

82

phragm), since it is necessary to remove the microphone's cover. Tap the center of the foil diaphragm with a pencil or thump it with a finger, and the lamp should flash. The voltage pulse will be up to a millisecond wide and its amplitude may reach a few hundred volts! It's not necessary to remove the diaphragm to conduct this experiment. However, if you wish to remove the foil, peel it from around the edge of the microphone case first. Then carefully pull it away from the central metal support that is attached to the piezoelectric element. Small scissors may help. If you remove the foil, do not directly strike the element to light the neon lamp. Instead, strike the metal support bar that bridges two opposite corners of the element and provides a mounting point for the diaphragm. Be careful! The sole support for the piezoelectric element is probably a pair of rubber vibra-

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Fig. 2. Vernitron 3652 piezoelectric

high- voltage pushbutton.

tion- damping bumpers on two opposite corners of the element. The element is easily detached from these supports. Also, the two leads emerging from one side of the element are very fragile. The Piezoelectric Pushbutton. Piezoelectric pushbuttons are used to ignite the fuel of some cigarette lighters, laboratory burners, and home furnaces. They produce a brief spike of up to 18,000 V and can make an arc up to 3/,e in. in length. For several years I've enjoyed experimenting with a Model 3652 high -voltage pushbutton made by Vernitron Corporation (Piezoelectric Division, 232 Forbes Road, Bedford, OH 44146). A similar device made by Vernitron is used as a solid -state igniter for outdoor cooking grills. The company has also manufactured hundreds of thousands of 0.1 -inch, piezoelectric, ceramic cubes used to power the flash in compact cameras. A pictorial view of the 3652 high- voltage pushbutton is shown in Fig. 2. The piezoelectric element is a compact slug about 5/8 by %g in. Most of the unit's size is taken by the spring loaded trip hammer that strikes the piezoelectric element. To operate the unit, the pushbutton is pressed downward with a force of a few pounds. This compresses the upper spring and moves the cam toward the pin on the trip hammer. When POPULAR ELECTRONICS

experimenter's corner SG/

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7VL sOV NEX

M'ERTER

f SV INSERT /oa Loss /1/ 6

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/ the cam pushes the pin into the drive slot, the hammer is triggered and slammed with a good deal of force against the piezoelectric element. When the pushbutton is released, the lower spring, which was compressed by the downward motion of the hammer, returns the hammer to its resting position where it is again ready to be driven against the piezoelectric element. The arc produced by the piezoelectric pushbutton can be viewed by placing the output electrode near the unit's metal frame. For best results, the arc should be viewed in subdued light or against a dark background. Unless you want to feel a potent tingle, keep you fingers away from the output electrode when the button is pressed! An interesting experiment is to connect a piezoelectric pushbutton to a long xenon flash tube. When the button is pressed, a thin violet arc will immediately appear between the tube's electrodes. With suitable rectification it should be possible to use a piezoelectric pushbutton to charge a capacitor to a very high voltage. Of course the capacitor would have to be rated for the expected voltage. This might make possible a very simple power supply for Geiger counters and infrared image- converter tubes. An 18,000 -V piezoelectric pushbutton is available for $9.95 plus $2.45 for packing and guaranteed delivery from Edmund Scientific (101 E. Gloucester Pike, Barrington, NJ 08007). Specify catalog number 42,102 when ordering. The Ceramic Filter. The ceramic filter, a most unusual piezoelectric device, is dependent upon the mechanical resonance of a piezoelectric ceramic wafer. When a signal is applied to its input, a surface wave is induced in the ceramic. If the frequency of the wave matches the resonant frequency of the ceramic, the wave will travel along the surface of the ceramic where it induces a piezoelectric voltage at a second pair of electrodes. Otherwise no signal is passed through the filter. In effect, then, the ceramic filter functions like a frequency-selective, isolation

transformer. Ceramic filters are widely used as 455 -kHz intermediate range filters in AM radio receivers. They are also used as 10.7 MHz filters in FM receivers and television sets. At these frequencies, the size of the filter is much smaller than an equivalent electronic filter. For example, a typical 455 -kHz ceramic filter is a disc 0.2 in. across and from 0.1 to 0.4 in. thick. If the signal applied to a center electrode and a common electrode on the back side of the disc is at or very near 455 kHz, then the disk will vibrate and induce an electrical signal at a third electrode around the upper edge of the disk. Figure 3 is a circuit that demonstrates the operation of a 10.7-

0

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Fig. 5. Measured bandpass of a 10.7 -MHz ceramic filter.

MHz ceramic filter such as the SFE 10.7MA5-A made by muRata Corporation of America (1148 Franklin Road, S.E., Marietta, GA 30067) and available for about one dollar from Radio Shack. In operation, two inverters in a 7404 or 74LSO4 hex inverter form a high- frequency oscillator whose output signal is buffered by a third inverter and fed into a ceramic filter. The frequency of the oscillator, which is determined by R1, can be adjusted from about 9 to 19 MHz with the component values shown. Much lower frequencies can be produced by increasing the value of Cl. Figure 4 shows the signal from the oscillator before and after

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experimenter's corner RI adjusted to provide the filter's peak frequency response. Note that the output signal appears to have about twice the amplitude of the input signal. Actually, the output signal is an ac version of the single -polarity input signal, hence the apparent doubling of its amplitude. Also note that the output signal is phase delayed and is a much smoother, cleaner version of the input signal. The input signal might be cleaned up somewhat by optimizing component placement and using direct, point -to -point wiring instead of a solderless breadboard. Why is the output better shaped than the input? The acoustic wave that travels across the surface of the ceramic dampens imperfections in the input signal. How effective is a ceramic filter? Figure 5 is a frequency -response plot made with the help of the circuit in Fig. 3 and an oscillocope. Note that the filter has a double peak with almost a 3 -dB valley or ripple at the specified peak response region. Of more significance is the rapid decrease in response beyond the 6 -dB points. The 3 -dB bandwidth is about 390 kHz. At 10 dB the acceptance window is about 500 kHz. My measurements do not agree as closely as I would have liked or expected with those given in muRata's published specifications for the SFE 10.7MA5 -A. The 3 -dB bandwidth, for example, is given as 280 ± 50 kHz. Though the ripple for this filter is not given, a graph published in muRata's literature suggests a ripple considerably less pronounced than the 3 dB I measured. its passage through the filter, with

-

--

-

-

-

A

10.7 -MHz Ceramic Oscillator. Quartz crystals are normalI've found that a ce-

ly used to regulate precision oscillators.

ramic filter will also work, but without nearly the precision quartz provides. Figure 6 shows a 10.7 -MHz ceramic oscillator. The circuit is virtually identical to the one in Fig. 3. The only exception is that Cl in Fig. 3 has been replaced by the ceramic filter.

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The variety of frequencies available with ceramic filters is much less than the vast number of quartz- crystal frequencies. SC/=

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of a 10.7 -MHz ceramic oscillator.

Nevertheless, the circuits in Figs. 3 and 6 suggest an interesting application: a matched radio-frequency oscillator and frequency- sensitive detector. The signal from the transmitter can be coupled directly or through the air via a fast-rise -time LED or by radio waves. (Additional circuitry will be required to implement this application.) Note that you will have to observe FCC regulations that apply to radio -frequency emissions. If you use a line -powered supply to operate the circuit, a nearby TV set may be subjected to severe video interference. The chief advantage of this application is the very low cost and compact size of the ceramic filter used in both the oscillator and receiver. The ceramic filter used to produce the plot in Fig. 5 oscillated at 10.71950 MHz when RI was 500 ohms. A second filter gave a frequency of 10.72105 MHz. This relatively minor difference is of little consequence since the oscillator can be tuned a few tens of kilohertz in either direction by changing the setting of R1.

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STATION

QUAL

4:00.4:15 a.m.

C900-0915

BBC

A

4:00-4:30 a.m. 4:00-5:30 p.m. 4:00-5:00 a.m.

0900-0930 0900-1030 0900 -1000 0915 -0945 0915 -1100

R. Japan. R. Australia

B

AFRTS, Los Angeles UN Radio BBC

A

0930 -1020 1000 -1030 1000-1100 1000 -1100 1000 -1100 1000 -1100 10001000 -1300 1000-1602 1010-1700 1030 -1130

V. of Germany V. of Vietnam R. Japan R. Korea

C C

All India Radio AFRTS, Los Angeles R. Australia R. Moscow (via Cuba) ABC, Perth V. of Nigeria Sri Lanka Br. Corp.

C

1058 -1300 1100 -1130 1100 -1130 1100-1130 1100 -1130 1100 -1156 1100 -1200 1100 -1200 1100 -1250 1100 -1300 1100 -1300 1100 -1330

CBC Northern Service R. Japan R. Finland V. of Vietnam R. Mogadishu R. RSA V. of Asia, Taiwan AFRTS, Los Angeles R. Pyongyang TWR- Bonaire

B-C

6:00-9:00 a.m. 6:00-10:00 a.m, 6:00-12:00 a.m. 6:15-6:30 a.m. 6:30-6:55 a.m. 6:30-7:30 a.m. 6:30-7:30 a.m. 7:00-7:15 a.m. 7:00-7:20 a.m.

1100 -1400

4VEH, Haiti VOA AFRTS, Los Angeles Vatican R. R. Nacional, Angola R. Korea R. Thailand V. of Kampuchean People CBC Southern Service

7:00-7:20 am. 7:00-7:30 a.m.

1200-1220 1200-1230

Vatican R.

7:00-7:30 a.m. 7:00-7:30 a.m.

1200 -1230 1200 -1230

R. Finland R. Norway

7:00-7:30 7:00-7:30 7:00-7:55 7:00-9:00

1200-1230 1200 -1230 1200 -1255 1200 -1400

R. Tashkent

7:00 a.m.-1:00 p.m. 7:00-7:35 a.m. 7:15-7:45 a.m. 7:30-7:55 a.m. 7:30-7:57 a.m. 7:30-8:00 a.m. 7:30-8:15 a.m. 7:30-8:25 a.m. 7:30-9:30 a.m. 7:30-10:51 a.m. 7:35-7:45 a.m. 8:00-8:45 a.m. 8:00-8:30 a.m. 8:00-8:50 a.m. 8:00-9:00 a.m. 8:00-10:57 a.m. 8:00-11:00 a.m. 8:00 a.m.-5:30 p.m.

1200-1800 1200-1235 1215-1245 1230-1255 1230-1257 1230-1300 1230-1315 1230-1325 1230-1430 1230-1551 1235-1245 1300-1345 1300-1330 1300-1350 1300-1400 1300-1557 1300-1600 1300-2230

R. R. R. R.

CBC Southern Service CBC Northern Service

B-C

8:15-8:45 8:30-9:00 8:30-9:00 8:30-9:00 8:30-9:20

a.m. a.m. a.m. a.m.

1315.1345 1330 -1400 1330 -1400 1330.1400

am.

1330 -1420

Swiss R. International R. Finland NYAB, Bhutan V. of Vietnam R. Nederland

D C C

4:15-4:45 a.m. 4:15-6:00 a.m.

4:30-5:20 s.m. 5:00-5:30 a.m. 5:00-6:00 a.m. 5:00-6:00 a.m. 5:00-6:00 a.m. 5:00-6:00 a.m. 5:00-fade out 5:00-8:00 a.m. 5:00-11:02 a.m. 5:10-12:00 a.m. 5:30-6:30 a.m.

5:58-8:00 a.m. 6:00-6:30 a.m. 6:00-6:30 a.m. 6:00-6:30 a.m. 6:00-6:30 a.m. 6:00-6:56 a.m. 6:00-7:00 a.m. 6:00-7:00 a.m. 6:00-7:50 a.m. 6:00-8:00 a.m.

6:00-8:00 am. 6:00-8:30 a.m.

a.m. a.m. a.m. a.m.

1100 -1500 1100-1700 1115-1130 1130 -1155 1130 -1230 1130 -1230 1200-1215 1200 -1220

R. Australia

BBC

B

B

C

C B

A B B

B C C

B B

C D C

C C C

A A

A-B

Kol Israel

HCJB, Ecuador R. Peking R. Moscow World Service

Peking Ulan Bator, Mongolia Japan Tirana Austrian R. R. Bangladesh V. of Germany R. Finland SLBC, Sri Lanka WYFR, Family Radio V. of Greece R. Japan R. Bucharest

WYFR, Family Radio R. Australia R. RSA

B B

FREQUENCIES, kHz'

The New ELF II "Beginners" Package

15070, 11955, 11750, 9640, 9510, 6195 15195,9505 15115 9590, 9530, 6030 15250, 9365, 9350 -558 (Sat) 17790, 17695, 15070, (21660 Sat. & Sun. and daily from 1030) 17780, 11850 12036, 10080 15235, 11875 9570 17875 11805, 9700, 9590, 9530, 6030 6045, 5995 9600 9610, 6140 15120 17850, 15120, 11835 (not all Eng.) 9625, 6065 (not all Eng.) 15195, 9635, 9505 21475, 15400 (Mon. -Sat.) 12036, 10080 9585 (irregular) 25790, 21535 5980 (Sun. 1030 -1040) 6030 9977, 9740 11815 (Sat & Sun. 1100 -1330) 17797, 9580 25650, 21710, 21660, 21550 11775, 11750, 9740, 9510, 6195 11835, 9770 11715, 9565 15430, 15330, 11805, 9700 21485, 17840 (not Sun.) 11955, 9535 (Mon: Fri.)(irreg). 15575, 9870 11905, 9655 11938, 9694 (vary) 17820, 15540, 11955 9650 (Mon. -Fri.) 21485, 17840 (not Sun.) 21760, 21625, 17630, 15605 15400, 21475 two of: 25730, 25615, 21735, 21730, 21725, 21760, 21555 (Sun.) 11785, 15460 26020, 15115, 11740 15520 15150, 15135, 12030, 11720, 9750, 9580 11600 12070, 6383 (not Sun.) 11875, 9675 11960, 9515 17880 21670, 15285 21600 21475, 15400 (Sun.) 15425, 9720 21545, 17785 (Sun. only) 17555, 15595, 11730 (Mon.-Sat) 11705, 11815, 9505 17850, 15250, 11940 11830 9770, 6080 25790, 21535, 15220 17820, 11955, 9579 (Sun.) 23440, 11720, 9625 (not all Eng.) 21570, 21520, 17850, 17830 21475, 15400 4595 (Wed. & Fri.) 12036, 10080 17605

Your own expandable micro-computer kit, 5 diagnostic analyzers plus circuit, programming, diagnostic manuals, even games you can play on TV. All only $139.95. Even if you don't know bits from bytes, now its easy and inexpensive to build your own micro-computer. learn how it works, program it. service it -even play games with it on your TV! It's here in the New ELF II "Beginners" Package, only from Netronics. Only $139.95. Here's the package: I. your own micro-computer, the famous ELF II ( featuring the RCA 1802 CMOS microprocessor) in kit form with step-by -step instructions on how to build it. Diagnostic Analysers including 2. your own Logic Probe. 3. Pulse Catcher. 4. 8 bit Test Registor, 5. Logic Analyzer. 6. Gate Arrays. 7. Non -Technical Manuals on how to use analyzers. how to get into the guts of the computer, what makes it tick. how to service it. 8. Sample Programs that teach you machine language programming plus how to correct or "debug" any programming mistakes. 9. TV games you can play. If your TV set has no video input. an optional converter (RF Modulator). is available. Then. once you've got this "Beginners" Package under your belt. keep on expanding your ELF I1 with additions like the Typewriter Key Board. added RAM, Full Basic Interpreter, Electric Mouth Talking Board, Color/Music. A /D -D /A Boards for Robot Controls and much, much more. We'll take you by the hand with the New ELF II "Beginners' Package. Only $139.95. Mail or phone in your order today and begin. Specifications. ELF II -.Beginners" Package The computer features an RCA CMOS 18028 tat microprocessor addressable to 64K bytes with DMA. interrupt. 18 Registers, ALU, 256 byte RAM expandable to 64K bytes. Professional. Hex keyboard. fully decoded so there's no need to waste memory with keyboard scanning circuits. built-in power regulator. 5 slot plugm expansion Bus less connectors 1. stable crystal clock for timing purposes and a double. sided. plated through PC Board plus RCA 1861 video IC to display any segment of memory on video monitor or TV screen along with the logic and support circuitry try you need to team ever/ eve one °Me RCA 1802's upabilmes. The diagnostic analyzers ad in understanding and trouble shooting your ELF 11. as well as other computer and microprocessor products.

Continental U.S.A. Credit Card Buyers Outside Connecticut

CALL TOLL FREE 800 -243 -7428 To Order From Connecticut or For Technical Assistance, Etc.,

Call (203) 354 -9375

NETRONICS R&D LTD. o 333

ph

PE-7

Litchfield Road, New Milford, CT 06776

Please send the items checked below: ELF II -`Beginners" Kit RF Modulator

$139.95 S 8.95

Plus53.00 for postage, handling and insurance (56.00 Canada) Connecticut Residents add sales tax

Total Enclosed

S

Cashier's Check /Money Order Master Charge (Bank No.

Personal Check

Visa Acct. No. Signature Print Name Address

Exp. Date

City State

JULY 1982

L

Zip

J

anazinc DCVICC1 -

PHASOR PAIN FIELD

P H

Patented and recently developed

in our labs is being tested by Gov't for riot control. Soon to come under weapons restrictions as an infernal machine. Easily handheld. Hazardous IF NOT USED WITH DISCRETION.

A

PPF -1

PLANS (sold for animal control)

PAIN FIELD GENERATOR S INVISIBLE rectional field moderately

-

$15.00

Produces a diintense pain to back of head up to 50' Cigarette pack size enclosure is easily hidden. IPG -3 PLANS $7.00 IPG-31( KIT & PLANS $44.50 IPG -30 (assembled for animal control) $59.50 PHASOR STUN/BURNING WAND Produces sufficient electrical energy capable of burning flesh. Intended as a personal defensé device. PSW -3 PLANS .. $8.00 PSW -3K KIT & PLANS $59.50 of

©

.

R

.

.

.

.

-

S

RUBY LASER RAY PISTOL

-

Intense visible red. burns. hazardous. with parts sources. RUBY PLANS (includes all part sources) $15.00 CARBON DIOXIDE LASER Generates 20-40 watts of continuous power capable of burning. cutting, hazardous. (with all part sources) $15.00 LASER RIFLE Produces 200 -3000 pulses of 30 watt optical energy. Portable and easily hand -held.

-

LRG -3 PLANS LRG -3K KIT PLANS

-

(minus diode) For the beginner, visible reo "optical non -hazardous.

POCKET LASER version ",

$10.00 5129.50

LHC -2K KIT & PLANS $5.00 $24.50 HIGH POWERED PORTABLE ENERGY SOURCE FOR LASERS AND MAGNETIC WEAPONS ExplodLHC -2

ing wires, shockwave, etc. Miniature size. HPS -1 PLANS. .. $8.00 HPS -1K KIT & PLANS. PARTICLE BEAM WEAPON PLANS

INFINITY XMTR

-

-

-

$49.50 $15.00

Uses telephone lines for selective home or office listening while away on business or vacation. INF -1 PLANS $15.00 SEE IN DARK Long range, total darkness. SD -4 PLANS $10.00 LONG RANGE WIRELESS MIKE Crystal clear quality

-

-

-

miniature

FBT -7 PLANS

.

.

.

$7.00

-

$34.50

FBT -7K PLANS & KIT

WIRELESS TELEPHONE TRANSMITTER range, automatic. VWPM -5 PLANS $10.00

VWPM -5K PLANS & KIT

Long

$34.50

Send for FREE catalog descripton of above plus hundreds more plans, kits and completed items. We accept MC or Visa or when ordering. send check or money order. We pay shipping charges on orders over $50.00, otherwise include 10% with remittance.

SEND TO:

SCIENTIFIC SYSTEMS BOX 716

DEPT. 01

AMHERST, NH 03031

SATELLITE

TV

ACCESSORIES DISCRETE 70MHZ PLL--- Replaces NE564 video demodulator. VCO guaranteed to 85 mhz. Wide bandwidth. No 'dropout' or 'birdies'. May be remotely tuned. (M82 -010K) Kit A & T (M82 -010T)

124.95 159.95

TUNEABLE AUDIO DEMODULATOR -- -Tunes from 5.4 to 8.2 mhz. Switchable 5 khz LP filter for Canadian birds. Tuning diodes included. Bare board (M81 -020B) $ 24.95 CANADIAN AUDIO DESCRAMBLER -- -Tune those 'chirping' sub -carriers hear what y u've beep missing. Bare board (R82 -010B) (R82 -OGOK) Kit A & T (R82 -010T)

in

and 24.95

59.95 94.95

LO -OHMS ADAPTOR - --Adapts normal VOM or DVM to measure from .001 ohm to 5 ohms using single 9 volt battery. Super simple calibration. Bare board (M82 -100ß) 24.95 (M82 -100K) Kit 39.95 A & T (M82 -100T) 59.95

MODEM ---Bell 103 (300 bps) compatible Answer /Originate modem. No acoustic coupler required. May be adjusted to Bell 202 (1200 bps) compatibility Bare board (R81 -LOOS) (R81 -100K) Kit A & T (R81 -100T) All

prices

1

include

24.95 69.95 99.95

complete

&

comprehensive documentation, postage, & handling. C.O.D. orders accepted. Call or write for catalog. DIGI -COM ENGINEERING, INC. BOX 1656 KODIAK, ALASKA 99615 907 -486 -5118 907- 486 -6215 OPEN 10 AM TO 86

8

8:30-9:30 a.m. 8:30-9:30 a.m. 8:30-10:00 a.m. 8:30-11:00 a.m.

1330 -1430

1330 -1430 1330 -1500 1330-1600

8:30 -11:00 a.m. 1330 -1600 8:30 &m.-fade 13308:30 a.m. -5:00 p.m. 1330 -2200

R. Korea V. of Turkey All India R.

C

C C

BBC R. R. Pl.

B-C

Malaysia Sabah Australia Moscow World Service

9720 15125 15335, 11810 25650, 21710, 21660, 21550 21470, 15400 (from 1430), 15070 5980. 4970

6060 11840

(via Cuba)

8:57-11:55 a.m. 9:00-9:30 a.m. 9:00-9:30 a.m.

1357-1655

9:00-9:30 a.m. 9:00-9:30 a.m. 9:00-9:45 a.m. 9:00-10:00 a.m. 9:00-10:00 a.m.

1400 -1430 1400 -1430 1400 -1445 1400 -1500 1400 -1500

V. Rev. Party, N. Korea

R.

Moscow World Service

9:00-10:00 9:00-10:00 9:00-12:30 9:30-10:25 9:30-10:30

1400 -1500 1400 -1500

R. V. R. R.

Malaysia Sarawak of Indonesia Australia Nederland

a.m. a.m. a.m. a.m. a.m.

1400 -1430 1400 -1430

1400.1730 1430 -1525 1430 -1530

V. of Philipines R. Sweden R. Norway

R.

Tashkent

BRT Belgium WYFR, Family Radio

HCJB,Ecuador

9:30-11:00 a.m. 9:30 a.m.-5:00 p.m. 9:35-10:20 a.m. 10:00-10:30 a.m. 10:00-10:45 a.m. 10:00-10:50 a.m. 10:00-11:00 a.m. 10:00-11:00 a.m. 10:00-11:00 a.m. 10:00-11:00 a.m.

1430-1600 1430-2200 1435-1520 1500-1530 1500-1545 1500-1550 1500-1600 1500 -1600 1500 -1600 1500-1600

Burma Br. Ser UN Radio R. Nepal V. of Asia, Taiwan R. Japan V. of Germany V. of Rev. Ethiopia V. of Nigeria BBC R. Moscow World Service

10:00-12:00 10:00-12:30 10:30-11:00 10:30-11:00 10:30-11:00 10:30-11:00 10:30-11:30 10:35-10:45 10:37-10:45 11:00-11:15 11:00-11:15

a.m. a.m. a.m. a.m. a.m. a.m. a.m. a.m. a.m. a.m. a.m.

1500-1700 1500 -1730 1530 -1600 1530 -1600 1530 -1600 1530 -1600 1530 -1630 1535 -1545 1537 -1545 1600 -1615 1600 -1615

WYFR, Family Radio BSHKJ, Jordan R. Afghanistan R. Yugoslavia Swiss R. International KTWR, Guam V. of Vietnam V. of Greece R. Canada International Vatican R. R. Pakistan

11:00-11:30 11:00-11:30 11:00-12:00 11:00-12:00

a.m. a.m. a.m. a.m.

1600-1630 1600 -1630 1600 -1700 1600 -1700

R. Norway R. Portugal R. Korea R. Moscow

9578 (Sun.- 1556)(not all Eng.) 17790 3 of: 26030, 25730, 25615 17840, 15125 (Sun.) 4557, 4109 15460, 11785 21810, 21525 (Mon. -Fri.) 15215 30750, 15150, 15135, 12030, 11900, 11720, 9750, 9580 7160, 4950 15200 or 15150, 11789 17795, 9710 21480, 17605, 11740 26020, 17890, 15115 (Sat. & Sun.I430-1600) 5985, 5040 21670, 15410 (when in session) 3425, 7105 or 9589 5980 (not Sun.) 11815, 9505

21600 9560 11770 (varies) 17830, 15260 (Sat., Sun.) 30750, 12050, 12010 11900, 11720, 9580

15365, 15215 9560 4775 or 6230 15415 21570, 17830, 15125 11945 15010,10040 17555, 15595, 11730 (Mon. -Fri.)

(17820 Mon. -Sat.), 15325

-11:05 a.m.

-1605

R.

Singapore

15120 17660, 17640, 15530 15175 21530 or 21475 (not Sun.) 11830, 9720 24020, 15240, 15150, 12050, 12030, 11900, 11720 21710, 17830, 15260 26040, 21660, 21485, 17870, (15250 from 1900) 15445, (15410 to 2200) 11940, 5052, 5010 (fade -in time

11:05.11:55 a.m.

1605.1655

R.

France International

varies) 25820, 21620, 21580, 21525, 1786(

11:15-11:50 a.m. 11:45-12:00 a.m. 11:45-12:45 pm. 12:00-12:30 p.m. 12:00-12:45 p.m. 12:00-1:00 p.m.

1615-1650 1645 -1700 1645-1745 1700.1730 1700 -1745 1700-1800

UAE Radio, Dubai

12:00-1:00 p.m. 12:00-1:00 p.m.

1700 -1800 1700 -1800

AFRTS, Los Angeles WYFR, Family Radio

12:30-3:00 p.m. 12:00-4:00 p.m. 12:00-5:00 p.m. 12:30-1:00 p.m. 12:45-3:00 p.m. 12:45-5:30 p.m. 1:00-3:00 p.m.

1700 -2000 1700 -2100 1700-2200 1730-1800 1745 -2000 1745 -2230 1800-1830

4VEH, Haiti BSK Saudi Arabia VOA HCJB, Ecuador BBC All India R. R. Canada International

1:00-1:30 p.m. 1:00-2:00 p.m. 1:00-2:00 p.m.

1800 -1830 1800-1900 1800-1900

R. Norway V. of Vietnam R. Moscow World

1:00-2:00 1:00-2:00 1:00-3:00 1:00-3:00 1:00-4:00 1:00-5:00

p.m. p.m.

1800 -1900 1800 -1900 1800 -2000 1800 -2000 1800 -2100 1800 -2200

WYFR, Family Radio V. of Nigeria R. Australia WRNO, New Orleans R. Kuwait AFRTS, Los Angeles

1:15-1:45 p.m.

1815-1845

Swiss R. International

1:15-2:00 p.m. 1:15-2:15 p.m. 1:30-1:37 p.m.

1815 -1900 1815 -1915 1830 -1837

BRT, Belgium

1:30-1:57 p.m. 1:30-2:00 p.m.

1830-1857 1830 -1900

Austrian Radio V. of Revolution, Guinea

2:00-2:30 p.m.

1900-1930

R.

2:00-2:30 2:00-2:30 2:00-2:45 2:00-3:00 2:00-3:00 2:00-3:00

p.m. p.m. p.m. p.m. p.m. p.m.

1900-1930 1900-1930 1900-1945 1900-2000 1900-2000 1900-2000

R. Afghanistan

2:30-3:30 p.m. 2:45-4:15 p.m. 3:00-3:30 p.m.

1930-2030 1945-2115 2000 -2030

V. of Iran

11:00 a.m.-12:45 p.m.1600 -1745 11:00 a.m. -6:00 p.m. 1600 -2300

p.m. p.m. p.m. p.m.

World Service

BBC VOA

R. R. R.

Canada International Pakistan Japan

BBC R. Moscow World Service

R.

Service

Bangladesh

UN Radio

Canada International

UN Radio R. Japan

HCJB, Ecuador WYFR, Family Radio R. Moscow World Service R. Free Grenada R. Norway

17730, 21486, 15565, 17875,

17850, 17720, 15315, 15300 21655, 17710 17820, 15325 15500, 11672f 9505, 11815 17695,21470 15455, 15425, 15240, 15150, 12050, 12030, 11960, 11900 15430, 15345, 15330, 11805 21615, 17845, 21510, 15440, 15365, 15215 11835, 9770 (Sun.) 11856 (varies) 17785, 15205 (15140 from 1830) 26020, 21477.5, 17790 15400, 15070 11620 17820, 15260 (Sat. & Sun. 1800 -1900) 23615, 21725, 17875,15175 (Sun.) 10040, 15010 17700, 15455, 15425, 15240 15150, 12050, 11960, 11900, 11700 21615, 15440, 15365 15120, 17800 17795, 9580, 9305 15420 (not all English) 11675 21570, 17765, 15430, 15345, 15330 21570 or 21585, 17850, 17830, 15415 17595 15308, 11767, (both vary)1 18782.5 -556, 15250, 21710, 15120 (Fri.) 17740, 15560 (Sun. from 1806) 15309 (varies) 9650 (Mon. Wed. and Fri.)(irregular) 21695, 17875, 15325 (Sat. & Sun. 1900 -2000) 15079 (varies), 9665 21710, 15250, 15120 (Fri.) 17755 26020, 21477.5, 17790 21615, 15440, 15365, 15215 17700, 15455, 15150, 12050, 11960 9022 15104 (time varies and irregular) 25615, 21705, 15205 -(Sun.)

PM PST

CIRCLE NO. 16 ON FREE INFORMATION CARD

POPULAR ELECTRONICS

3:00-3:30 p.m.

2000 -2030

R. Algiers

3:00-3:30 p.m.

2000-2030

R.

3:00 -3:30 p.m. 3:00 -4:00 p.m.

2000 -2030

Kol Israel R. Moscow World

3:00-4:00 3:00-4:15 3:00-6:00 3:10-4:40 3:15-3:30 3:30-4:15 3:30-4:20

p.m. p.m. p.m. p.m. p.m. p.m. p.m.

2000-2100

3:30-4:00 3:30-4:30 3:50-4:40 4:00-4:30 4:00-4:45 4:00-4:50 4:00-5:00 4:00-5:00

p.m. p.m. p.m. p.m. p.m. p.m. p.m. p.m.

2030-2100 2030-2130 2050-2140 2100-2130 2100-2145 2100-2150 2100-2200 2100-2200

V. V.

BRT, Belgium R. RSA V. of Nigeria R. Moscow World Service

C C

4:00-5:00 4:15-5:00 4:15-7:30 4:30-5:00

p.m. p.m. p.m. p.m.

2100-2200 2115-2200 2115-2430 2130-2200

WYFR, Family Radio BBC

A A

4:30-5:00 p.m. 4:30-5:00 p.m. 4:30-5:00 p.m. 4:31-5:00 p.m.

HCJB Ecuador

4:45-5:15 p.m. 5:00-5:30 a.m.

2130-2200 2130-2200 2130-2200 2131-2200 2145-2215 2200-2230

KGEI, San Francisco Swiss R. International R. Vilnius

C C

5:00-5:30 p.m. 5:00-5:30 p.m. 5:00-6:00 p.m.

2200-2230 2200-2230 2200-2300

R. Argentina R. Norway

WYFR, Family Radio

D C A

5:00 -6:00 p.m. 5:00-6:00 p.m.

CBC Radio V. of Turkey

A B

R. Jamahariyah, Libya BBC

B

5:00-6:00 p.m.

2200 -2300 2200 -2300 2200 -2300 2200 -2300

5:00-7:00 p.m.

2200 -2400

R. Moscow

A

5:00-7:00 p.m. 5:00-7:00 p.m. 5:00-11:30 p.m. 5:15-5:30 p.m.

2200-2400 2200-2400 2200-0430 2215-2230

CBC Southern Service AFRTS, Los Angeles

A

2000 -2100

2000-2115 2000-2300 2010-2140 2015-2030

2030-2115 2030-2120

C

Canada International Service

WYFR, Family Radio BBC WRNO, New Orleans R.

Habana Cuba

Sri Lanka Br. Corp. Int. Christ. Radio, Malta R. Nederland

R. R.

of Vietnam Turkey

Habana Cuba

Japan

A B A

A B

A A C C B

C C C C B B

Some o1: 25700, 21725, 21635 17745, 15370, 15215, 11810, 9610, 9510 21695, 17875, 17820, 15325, (Mon.-Fn.) 17645, 15585, 11640 17700, 15425, 15150, 15100, 12050, 11960 15215, 21525, 15440, 15365 21710, 15260, 15070, 12095, 17775 15175 15120, 15115, 11800 9510 21685, 17695, 17605, 15220, 9715 15010, 10040 9625 17750, 9770 17755 17595 (Mon.-Sat.)

11900,9585

7:00 -9:00 p.m. 7:00-10:00 p.m.

0000 -0200 0000 -0300

WRNO, New Orleans R.

Moscow

7:00-12:00 p.m. 7:00 p.m.-4:00 a.m. 7:05-8:55 p.m. 7:30-8:00 p.m.

0000-0500 0000-0900 0005-0155 0030-0100

R.

Moscow (via Cuba)

7:30-8:00 7:30-8:00 7:30-8:15 7:30-8:30 7:30-9:30 7:30-9:30

0030-0100 0030-0100 0030-0115 0030-0130 0030-0230 0030-0230

R.

HCJB, Ecuador SLBC, Sri Lanka BBC

A C A

0035-0230 0100-0115 0100-0120 0100-0125 0100-0130 0100-0130 0100-0130 0100-0130

HCJB, Ecuador RAI, Italy Kol Israel R. Japan

B B B A C

R. Argentina R Mexico La Voz de la Mosquitia,

C C C

15120, 17800 21530, 17720, 15425, 15240, 15100, 12050, 11960, 11750 17845, 15440, 15380, 15365 21710, 15260, 15070 15045 (time varies)(irregular) 17820, 15150, 11945, (17875, 15325 Sat. & Sun. only) 21477.5, 26020, 17790t, 15295t 15315, 11860, 11850 9745 15280 21585, 17830, 17850, 15305 17870, 17835, 15100, 11790 11770 11710 (Mon.-Sat.) 17895, 15345, 15305 (Sun. only) 17845, 15440, 11805, 15365, 15380 17875, 15325 (Mon.-Fri.) 9560, 7155 11815 21710, 15420, 15260, 15070, 11750, 9510, 6175, 6120, 5975 21530, 17720, 15180, 15140, 12060, 12050, 11960, 11900, 11739, 9765, 9710, 9685, 9610, 9755, 5960 (not all English) 21570, 17765, 15430, 15330 21460, 17740 17755, 15235, 15195 (11760 via Portugal) 17785, 15305 (Fri.) 9620 21710, 17630, 15585, 11640 11955, 9535 (Mon.-Fri.)(Irreg.) 15430 (Sun.; time varies) 15330, 15110 9625, 6195 (not all English) 17755, 15235, 15195 11705, 15380 11835, 9770 15365, 17845, 15380 15430 (Thurs.; time vanes) 15420, 15260, 15070, 11910, 9510, 9410, 7325, 6175, 6120, 5975 9977 11855 6090 (time vanes) 17870, 17835, 15100, 11790, 11770 12036, 10080 17825, 21610 9750, 7065 9755, 5960 11640, 17630, 15585 17840, 15205, 15160 (Mon. only) 11970, 9730 17855, 17680 17845, 11720 15110, 15330 21570, 15430, 15330, 11790 17730, 15205, 11740, 9650, 6130, 5995 11965 17720, 12060, 11960, 9685 9610 9600 6055 (when in session) 11880, 9630 17710, 15220, 11910, 9835, 9585 (Wed. & Sat.) 6055 4875 (Mon. only) 11695, 15360 15175 15425 15260, 15070, 11835, 11750 9510, 9410, 7325, 6175 6120, 5975 17875, 15155, 9745 11845, 9605, 6015 11800, 9575 15585, 11640, 9815 17755, 17810 11710, 9690 (not Mon.) 15430 (Sun.) 4910

Honduras R Canada International R. Budapest

A

9755, 5960

B

17710, 15220, 11910, 9835, 9585 (not Mon.)

5:00 -6:00 p.m.

5:15-5:30 p.m. 2215-2230 5:15-5:30 p.m. 2215-2230 5:30-6:00 p.m. 2230-2300 5:30-6:00 p.m. 2230-2300 5:30-6:25 p.m. 2230-2325 5:30-6:30 p.m. 2230-2330 5:30 p.m.-12:09 am 2230-0509 6:00-6:30 p.m. 2300-2330 6:00-6:30 p.m. 2300-2330 6:00-7:00 p.m. 2300-2400 6:00-7:00 p.m. 2300-2400 6:00-7:00 p.m. 2300-2400 6:00-7:30 p.m. 2300-2430

6:00-7:50 6:00-8:00 6:00-8:45 6:30-7:00

p.m. p.m. p.m. p.m.

6:30-7:00 6:45-7:45 7:00-7:25 7:00-7:30 7:00-7:30

p.m. p.m. p.m. p.m. p.m. 7:00-7:30 p.m.

7:00-7:45 7:00-7:55 7:00-8:00 7:00-8:00 7:00-8:00 7:00-9:00

p.m. p.m. p.m. p.m. p.m. p.m.

p.m. p.m.

p.m. p.m. p.m. p.m.

7:35-9:35 p.m.

8:00-8:15 8:00-8:20 8:00-8:25 8:00-8:30 8:00-8:30

p.m. p.m. p.m. p.m. p.m.

8:00-8:30 p.m. 8:00-8:30 p.m.

8:00-8:30 p.m. 8:00-8:30 p.m.

2300-2450 2300-0100 2300-0145 2330-2400

2330-2400 2345-2445 0000-0025 0000-0030 0000-0030 0000-0030 0000-0045 0000-0055 0000-0100 0000-0100 0000-0100 0000-0200

0100-0130 0100-0130

R. R.

R. R.

Free Grenada Canada International Sofia Baghdad

VOA R.

Japan

B

A C B

C

B

A

A A C

UN Radio R. Yugoslavia Kol Israel

A C

R. Nacional, Angola R. Mexico R. Sofia

D

CBC Northern Service R. Japan

Sweden 4VEH, Haiti

A B

B C C

R.

C

WYFR, Family Radio R. Mexico BBC

B A B A

R. Pyongyang

C

WRNO, New Orleans

A

R. Luxembourg R. Kiev

C

of Vietnam R. Japan R. Tirana R. Canada International

C C

V.

Kol Israel R. Norway R. Berlin International R. Peking WYFR, Family Radio R. Sofia

A

B

A A C

C B A B

AFRTS, Los Angeles

A

VOA

A A A

UN Radio

Spanish Foreign R. R. Budapest

Prague

La Cruz del Sur, Bolivia BRT, Belgium

Vatican R.

A A B

B C D B

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Learning and having fun with electronics is easy, once you understand the basics. To help you get started, the Editors of Popular Electronics put together the all -new INVITATION TO ELECTRONICS -the guide that explains basic electronics in clear layman's language. INVITATION TO ELECTRONICS covers all kinds of electronic gear and procedures, including: Television and video, from disc and tape players to satellite and projection TV. Audio gear, including amps and tuners, turntables, speakers, tape decks, photo cartridges and more. Personal computers: how they work, what they can do, and where you can best use them. Radio communication including ham radio, CB and marine band. Understanding wiring and circuits, diagrams and schematics. Troubleshooting techniques and how to use test equipment. Education and careers in electronics. You'll also learn what's new and what's coming in the future, how to find your way around electronics terminology, and much more!

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8:00.8:50 p.m. 8:00-8:55 p.m. 8:00-8:55 p.m. 8:00-9:00 p.m. 8:00-9:00 p.m. 8:00-9:00 p.m. 8:00-9:00 p.m. 8:00-10:00 p.m. 8:00-10:30 p.m. 8:00-11:50 p.m.

0100-0150

V.

of Germany

A

8:20 p.m.-12:10 8:30-8:40 p.m. 8:30-8:57 p.m. 8:30-8:55 p.m. 8:30-9:15 p.m. 8:30-9:30 p.m. 8:45-9:15 p.m. 9:00-9:25 p.m. 9:00-9:30 p.m.

0100-0155 0100-0155 0100-0200 0100-0200 0100-0200 0100-0200 0100-0300 0100-0330 0100-0450 a.m.0120-0510 0130-0140 0130-0157 0130-0155 0130-0215 0130-0230 0145-0215 0200-0225 0200-0230

9:00-9:30 p.m. 9:00-9:30 p.m. 9:00-9:30 p.m.

0200 -0230 0200 -0230 0200 -0230

R. Norway R. Kiev R. Budapest

9:00-9:40 p.m.

0200-0240

R.

Polonia

B

9:00-9:50 p.m. 9:00-9:55 p.m.

0200-0250 0200-0255

R. R.

RSA

C C

9:00-9:55 p.m.

0200-0255 0200-0300

R. Peking R. Korea

B C

0200 -0300 0200 -0300 0200 -0300 0200 -0330 0200-0330 0200 -0400

R. Nacional, Brazil

A A A

9:00-11:30 p.m. 9:30-9:45 p.m. 9:30-9:45 p.m.

0200-0430 0230-0245 0230-0245

AFRTS, Los Angeles R. Pakistan UN Radio

A C A

9:30-9:55 p.m. 9:30-10:00 p.m. 9:30-10:00 p.m. 9:30-10:15 p.m. 9:30-10:25 p.m. 9:30-10:30 p.m.

0230-0255 0230 -0300 0230 -0300 0230 -0315 0230 -0325 0230 -0330

R. Tirana R. Lebanon R. Sweden R. Berlin International R. Nederland

B

9:30-12:00 p.m. 9:51-9:58 p.m.

0230-0500 0251-0258 0300-0315

HCJB Ecuador V. of Yerevan

10:00-10:15 p.m.

R. Budapest

B B

10:00-10:25 p.m.

0300-0325

R. Polonia

B

Japan Canada International Portugal Australia of Free China Prague Peking TIFC Costa Rica R. Baghdad WYFR, Family Radio V. of Free China R. Uganda R. RSA R. Cultural, Guatemala HRVC, Honduras AWR, Guatemala WRNO, New Orleans VOA R. One, Zimbabwe R. Tirana

C

U.A.E. Radio, Dubai

B C

9:00-10:00 9:00-10:00 9:00-10:00 9:00-10:00 9:00-10:30 9:00-10:30 9:00-11:00

p.m. p.m. p.m. p.m. p.m. p.m. p.m.

R. Prague R. Peking

B B

V. of Free China R. Zinica, Nicaragua

C C

AFRTS, Los Angeles WYFR, Family Radio WRNO, New Orleasn R. Australia R. Habana Cuba R. Belize V. of Greece Austrian Radio R. Tirana R. Berlin International R. Japan Swiss R. International

A

Kol Israel R. Canada International

Bucharest

WYFR, Family Radio V. of Free China, Taiwan R. Australia R. Cairo VOA

B

A B B

C B B

B C C

A A A B A B

B B

A

15105, 11865, 9590, 9565, 9545, 6145, 6085, 6040 11990, 9740, 9540, 7345, 5930 17855, 17680 17890, 15345, 11825 6120.4 (Tue.-Sat.) 21570, 15430, 15330, 11790 9715, 11720 9685

21740 11930, 11725 3285, 834 15595, 11730, 9865 (not Sunday) 9770, 5945 9750, 7120 11975, 9730 21640, 17825, 21610, 15195 15305, 11715, 9725, 6135 11585, 11640, 9815 9755, 5960 (Sat. & Sun. also 15190, 11845, 9535) 15165, 11870, 11740 (Mon. only) 11790, 11770, 9665 17710, 15220, 11910, 9835, 9585 15120, 11815, 9525, 7270, 7145, 6135, 6095 (length varies) 11900, 9580, 5980 15380, 11940, 11840, 11725, 9570, 5990 17680 15575, 11810 17830, 15290 11720, 9715 11740 (via WYFR) 17795 12000, 9475 17730, 15205, 9650, 6130,

5995,1580

BBC

10:00-10:30 p.m. 0300-0330 10:00-10:30 p.m. 0300-0330 10:00-10:30 p.m. 0300-0330 10:00-10:30 p.m. 0300-0330 10:00-10:50 p.m. 0300.0350 10:00-10:55 p.m. 0300-0355 10:00-10:55 p.m. 0300-0355 10:00-11:00 p.m. 0300-0400 10:00-11:00 p.m. 0300-0400 10:00-11:00 p.m. 0300-0400 10:00-11:00 p.m. 0300-0400 10:00-11:00 p.m. 0300-0400 10:00-11:26 p.m. 0300-0426 10:00-11:30 p.m. 0300-0430 10:00-12:00 p.m. 0300-0500 10:00-12:00 p.m. 0300-0500 10:00 p.m.-1:00 a.m.0300-0600 10:00 p.m.-2:30 a.m.0300-0730 10:25 p.m.-fade 032510:30-10:55 p.m. 0330-0355 10:30-11:23 p.m. 0330-0423 10:30-10:57 p.m. 0330-0357 10:30-11:00 p.m. 0330-0400

R. R. R. R. V. R. R.

10:30-11:00 p.m. 0330-0400 10:30-11:45 p.m. 0330-0445 10:30 p.m.-1:00 a.m.0330-0600 10:40-10:47 p.m. 0340-0347 10:50-11:10 p.m. 0350-0410 11:00-11:30 p.m. 0400-0430

R.

Austrian Radio R. Australia Mexico BBC R. Habana Cuba V. of Greece RAI, Italy R.

Bucharest

11:00-11:30 p.m.

0400-0430

R. Norway

11:00-11:30 11:00-11:55 11:00-12:00 11:00-12:00

0400 -0430 0400-0455 0400-0500 0400-0500

R. R. R. R.

11:00-12:00 p.m. 0400-0500 11:00-12:00 p.m. 0400-0500 11:00 p.m.-2:25 a.m.0400-0725 11:00 p.m.-3:00 a.m.0400-0800 11:05-11:50 p.m. 0405-0450 11:30-11:57 p.m. 0430-0457 11:30-12:00 p.m. 0430-0500 11:30 p.m.-1:00 a.m.0430-0600 11:45-12:00 p.m. 0445-0500

R.

11:45 p.m.-12:45 am.0445-0545 11:55 p.m.-3:00 a.m.0455-0800 12:00-12:15 a.m. 0500-0515 12:00-12:30 a.m. 0500-0530 12:00-12:50 a.m. 0500-0550

BBC

12:00-1:00 a.m.

12:00-1:00 a.m.

p.m. p.m. p.m. p.m.

Mozambique Peking Sofia Australia

Moscow World Service WYFR, Family Radio TWR, Bonaire R. Moscow FEBA, Seychelles Austrian R. Swiss R. International AFRTS, Los Angeles Vatican R. V.

of Nigeria

C

8 B

A A A

A B

C C B B

C D

A A B B

B B

C

A A C B

B

C C

A B B

C C C B

C B

A A A A C B B

A C A B

Kol Israel

B

R. Japan V. of Germany

C

0500-0600

R. Australia

C

0500-0600

V.

of Nigeria

A

C

11790, 6030

17840,21595 15240, 6035, 15752-SSB, 10869 -SSB (Sal.) 9750, 7120 11806t (time varies) 11705, 15420, 17840-SSB 11970, 11890, 11840 9590, 6165 (Mon. 0230-0320) 11750, 9510, 9410, 7325, 6175, 6120, 5975 9745, 15155 17870, 15100 17710, 15220, 11910, 9835, 9585, (Wed. & Sat; Mon. 0300-0330) 15120, 11815, 9525, 7270, 7145, 6135, 6095 (length varies) 17755, 17810 11940, 11845, 9755, 9535, 5960 11925 17750 (Fri.) 15345, 11825, 17800 11990, 9740, 9540, 7345, 5930 15120, 17680, 17855 5055, (Mon. 0235-0435) 21585, 15400, 11935 9715, 9660 5985 (via WYFR) 15325 (irregular) 11900, 9585, 7270, 5980 3300 (Mon. 0030-0430) 4820 5980 6155 (not all English) 15240, 9670, 6040, 6035, 5995 3396 (exc. Sun.) 7300, 6200 17775, 15320, (length varies) 9770, 5945 21680, 17890, 17870, 17795, 17725 15430 (Mon.) 15070, 9410, 6175, 5975 11760, 11725 15595, 11730, 9865 (not Sun.) 21560, 17795, 15330, 11905 15380, 11940, 11725, 9570, 5990 17840, 15165, 15125, 11895, 11870 (Mon.) 4865, 3265 (vary) 17680, 15120 117501 21680, 21650, 21525, 17870, 17795, 17755, 17725 15320, 15240, 15160 9665, 9610 9715, 9660, 6070 9755, 800 12050, 9580

11810t, 15200t 12015 11715, 9725 11790, 6030 6208, 9645 15070, 9510, 9410, 6175, 5975 11770 21760, 15105, 11640, 9815 17810, 15325 11905, 11705, 9690, 9650, 9545, 5960 21680, 17870, 17725, 15240, 15160 15120

J

88

POPULAR ELECTRONICS

Popu 12:00-1:00 a.m. 12:00-1:00 a.m. 12:00-2:00 a.m. 12:00-3:00 a.m. 12:00-3:00 a.m. 12:30-12:40 p.m. 12:30-1:00 a.m. 12:30-fade 12:30-1:25 am. 12:30-1:30 a.m. 12:35-1:30 a.m. 12:45-1:30 a.m. 12:45-2:30 a.m.

0500-0600 0500-0600 0500-0700 0500-0800 0500-0800 0530-0540 0530-0600 05300530-0625 0530-0630 0530-0630 0545-0630 0545-0730

WFYR, Family Radio R. Moscow World Service

12:55 -3:55 a.m. 1:00-1:30 a.m. 1:00-1:30 a.m.

0555 -0855 0600 -0630 0600 -0630

V. of Malaysia R. Norway V. of Germany

1:00-1:30 am.

0600 -0630

R.

1:00-2:00 a.m. 1:00-2:30 am. 1:00-2:30 a.m. 1:00-3:00 &m. 1:00-4:00 &m.

0600-0700 0600-0730 0600-0730 0600-0800 0600-0900

AFRTS, Los Angeles HCJB, Ecuador R. Kiribati WRNO, New Orleans R. Cook Islands

1:15 -1:30 a.m.

0615-0630

R. Canada International

1:25 -3:00 a.m. 1:30 -2:00 a.m.

0625 -0800 0630 -0700

TWR, Monte Carlo

1:30-2:00 a.m.

0630-0700 0630-0730 0630-0800 0645-0700

Radio Polonia

9675, 7270

R. RSA R. Habana Cuba R. Canada International

0645-0700 0657-0955 0700-0715 0700-0720 0700-0730 0700-0800 0700-0800 0700-0800 0700-0800 0700-0900

UN Radio

0700-1100 0707-0715 0730-0825 0730-0900

HCJB Ecuador UN Radio R. Nederland BBC GBC-2, Guyana

21535, 17780, 15220 9525 11960, 11825, 11775, 9780, 9730, 7155, 6140 (Mon -Fri) 15125, 11740 (Sat.) 9578 (not all English) 17810, 15325, (15239 via Portugal) 21480, 15580, 11720, 9895 15305, 9580, 9535, 6165 9670 (Sat.) 15120 11830 9840 21680, 11729, 15115 9570 11925, 6130 (9745 at 0700-1030) 15125, 11740 (Sat.) 9770, 9715 15070, 11955, 9640, 9510 5950 9545 or 5020 (not all Eng.) 4890, 3925 (not all Eng.)

1:30-2:30 a.m. 1:30-3:00 a.m. 1:45-2:00 &m. 1:45-2:00 &m. 1:57-4:55 am.

2:00-2:15 2:00-2:20 2:00-2:30 2:00-3:00 2:00-3:00 2:00-3:00 2:00-3:00 2:00-4:00

&m. &m.

am. &m. a.m. a.m. a.m. a.m.

2:00-6:00 a.m.

2:07-2:15 &m. 2:30-3:25 a.m. 2:30-4:00 a.m. 2:30 a.m.-fade 2:30-6:30 a.m. 2:30-9:00 a.m. 2:30-9:02 a.m. 2:37-2:45 a.m.

0730-

0730-1130 0730-1400 0730-1402 0737-0745

HCJB Ecuador R. Kuwait R. Nigeria, Kaduna R. Garoua, Cameroon R. Portugal R. Ghana R. Nederland Spanish Foreign R. R. Korea R. Berlin International BBC

3366, 4915 9715, 6185 (Mon. 0530 -0620) 11880, 9630 15575, 11810, 9870 11890 15070, 11955, 11860, 9840 9510, 9410, 7150, 6175 15295, 12350, 9750 21580, 15175 (Mon.) 17875, 15275, 11905, 11765, 9700 21680, 21525, 17870, 17795, 17755, 17725, 15240, 15180 11790, 6030 11810 16433-SSB (not all English) 9550 (Sun.) (not all English) 11760 or 9695 or 5045 (not all English) 11960, 11825, 11775, 9760, 9730, 7155, 6140 (Mon-Fri) 9495 (Sunday 0625-0900) 21680, 17870, 17725, 15240, 15160, 15115, 11820

Australia

R. Australia

V. of Philipines R. Japan R. Nederland

Swiss Radio Int. Xandir Malta V. of Nigeria

ELWA, Liberia V. of Vietnam R. Australia

Solomon Ist. Broadcasting NBC, Papua New Guinea

ABC Melbourne UN Radio

9705, 9660, 6070 17880, 12010, 11735, 9530 11915, 9745, 6095 15345 4770 (not all Eng.) 5010 9575, 6100

0800-0815

KTWR, Guam R. Norway UN Radio

9680 17815, 15195, 15125, 11740 (Sat.) 11840 11895, 11870 (Sun.) 17860, 15235, 15125, 11740

0800 -1000 0815 -0830 0830 -0900 0830 -0925 0830-1000 24 Hours

WRNO, New Orleans R. Vanuatu AWR Portugal R. Nederland FEBC, Phillippines CFRX, Toronto

6115 (Sun. only; not all English) 7260, 3945 9760 or 9665 (Sun.) 9715 11890 6070

2:45-4:30 &m. 3:00-3:30 &m. 3:00-3:15 a.m.

0745-0930 0800-0830

3:00 -5:00 3:15 -3:30 3:30 -4:00 3:30 -4:25 3:30 -5:00 24 Hours

(Sat) a.m. a.m. a.m. a.m. a.m.

ExplanatoryNotes. 1. Times in first column are CDT. For ADT add 2 hours; EDT add 1 hour; MDT subtract hour; DDT subtract 2 hours; Days of week are in GMT. 2. Quality. A- Strong signal and very reliable reception. B- regular reception. C-occasional reception under favorable conditions. D-- rarely audible. These ratings are for locations in the central USA. European and African stations are in general, more reliably received in eastern North America. Asian and Pacific stations are more reliably received in western North America. North American stations are received well except in areas too close to the transmittersite. 3. The information in the listing is correct to press time. However, frequencies and schedules are constantly changing. Listen to "SWL Digest" on R. Canada International for late changes, Saturday at 2135; Sunday at 1930; GMT Mondays at 0106 and 0306. 1

4.

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9

59

11

13 12

15 16 17 14

48,49 47 18

19

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A Fully Adjustable Pulse Generator

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THE 558

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Get A GNOME

the original micro -synthesizer Every day more people discover that PAIA's GNOME is the most versatile, cost effective special effects device on the market today. John Simonton's time- proven design provides two envelope generators, VCA, VCO and VCF in a low cost, easy to use package. Use alone with it's built in ribbon controller or modify to use with guitar, electronic piano, polytonic keyboards, etc. The perfect introduction to electronic music and best of all, the Gnome is only $69.95 in easy to assemble kit form. Is it any wonder why we've sold thousands?

is a quad timer chip with many useful applications. The diagram shows one of the best, a highly versatile, square -pulse generator with fully adjustable pulse rate and pulse duration. The circuit is adapted from Exar's XR- 558/559 data sheet. In operation, the two timers shown are cross -connected so that the output of one timer is directly coupled to the trigger input of the other timer. When the timing cycle of the first timer is complete, the second timer is triggered. When its cycle is complete, the first timer is triggered. The result of this feedback cycle is an astable multi vibrator. The significance of this multivibrator circuit is that the RC time constant of each timer section is independently adjustable. This means that both the pulse rate and duration are independently controllable. Resistor R1 controls the frequency of the pulses and R2 controls their duration. Notice that the circuit provides complementary outputs. The pulse rate of the circuit is given by the reciprocal of (RICI) + (R2C2). The minimum practical pulse duration is on the order of a microsecond, and the maximum pulse rate is about 100 kHz. The pulses remain very square until their duration falls to a few microseconds. Their amplitude can be altered by varying the power -supply voltage. The oscillation frequency of each timer in a 558 can be altered by changing the circuit's control voltage. The 558 has a single control voltage pin which is common to all four timers. However, the duty cycle of the circuit is unaffected by application of a control voltage. This means the circuit can be operated as a variable -frequency oscillator having a fixed duty cycle.

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tion for the plastic -package 58 is 625 mW. If the circuit is operated at 10 V, 100 mA per output would give a total dissipation of 4 W (from Ohm's law, 10 V X 0.1 A = 1 W per timer). Therefore, the current delivered to each output would have to be reduced or external buffering would be required. If each output is required to deliver only 10 mA, then the total power dissipation would be 4 X 10 V X 0.01 A = 0.4 W, well within the 625 mW maximum. Incidentally, this circuit will cease oscillation if an attempt is made to operate it beyond its minimum pulse duration or maximum frequency. Should this occur, adjust the appropriate pot (or capacitor if you prefer) and momentarily disconnect the power to restart the circuit. If the circuit fails to operate when power is first applied, it is possible both RC time constants are out of range and require adjustment to bring the circuit within its operating limits. O

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name address Lofty

Driving External Circuits. The output stage of each timer in the 558 is a normally low, open -collector, npn transistor that can sink up to 100 mA. This means the circuit can directly drive an LED, a small relay, or even a small speaker for audio effects. However, though each timer can sink up to 100 mA, the power dissipation rating of the timer's package limits the maximum current per timer if all four are in use. For example, the maximum dissipa-

T

C/ DIRECT INQUIRIES TO

To

You can add a fixed- duty-cycle frequency control by connecting the rotor of a 10- kilohm potentiometer to pin 4 of the 558. Connect the stator terminals of the pot to Vcc and ground, respectively. Adjust the pot to alter the frequency.

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7494 7495

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7440 7442

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7445 7446 7447 7448 7450 7451 7453 7454 7460 7470 7472 7473 7474 7475 7476

7480

7496 7497 74100

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74111

1.00 .30 .45 .45 .55

74116

1.55

74120

1.20 .29 .45

74107

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74121 74122 74123 74125 74126 74128 74132

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74142

2.95

74143 74145 74147

2.95 .60 1.75 1.20 1.35 .65 .65 .55

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74159 74160 74161 74162

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74190 74191 74192 74193 74194 74195 74196 74197 74198 74199 74221

74246 74247 74248 74249 74251 74259 74265 74273 74276 74279 74283 74284 74285 74290 74293 74298 74351

74365 74366

74367 74368 74376 74390 74393 74425 74426 74490

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74C04 74C08 74C10 74C14 74C20 74C30 74C32 74C42 74C48 74C73 74C74 74C76 74C83 74C85 74C86 74C89 74C90 74C93 74C95 74C107 74C150

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74C154 74C157 74C160 74C161 74C162 74C163 74C164 74C165 74C173 74C174 74C175 74C192 74C193 74C195 74C200 74C221 74C373 74C374 74C901 74C902 74C903 74C905 74C906 74C907 74C908 74C909 74C910

3.25 1.75 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.25 2.25 2.25 2.25 2.25 5.75 2.25 2.75 2.75 .80 .85 .85 10.95 .95 1.00 2.00 2.75 9.95 10.00 10.00 1.95 2.00 2.75 17.95 15.95 5.59 5.95 6.75 7.95 7.95 7.95 19.95 19.95

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4012 4013 4014 4015 4016 4017 4018

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2.95 3.95 14.95 2.95 1.89 4.90 4.25 14.95 8.95

198

74S280 74S287 74S288 74S289

2.90 4.75 4.45 6.98

74S301

6.95

74S373 74S374

3.45 3.45

74S381

7.95

74S387 74S412 74S471 74S472 74S474 74S482 74S570 74S571

5.75 2.98 9.95 16.85 17.85 15.60 7.80 7.80

1.39 1.49 1.83 19.95 19.95

'6 r6

Upgrade your 48K Apple* lI to full 64K. Fully software and hardware compatible with Apple language card and microsoft Z80 card. Eliminates the need for Applesoft or Integer Basic ROM card when used

conjunction with DOS 3.3 Allows you to run Apple Fortran or

in

Pascal.

Available as bare board kit, or completed and tested board.

BARE BOARD KIT ASSEMBLED & TESTED

18

I

JDR MICRODEVICES, INC. P12111

74S161

1.24 .98 .69 1.48 1.08 1.25 1.45 3.75 3.98 1.90 7.45 1.19 1.45 2.85

3.75 4.65 5.44

.95 .85 .95 .95

80C95 80C96 80C97 80C98

3" .3" .3" .2"

2.77

74S163 74S168 74S169 74S174 74S175 74S181 74S182 74S188 74S189 745194 74S195 74S196 74S197 74S201 74S225 74S240 74S257 74S258 74S260 74S274 74S275

RAM CARD

.95 .95 1.95

80007

1.44 1.59 1.98 1.50

16K APPLE*

2.70

4582 4584 4584 4702 4724

2.39

MX-80 MX -80 /FT MX -100

1.95 1.95 1.95

4581

74S85 74S86 74S112 745113 74S114 74S124 74S132 74S133 74S134 74S135 74S138 74S139 74S140 74S241 74S244 74S251 74S253 745157 74S158

r EPSON PRINTERS

.95 .95 .95 2.49 1.95 12.95 12.95 11.95 12.95 4.95 .95 .65 1.95 .95 .95 .95 1.25 2.25 1.55 1.25 1.25 1.25 1.25 1.25 1.95 1.25 .95

4532 4538 4539 4543 4555 4556

.78 .79 1.25 .69

74S65

.30

4531

.44

L

.30

4512 4514 4515 4516 4518 4519 4520 4522 4526 4527 4528

.98

1.87 1.68

74551 74S64

.75 .40 .35 .35 .30 .30 .30 .30 .95 .30

4511

.88 .70 .68 .98 .48

74S15 74S20 74S22 74S30 74S32 74S37 74S38 74S40

.85

4072 4073 4075 4076 4078 4081 4082 4085 4086 4093 4098 4099 14409 14410 14411 14412 14419 4502 4503 4508 4510

.44 .48 .48 .79 .79 .48 .98 .69

74S05 74S08 74S09 74S10

.95 1.25 .75 .85 .85 .95 .95 .55 .55 .95 .95 1.45

VOLUME QUOTES 74S00 SERIES

74SO4

2.95

4071

US FOR

74S00 74S02 74S03

LED LAMPS

LED DISPLAYS 1.29 .99

L

2.25

4011

J

r

74C151

1.75 1.20

.45 .95 .95 1.15 .35 .75 .35 1.65 .65 .80 .95 .45

4021

1.00 5.75

74C912 74C914 74C915 74C918 74C920 74C921 74C922 74C923 74C925 74C926 74C927 74C928 74C929 74C930 4000 4001 4002 4006 4007 4008 4009 4010

3.75 3.75 .95 .75 .85 2.25 .65 .65 .65 .65 2.20 1.75 1.35 3.15 .85 2.55

4019 4020 4022 4023 4024 4025 4026 4027 4028 4029 4030 4034 4035 4040 4041 4042 4043 4044 4046 4047 4049 4050

74C911

2.00

.35 .35 .35 .35 .35 1.50 .35 .35 .50

(;AEI.

r

CMOS 74C00

7400

1:E1)!

1224 S. Bascom Avenue San Jose, CA 95128 800 -662 -6279 (CA) 800 -538 -5000 Telex 171 -110 (408) 995 -5430

Apple

$

40.00 89.95

109.95

is a trademark of APPLE COMPUTER INC.

HOURS: Mon.

-

Fri., 9 to 5: Sat.

11

to

3

VISIT OUR RETAIL STORE! For shipping include $2.00 for UPS Ground, $3 00 for UPS Blue Label Air. $10.00 minimum order. Bay Area residents add 61/2°ó sales tax. California residents add 6% sales tax. We reserve the right to limit quantities and substitute manufacturer. Prices subject to change without notice. Send SASE for complete list. TERMS:

ALL MERCHANDISE.

100`)i

GEAR

CALL

*

SELECTABLE 40 or 80 CHARACTERS PER LINE 15 MHZ BANDWIDTH

*

At JDR Microdevices. Inc 100% customer satisfac'ion is our goal! Our first priority ,,stomers receive our world famous JDR service: make sure that all of

MOD -L ZVM -121 P -31 Green phosphor

12"

GUARANTEED LOWEST PRICES!

FRIENDLY STAFF!

I

...

a pleasant experience.

To speed your order on its way n

one day with superb accuracy.

would like to take this opportunity to thank all of our customers for making JDR one of the fastest growing electronic firms in the world!

*

RE SIDE N "`

A

copy of

rh,

Jeffery

this policy is

NTHANA ss SD SOFT \' /ABASH SS SD SOFT VERBATIM SS SD SOFT VERBATIM 'O SECTION HARD A

available upon -equest.

OSBORNEIMC GRAW -HILL

24.95 24.95 29.95 29.95

VERBATIM

J

So soFT

Apple II Users Guide CRT Controller's Handbook 68000 Assembly Language Programming CBASIC User Guide

tc

The 8086 Book

16

E.

95 99

fe 99 `..

f

ao 99

SYBEX Your First Computer The CPIM Handbook From Chips to Stystems The PASCAL Handbook

8" _s

Rose

BOOKS BEST SELLERS

51/4"

Competitors Prices

D.

nelicy is available upon requesr

DISKETTES

Beat Any

L

we will where for less. tell us match or beat their price.

I

We Will

A copy of

It you see an item advertised else-

To better help us serve the needs of our customers, we have installed a new IBM System 34 Computer. This will enable us to reach our goal o' 100% Customer Satisfaction, tut we need your help - please use your customer number whenever ordering. Your permanent customer number can be found on the left -hand side of your computer printed invoice.

800 -538 -5000 800 -662-6279 IFORLIA

to

To make doing business with JDR

SPEEDY SERVICE!

ORDER TOLL FREE

1L

iS

-

$11995

L

VOLUME QUOTES

A LETTER FROM THE PRESIDENT

ZENITH MONITOR *

US FOR

8.95 14.95 14.95 18.95

Microprocessor Interfacing Techniques

44.95

17.95

L

APPLE* FAN

ADD ON

DISK DRIVE

$69°°

For Apple*

OUTLE ON

THE REAR OF THE FAN FOR A MONITOR - CONTROLLED BY THE S -''ITCH

*

ULTRA-QUIET APPLE FAN DRAWS COOL AIR THROUGH YOUR COMPUTER

*

* * *

ELIMIN4TES DOWN TIME SAVES REPAIR CHARGES INCREC SES RELIABILITY

Includes metal cabinet Color matches Apple* 35 Tracks /single side Includes cable Use with Apple* Il Controller

CLIPS ON -NO HOLES OR SCREWS

$375 °°

LONG !IFE, LOW NOISE MOTOR

'Apple

is a trademark of APPLE COMPUTER, INC.

J

L

JDR MICRODEVICES, INC. 1224 S. Bascom Avenue San Jose, CA 95128 800-.52-6279 (CA) 800-538 -5000 TE ex 171 -110 (408) 995 -5430 CIRCLE NO. 26 ON FREE INFO/MATION CARD

II

HOURS. Mon.

-

Fri., 9 to 5; Sat.

11

to

3

VISIT OUR RETAIL STORE! TERMS.

For shipping include $2.00 for UPS G-ound,

$3 00 for UPS Elue Label Air. $10.00 minimum order. Bay Area residents add 61/2% sales tax. California resi-

dents add 6% sales tax. We reserve the right to limit quantities and substitute manufacturer. Prices sub act to change without notice. Send SASE for complete ist.

LL

Ni!.RC:HAN1)ISL

(;(':1R,1V l

IUU%

STATIC RAMS 2101 5101 2102-1

(450ns)

256 x 4 256 x 4 1024 x 1 1024 x 1 1024 x 1 256 x 4 256 x 4 1024 x 4 1024 x 4 1024 x 4 1024 x 4 4096 x

pca

2102L-2 2102L-4 2111

2112 2114 2114L-2 2114L-3 2114L-4 2147 TMS4044-4 TMS4044-3 TMS40L44-2

(450ns) (LP) (250ns) (LP) (450ns) (450ns) (450ns) (450ns) (LP) (200ns) (LP) (300ns) (LP) (450ns) (55ns) (450ns) (300ns) (LP) )200ns( (250ns)

1

4096 x

MK4118 TMM2016 HM6116-4 HM6116-3 HM6116-2 HM6116LP-4 HM6116LP-3 HM6116LP-2

1.95 4.95 .89 1.69 1.29

1.85 3.95 .85 1.55 1.15

2.99 2.99 8/16.95 8/19.95 8/18.95 8/17.95 9.95 3.49 3.99 4.49 9.95

2.49 2.79

(cmos) (450ns)

1

4096 x 1 4096 x 1 1024 x 8 2048 x 8

8I6

3.75 4.25 call

4116-300 2118

MK4816 4164-200 4164-150

8I895

x 8

(lus)

x 8

TMS2516 2716 2716 -1 TMS2716 TMS2532 2732 2732A -2 2764 TMS2564

2048 2048 2048 2048 4096 4096 4096 8192 8192

x

(450ns) (450ns) (450ns) (450ns) (350ns) (450ns) (450ns) (450ns) (200ns) (450ns) (450ns)

x

x x x x x x x x

5v =

8 8 8 8 8 8 8 8 8 8

(5v) (5v) (5v) (5v) (5v) (5v) (5v) (5v) (5v)

Single

5

8/29.95 8/18.95 8/13.95 8/13.90 8/13.80 4.95 24.95 call

call

call call call

call call call call call

PL-265T PR-125T PR-320T

20 16

32

74LS73 74LS74

74LS75 74LS76 74LS78 74LS83 74L385 74LS86 74LS90 74LS91

8/395

call

call

74LS92 74LS93 74LS95 74LS96 74LS107 74LS109 74LS112 741S113 74LS114 74LS122 74LS123 74LS124 74LS125

ea.

32K EPROMS Each

8

2532 or 2732

pca

4.95 3.75

4.50 3.50

9.95 6.95 4.95 9 00 9.95 9.95 9.95 call call call

8.95 5.95 3.95 8.50 8.95 7.95 7.95 call call call

(450NS)

8/795

7415126 74L5132 74L5136 74LS137 74LS138 74LS139 74LS145 74LS147 74LS148

En.

PRICES GOOD FOR HE MONTH, OF JULY ONLY PLEASE MENTION JULY SPECIALS WHEN ORDERING,

74LS151

74L5153

Volt Supply

Capacity Chip 6 6 9

74LS55 74LS63

2716 (450NS)

74LS154

745188 745287 745288 74S387 74S471

X X X X X

74LS51 74LS54

16K EPROMS

1.95

EPROM ERASERS

PE-14 PE-14T PE-24T

EA

811 395EA

2.00

Order by National Part No.

Timer

74L638 74LS40 74LS42 74LS47 74LS48 74LS49

16K DYNAMIC

pca

2.50 1.95 1.85

EPROMS 256 1024 1024

74LS27 74LS28 74LS30 74LS32 74LS33 74LS37

4-64 (200NS)

L

1702 2708 2758

74L522 74LS26

64K DYNAMIC

loo

Each

4116 200 4116 250

74LS21

EA

4116 (200NS)

DYNAMIC RAMS MM5298 4116-120 4116-150

74LS05 74LS08 74LS09 74LS10 74LS11 74LS12 74L513 74LS14 74LS15 74L$20

E.

8I795

3.25

J

(250ns) (200ns) (250ns) (120ns) (150ns) (200ns) (250ns) (300ns) (5v)(150ns) (5v) (300ns) (5v) (200ns) (5v) (150ns)

74LSO4

HMS116 (200NS)

call

(15Ons)

4096 x 1 8192 x 1 8192 x 1 16384 x 1 16384 x 1 16384 x 1 16384 x 1 16384 x 1 16384 x 1 2048 x 8 65536 x 1 65536 x 1

74LS00 741501 74LS02 74LS03

TMM-2016 (200NS)

1.95 2.35 2.25 2.10

VOIT NIL

r 74LS00

2K x 8 STATIC

call call 2048 x 8 (cmos) (200ns) call call call call 2048 x 8 (cmos) (15Ons) 2048 x (cmos) (12Ons) call call 2048 x 8 (LP) (cmos) (200ns) call call 2048 x 8 (LP) (cmos) (15Ons) call call 2048 x 8 (LP) (cmos) (12Ons) call call Z-6132 4096 x 8 (Qstat)(300ns)34.95 call LP = Low Power Qstat = Quasi- Static

TMS4027 MK4108

c::11.1. US FOR

LID!

ALY SPECiaS

loo Each

N

Intensity (uWICM')

745472 745473

5,200 5,200 6,700 6,700 15,000 15,000

745475 745478 74S570 745571 74S572 74S573 875180 87S181 87S184 875185 875190

74S474

83.00 119.00 175.00 255.00 349.00 595.00

L

875191

74LS155 74LS156

PROMS Function

32x8 OC 256x4 TS 32x8 TS 256x4 OC 256x8 TS 512x8 TS 512x8 OC 512x8 TS 512x8 TS 1Kx8 TS 512x4 OC 512x4 TS 1kx4 OC 1kx4 TS 1kx8 OC 1kx8 TS 2kx4 OC 2kx4 TS 2kx4 OC 2kx8 TS

74LS157

EQUIVALENT PART NUMBERS MMI Harris TI SIG

18SA030 14S10 18S030 14SA10 18522 18542 18SA42 18546 18SA46 28S86 27S12

27513 24SA41 24S41

28SA86 28S86 24SA81 24S81

285A166 285166

.50 .75 1.15 .40 .65 .89 .70 .65 85

.95 .40 .40 .45 .45 .50 .45 .95

2.99 .95 .85 .75 .55 .99 .75 .75 1.20

2.49 1.35 .75 .75

2.35 1.15 .95 75 .75 .90 .95 .95 .95 .95 .95 2.40 1.75

7602

7640

12.95 12.95

825130 825131

6305

7620

19.95 5.95

6306-1

7621

5.95

825136 825137 82S180 825181 825184

6352.1

7642

9.95

6353-1 6380-1 6381-1

7643 7680 7681

7684 7685 76160

9.95 19.25 16.25 17.20 16.95 39.95

PN2222 2N2222 2N2907 2N3055 2N3904 2N3906

76161

3995

1N4148(1N914)

82S129

825123 825126 825147 82S146 82S141 82S140

825185 825190 825191

7611 7603

7610

7649 7648 7641

2.95 3.25 2.75 2.95 10.95 10.95 10.95

.45 .50 .40

6330.1 6301-1 6331-1 6300.1 6309.1 6349.1 6348 6341 6340

82523

JDR MICRODEVICES, INC. 1224 S. Bascom Avenue San Jose, CA 95128 800 -538 -5000 800 -662 -6279 (CA) (408) 995 -5430 Telex 171 -110

74LS158 74LS160

.25 .25 .25 .25 .25 .25 .35 .35 .25 .35 .35 .45 1.00 .35 .25 .35 .25 .35 .35 .35 .25 .35 .55 .55 .35 .35 .55 .75 .75 .75 .25 .35 .35 1.25 .40

74LS161

74LS162 74LS163 74LS164 74LS165 74LS166 74LS168

J

QUO"I-ES

SERIES 74LS169 74LS170 74LS173 74LS174 74LS175 74LS181 74LS189 74LS190 74LS191 74LS192 74LS193 74LS194

1.75 1.75 .80 .95 .95 2.15

9.95 1.00

1.00

74L5195 74LS196 74LS197 74L$221 74LS240

.85 .95 1.00 .95 .85 .85 1.20 1.29

74LS241

1.29

74LS242 1.85 74LS243 1.85 1.29 74LS244 74LS245 1.90 74LS247 .75 74LS248 1.25 74LS249 .99 74LS251 1.30 74LS253 .85 74LS257 .85 74LS258 .85 74LS259 2.85 74LS260 .65 74LS266 .55 74LS273 1.65 74LS275 3.35 74LS279 .55 74LS280 1.98 1.00 74LS283 1.25 74L$290 1.85 74LS293 74LS295 1.05 1.20 74LS298 74LS324 1.75 74LS352 1.55 74LS353 1.55 74LS363 1.35 74L5364 1.95 74LS365 .95 74LS366 .95 74LS367 .70 74LS368 .70 1.75 74LS373 74LS374 1.75 74LS377 1.45 74LS378 1.18 74LS379 1.35 74L5385 1.90 74LS386 .65 1.90 74L5390 74LS393 1.90 74LS395 1.65 1.70 74LS399 74LS424 2.95 .37 74LS447 74LS490 1.95 74LS624 3.99 74LS668 1.69 1.89 74LS669 74LS670 2.20 74LS674 9.65 74LS682 3.20 74LS683 2.30 74LS684 2.40 74LS685 2.40 74LS688 2.40 74LS689 2.40 74LS783 24.95 1.69 81LS95 1.69 81LS96 1.69 81LS97 1.69 81LS98

TRANSISTORS 1

`1N4004

HOURS: Mon.

-

10/1.00

100/ 8.99

.25 .25 .79

50/10.99 50/10.99 10/ 6.99 100/ 8.99 100/ 8.99

10/1.00 10/1.00

25/ 1.00 10/ 1.00

J

Fri., 9 to 5; Sat. 11 to 3.

VISIT OUR RETAIL STORE!

-

-

TERMS: Fcr shipping include $2.00 for UPS Ground, $3.00 for UPS Blue Label Air. $10.00 minimum order. Bay Area residents add 81/2 % sales tax. California residents add 6% sales tax. We reserve the right to limit quantities and substitute manufacturer. Prices subject to change without notice. Send SASE for complete list.

(:l'ARA\

ALI NII R(.l1A\I)111-. 100%

I

Z-80 6.00 5.95

2130-DART

8205 8212

15.25 17.50

Z80-DMA Z80-PIO Z80-SI0IO

8214 8216 8224 8228 8228 8237 8238 8243 8250

6.00 18.50

Z80-51011 Z80-51012 Z80-S1019

18.50 18.50 16.95

4.0 Mhz

Z80-A-CPU

Z80-CTC Z80A-DART Z80A-DMA Z80A-PIO Z80A-S10/0 Z80A-S1011, O

Z80A-SIOYi2 280A-S1019

6.00 8.65 18.75 27.50 6.00 22.50 22.50 22.50 19.95

8253 8253-5 8255 8255 -5 8257 8257.5 8259 8259-5 8272 8275 8279 8279-5 8262 8283 8284 8286

17.95 15.50 15.50

Z8013-PIO

ZILOG Z6132

34.95 39.95

Z8

1.80 2.50 1.80 4.90

8251

6.0 Mhz

Z80B-CPU Z8oB-CTC

34.95 3.50 1.85 3.85

8202

A

82137

8288 82139

19.95 4.95 4.45 14.95 4.75 9.25 9.85 4.75 5.25 8.50 8.95 6.90 7.50 39.95 29.95 9.50 10.00 6.65 6.65 5.70 6.65 6.50 25.00 49.95

IC SOCKETS 8 pin ST 14 pin ST 16 pinST 18 pin ST

1.99

100

.13

.11

.15 .17 .20 .29 .30 .30 .40 .49

.12 .13 .18 .27 .27

.89 .69 .99 1.09 1.39 1.49 1.69 1.99

.52 .58 .90 .98 1.28 1.35 1.49 1.80

pin ST pin ST pin ST .27 pin ST .32 pin ST .39 ST = SOLDERTAIL

20 22 24 28 40

14 pin WW 16 pin WIN 18

pin WW

20 pin WW

22pinWW 24 pin WW 28 pin WW 40 pin WW

WW = WIREWRAP

F.I

(:AI.[. US FOR VOI.I' NII. (.)VO

l)'

8000 SERIES

8200

2.5 Mhz Z80-CPU Z80-CTC

I

8035 8039 NS8060 I

IN58073 8080 8085 8085A -2 8086 8087 8088 8089 8155 8156 8155 8135 -2 8741

8748 8755

POSITION POSITION POSITION 7 POSITION 8 POSITION

6809E 6809

19.95 19.95

E810 6820 6821 6828 6840

2.95 4.95 4.95 14.95 12.95

8843 8844 8845

34.95 25.95

8847

8350 6852

9401 9601

9.95 .75

9602

1.50

96832

1.95

1.00

68800 68B02 68809E 68809 68810

DATA ACQUISITION ADC0800 ADC0804 ADC0809 ADC0817 DAC0800

3800 =

.85 .90 .90 .95 .95

MHZ

MHZ

800- 538-5000 800- 662 -6279

LM301 LM301H LM307 LM308 LM308H LM309H LM309K LM310 LM311 LM311 H LM312H LM317K LM317 LM318 LM318H LM319H LM319 LM320 (see LM322

LM323K LM324 LM329

.34 .79 .45 .98 1.15 1.95 1.49 1.75 .64 .89 1.75

3.95 1.95 1.49 1.59 1.25 1.25 7900) 1.65 4.95

.59 .69 LM331 3.95 LM334 1.30 LM335 1.40 LM336 1.75 LM337K 3.95 LM337T 2.95 LM338K 6.95 LM339 .99 LM340 (see 7800) LM348 1.20

LM350K LM350T LM358 LM359 LM376 LM.;77

5.60 4.60 .98 1.79 3.75 2.29 2.50 Lm:: 78 4.50 LM:: 79 1.29 LM 80 LMZ80N-8 1.10 1.60 LM581 1.60 LM382 1.95 LM383 1.95 LM384 1.50 LM386 1.40 LM387 1.35 LM3B9 1.95 LM390 LM392 .69 3.60 LM394H 5.00 LM399H NE531 3.75 6.00 NE536 NE555 .39 NE556 .69 1.50 NE558 -9.95 NE531 6.00 NE562 3.95 NE564

LM535 LM556 LM567

.99 1.49 1.29

NE570 NE571 NE592 LM703 LM709 LM710 LM711 LM723

.59 .75 .79 .49 .55 LM723H LM733 .98 LM 741 N-8 .35 LM741N-14 .35 .40 LM741H .79 LM747 .59 LM748 2.75 1014 LM 1.95 LM 1303 1.19 LM1304 1.49 LM1305 LM1307 .85

LM1310 MC1330 MC1350 MC1358 LM1414 LM1458 LM1488

2.90 1.89 1.89 1.29 1.79 1.59 .69 .99

LM 1489 LM 1496 LM 1558H

.99 .85 3.10

MC1349

LM1800 LM1812 LM1815 LM 1818 LM 1820

LM1830 LM1871 LM1872 LM1877 LM1889 LM1896 LM2877 LM2878 LM2900 LM2901

LM3900 LM3905 LM3909 LM3911 LM3914 LM3915 LM3916 MC4024 MC4044 RC4136 RC4151

LM4250 LM4500 LM 13080 LM 13600 LM 13700

2.99

TL071

14.95

32.768 khz 1.0 mhz 1.8432

3.95 4.95 4.95

2.0 2.097152

3.95 3.95 3.95 3.95 3.95 3.95 3.95 3.95 3.95 3.95 3.95 3.95 3.95 3.95 3.95 3.95 3.95 3.95 3.95 3.95 3.95 3.95 3.95 3.95

L7103 L7106 L7107 L8038

8.25 5.20 2.90 3.50 3.50 5.49 5.49 3.25 2.49 1.75 2.05 2.25 .85 1.00 .59 1.25

TL072 TL074

.98

2.25 3.95 3.95 3.95 3.95 4.50 1.25 3.95 1.75 3.25 1.29 1.49 1.49

TL081

TL082 TL083 TL084 LF347 LF351

LF353 LF355 LF356 LF357

TI TL494 TL496 TL497 75107 75110 75188 75189 75450 75451 75452 75453 75454 75491 75492 75493 75494

*zr# JDR MICRODEVICES. mastoc Cf large

1224 S. Bascom Avenue San Jose, CA 95128 800 -662 -6279 (CA) 800- 538 -5000 (408) 995 -5430 Telex 171 -110 CIRCLE NO. 26 ON FREE INFORMATION CARD

1

4.20 1.65 3.25 1.49 1.95 1.25 1.25 .59 .39 .39 .39 .39 .79 .79 .89 .89

XR XR XR XR XR

2206 2207 2208 2211 2240

I

¡

INC.

4.95 3.95 12.95 1.49 7.99

AY3-8910 MC3340 95H90 11C90 8202A 3242 MC3480 MC4024 MC4044 3205

13.95 34.95 7.95 9.00

3.95 4.50 3.50

BIT-RATE GENERATORS 9.95 9.95 12.95 16.95 10.95

14411

BR1941 4702

COM5016 M M5307

UARTS AY3-1014 AY5-1013 PT1472 TR1602 2350 TMS6011 IM6402 IM6403 N S8250 I

6.95 3.95 9.95 3.95 9.95 5.95

'.95

8.95 14.95

KEYBOARD CHIPS AV5-2376 AY5-3600 74C922 74C923

11.95 11.95 5.25 5.50

J

L

-CLOCK CIRCUITS 4.95 4.96 8.95 11.95 8.95

M M 5375 M M 58167

MM58174

MSM58X

RCA CA 3010 CA 3013 CA 3023 CA 3035 CA 3039 CA 3046 CA 3053 CA 3059 CA 3060 CA 3065 CA 3080 CA 3081 CA 3082 CA 1083 CA 3066 CA 3089 CA 3906 CA 3130 CA 3140 CA 3146 CA 3160 CA 3401 CA 3600

2.95 2.29

MISC

MM5314

3.75 3.85 3.90 5.25 3.25

1.69 2.49 .99 .99 .99 .99

3341 76477

9.50 9.95 12.95 3.95 5.59 15.95

M7107A

EXAR .79 1.19 2.19 .79 1.19 1.19 2.19 2.19 .60 1.00 1.10 1.10 1.40

INTERFACE 8726 8728 8795 8796 8797 8T98 DM8131 DP8304

INTERSIL

I

BI FET 4.75 3.95 2.75 .89

2143

3 MHZ

M7208

LINEAR

1797

28.50 12.95

10.0 14.31818 15.0 16.0 18.0 18.432 20.0 22.1184 32.0

ORDER TOLL FREE

LALIFORNtA RESIDfl

1795 6843 8272 UPD765 1691

5.0

12.95

63E100 = 2

1793

9.95

5.0688 5.185 5.7143 5.9904 6.0 6.144 6.5536 8.0

35.95

24.95 36.95 44.95 54.95 54.95 42.95 32.95 33.95 13.95 13.95

1171 1791

11.70 12.40

2.4576 3.2768 3.579535 4.0

7.95 12.95

1

DISC

CONTROLLERS

CRYSTALS

10.95

63B45 63850

5.55 4.95 5.25 10.95 4.95 4.95 8.25 5.95

`6502B

22.25 29.95 29.95

68B21

7

6.95 6.95 8.95 9.95 4.35 8.75 11.25 22.50 11.85 2 MHZ

10.95 11.95 6.95 2.95 24.95 24.95 19.95

3880 3383 38047 38488

3000 SERIES

MHZ

6502A 6522A 6532A 6545A 6551A

16.95 12.25 3.45 5.75

%75

3.25 3.75 1.25 3.95 4.95

DIP SWITCHES

6

6808

MC'408L8

CONNECTORS

5

4.95 10.95 13.90

802

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DAC1022

4

6800

3360

DACA808 DAG1020

RS232 MALE RS232 FEMALE RS232 HOOD S -100 ST S -100 WW

1

8.95 29.95 39.95 39.95 29.95 32.00

2.50 3.95

6500 SERIES

6502 6504 6505 6507 6520 6522 6532 6545 6551

call

E65300

7.95

9316 9334 9368

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7.25 7.95 17.96 29.95 3.95 7.95 11.95 59.95 Call 39.95 89.95

F.ti

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FUNCTION GENERATORS

.99

MC4024 LM566

2.00 2.75 2.49 1.29 1.25 1.45 2.90 2.90 1.75 1.10 1.65 1.65 1.55

XR2206 6038

Dual VCO

Function Generator Function Generator WavEfo-m Generator

3.95 1.49 3.75 3.35

VOLTAGE REG's 7805T 7808T 7812T 78157 7824T

.80 2.99 3.49 1.30 1.15 1.85 1.19 .59

79

99 79 99

78L12 78L15

LM309K LM317T

149 195

78L05

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HOURS: Mon.

.89 .89 1.19 1.19

7905K 7912K

1.49 1.49

79L05

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79L12 79L15

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99

139 139 139 89 89 89

7805K 7812K 7815K

3.45

7905T 7912T 7915T 7924T

LM317K LM323K LM337K

K = TO-3

Fri.. 9 to

.'9

5:

Sat.

L

3.25 4.25

3.25

= TO-92

11

to 3

VISIT OUR RETAIL STORE! TERMS: For shipping include $2.00 for UPS Ground, $3.00 for UPS Blue Label Ai $10.00 minimum order. Bay Area residents add 6'/23k sales tax. California residents add 6% sales tax. We reserve the right to limit quantities and substitute manufacturer. Prices subject to change without notice, Seid SASE for complete list. .

,. 00

rTppE4 SN7400N SN7101N SN7402N SN7403N SN7404N SN7105N SN7406N SN7107N SN7406N SN7409N SN7410N SN7411N SN7412N 5N7413N SN7414N SN7416N SN7417N SN7420N SN7421N SN7422N 5N7123N SN7425N SN7426N 5N7427N SN7428N SN7430N 5N7432N 5N7137N 5N7438N 5N7139N SN7440N 5N7441N 5N7442N SN7443N 5N7444N SN7445N

SN746N 5N7447N SN744BN 5N7450N SN7451N 5N7453N SN7454N SN7459A 5N7460N 5N7170N 74LSOO

74L501

703 1L5

.20 .20 .25 .25 .25 .29 .35 .35 .29 .29 .25 .29 .35 .40 .69 .29 .29 .25 .29 .45 .29 .29 .29 .25 .49 .25 .29 .25 .40 .25 .20 .89 .59 1.10 1.10 .89 .79 .69 .79 .20 .20 .20 .20 .25 .20 .29

.

5

74L511 74L512 71L513 74L574 74L515 74L520 74L521

.39 .35 .59

74L530 74L532 74LS33

74L537 7LS54880

74L542 74L547 74L588 74L549 74LS51 74L551 74L555 741.573 74LS74

74L575 74L576 74L578

XLS83

74L56 74L5B6

74L5%

5N7488N

5N74%N 5N7491N 5N7412N 5N7493N 5N7494N 5N74%N 5N7496N SN7497N 5N74100N 5N7410414

SN74105N 5N74307N SN74109N 5N74116N SN74121N SN74122N SN71123N 5N74125N SN74126N SN74112N 5N74135N SN74141N 5N74142N 5N74143N 5N74144N 5N74145N 5N74147N SN74148N SN74150N 5N74151N SN74152N SN74153N 5N74154N SN74155N

.35

.35 .35

.99 .35 .35

.35 .35 .35 .ä35

.35 .35 .59 .45

.

71L592 74L593 74L595 71L596 71LS107 74x5103 74x5112 71x5113 74L5114 71L51Z2 74L5123 74x5125 74L5126 71L5132 71L5133 74L5135 74L5135 71L5139 71L5151 7/L5153 74L5154 74x5155

7/L516 741_5157

.89

7/L5188

.

74L5160 74L5261 74L5162 74L5163 74LSI64

3.ÌÓ 1.15

.35 .35

.35 .45 .45 .59 .45 .49

.69 1.25 .49 .69

.29 .35 .35 .49 .35

5.00 .50 .99 .69 .89 .35 1.75 .49 .59 .45 .45 .69 .69 .69

3.00 1.49 .89 .89 .35



1.95 .39 .55 .59 .49 .49 .75 .75 .99

3.25 3.49 3.49 .79 1.95 1.29 1.25 .69 .69 .79 1.25 .79

74LS

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74LSn

5N746N

.29

74L505 74L5oB 74L

7/L522 7/L526

SN7472N 5N7173N 5N7471N 5N7175N 5N7476N 5N7479N SN7480N SN7482N SN7483N SN7485N

71L516

74L5168 74L5169 74L5170 74LS173 74L5174

7/L5175

.75 .75 .99 1.15 .45 .45 .45 .49 .19 .89 1.25 .59 .59 .99 .89 .49

.89 .89 .89 .89 1.75 .89 .89 .89 .89

1.15 1.15 1.15 1.15 1.15 1.15 1.19 1.19 1.95 .99 .99 .99

74L5181 74L5190 74L5191

2.95 1.25

1.5

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rfir SN74156N SN71157N SN74160N 5N74161N SN74162N SN71163N

SN7416N SN7416N 5N7416N 5N74167N SN74170N 5N74172N SN74173N 5N71174N 5N71176N SN74176N 5N74177N 5N74179N SN74180N SN74183N SN74182N SN74188N SN74185N SN71190N SN71191N SN74192N 5N74193N 5N74194N SN74195N SN741%N SN74197N SN74191N SN74199N 5N74221N SN74251N SN74276N 5N74279N 5N74283N SN74284N

5N7126N 5N74365N SN74366N 5N74367N 5N74388N SN71790N 5N74393N 74LS192 74L5193 74L5191

74L5195 74L5197 74L5221 74LS210 74L5241 74L5242 74L5243 74L5241 741_5245 74 L5247

71L5218 74L5249 74L5251 74LS253 74L5757

74L52M 74L5260

74L526 71L5273 71L5279 71x5283 74x5290 71L5293 74L5298 74L5352 74L5353 74

L536

74L536

74L5367 74L5388 74LS373 74 L5374 74LS375 74LS386 74L5393 71L5399 74L6670

OILS% 81L597

A.AMBERR.RED Y. YELLOW

01.31.0 .79 .69 .89 .89 .89 .89 .89 .89 1.25 2.79 1.95

74502 74503 74504 74505

7456 74509 74510 74511 74515 74520 74522 74530 74532 74538 74540 74551 74564 74565 74571 745% 745112 745113 745114

CA3010H CA3013H CA7023H CA3035H CA3039H CA3016N CA3059N C D4000

CD4001

Co002 C 0400 CD{007 C04009 C04010 C:4011 C04012 CD1013 C

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C.015 CD4016 CD4017 C04018 CD4019

CD40n 004021 CD4022 C04023 CD/024 C 04025

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3.5 2.09 1.35 1.30 3.25

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1.95

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2.% 1.59 1.59 2.95 1.95

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CA-LINEAR CA3060N CA3080H CA3881N CA3082N CA3063N

CA366N

3.25

1.5

2.00 2.00 1.60 .85

.39 .39 .39 1.19 .25 .49 .49 .39 .25 .49 1.39 1.19 .59 1.19 .99 .49 1.19 1.39 1.19 .29 .79

CD-CMOS

745260 74S280

745287 745288 745373 745374 745387 745471 745472 745473 745474

745475 745570 745571 745572 745573 745940 745941

CA369N CA30%N CA3130H CA3140H CA3160H CA3401N CA3600N

1.39 .99 .89 .79 .79 1.49 .79

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C04518 C04519

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C04583 CD4588 C04723 CD4724 MC14409 MC14410 MC14411 MC14412 MC14119 MC14433 MC14538 MC14541

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36,186

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STANDARD DBES SERIES CABLES

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M

3.86

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Pert No.

Con.tto

CON LS11pO

LM36H

LM307CN LM308CN LM309H LM309K LM3IOCN

LM311/CN LM312H

LM3I7MP LM3I7T

74C792 74C197 74C195

LM340T-5

LM341P3 LM341P-12 LM341P-15 LM342P-5 LM342P-12 LM342P-15 LM348N

.35 1.95 1.95 .99 .46 1.00

1.% 1.25

1.5 .90 2.49

L1/1323K

5.95

LM324N LM329DZ

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LM3342 LM335Z LM336Z LM337T LM337MP LM338K LM339N LM34OK5 LM340K-12 LM310K-15

1.30 1.40 1.75 1.95 1.15

5.75

LM36N

1.5

LM361N LM382N LM384N

1.95 1.79

.60 1.00 1.10 1.10 1.00 1.79 4.49 3.25 2.95

1.%

LM387N LM389N LM392N LF388N LM319H TL494CN TL496CP NESIOA NE529A NE53IH NE536H NE540H NE544N NE550A

.99

3.95

LM350K LF351N LF353N LF355N LF356N LM358N LM359N LM370N LM373N LM377N

LM36N-3

1.5

LM33IN

1.25 1.25 1.25 .75 .75 .75 .69 .69 .69 1.25

LM31OT-12 LM340T-15

2.19

1.25

1.59

LINEAR

4.50 4.75

1.5

Price

s

Value

LM556N NE561N

.99 1.35 1.35 1.35

1.95 2.25 2.25 2.49 2.59 .69 .69 10.95 10.95 1.69 10.95 5.49 5.75

74C917 74C922 74C923

74C925 74C926 80C96 80C97

1.50 7.50

LM703CN LM709N LM710N LM711N LM723N LM733N LM739N

3J9

.79 .79

.79

.69 1.00 1.19 .35 3.00 .79 .59 2.75 1.95 .59 1.25

1.5 1.95 1.75

2.95 5.49 5.49

35

LM169N

3.20 1.15 1.49 2.05 2.25 2.25 2.95

LM1886N LM2002T

LM/900N

1.30 .39 .99

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MC171ISCG LM747N LM748N LM1014N LM1310N LM1158CN LM1488N LM1188N LMI496N LMI556V LM1880N LM1871N LMI872N LM1877N9

4.00 6.00 4.49 6.00 4.95 3.96 6.00 6.00 4.95

.29

LMMICN

LM577P

NE56V

6.95

74C221 74C240 74C244 74C373 74C374 74C901 74C903 74C911 74C912 74C915

1.29 1.45 1.35 .69

1.5

2.50 2.95 2.95

LM2878P LM23%P-1

LM316N

.69

LM396CN

1.5

LM3909N LM3914N LM3915N LM3916N RC4136N RC4151N8 RC4194TK RC1195TK LM4500A ICL8038B

1.15 3.95 3.95 3.95 1.25

LM1306N

3.95 6.95 5.49 3.25

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7513874

1.29 1.49 1.95

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75450N

.89

1.25

75451CN

.39

4.95

75492

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395

LM65N LM56CN LM67V

1.5

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LM13600N

50 VOLT CERAMIC DISC CAPACITORS

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100 VOLT MYLAR FILM CAPACITORS

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.10 .10 .10 .10

07 .07 .07 .07

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.11 .17

.11 .51 .63 .63 .79 1.39 .79

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27

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D823P4A D925P.45

4feet

2-DB25P

1515 se.

4 70

41eet 1.13525P/1 DE1255 4 feet 20026

17.%.

1355 SHOREWAY ROAD, BELMONT, CA 94002 PHONE ORDERS WELCOME (415) 592.8097

.05

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ELECTRONICS

.00140F .00734F 01µµF

100 pf 220 91

7.6

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.6

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.6

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World..

Value

.06

88

10.%581

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1099 100+

pf

47

08255

25e each Spec Sheets Send 88e Postage for your FREE 1982 JAMECO CATALOG Prices Subject to Change

.08 .25

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1-9

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72

1-DB25P

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74C175

LM320T-12 LM320T-15

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74C174

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LM320T5

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U.S. Funds Only

74C163 74C164 71C173

1.%

LM320K-12 LM320K-15

LM320K5

1.59 1.69 2.95 3.95 2.25 1.69 1.60 1.49 1.69 1.59 1.39 1.39 1.19 1.69 1.69

740162

6.95

1.15 1.75 3.95 1.95 1.95 1.35 1.35 1.35

LM317K LM318CN LM319N

DB2554

1302554.s

74C107 74C151 74C154 74C157 74C160 74C161

LHOOMCD 36.6 LM300H .99

13825P4

62

Postage Add 5% plus $1.50 Insurance Send S.A.S.E. for Monthly Sale Flyer!

7/82

owl

6.72

Now vnv can order D575 P or S connectors wire the Choose from cable cecan to fit your Our w endrd r flat cable in 4-foot length. Cod today. STANDARD CABLES

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California Residents Add 8% Sales Tax

1795

" 3e" Y' 24

1.72

29

-

0.01 02.1

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.39 .39 .75 .39 .39 .39 1.39 1.96 .19 .79

1.29

LM301CN LM302H LM304H

74C

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7.50 2.95 4.95 21.60

CAPACITOR CORNER

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92412676

2.6

N'

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924128 24

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38"

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92412612

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STANDARD DIP JUMPERS All Iy

pine for 2X784.

Clock Generator 4 Funt. CMOS Stopwatch CKT 4 Funt. Stopwatch Chip, XTL 8-Digit Unlo. Counter C.A. MDigit Freq. Counter C.A. 8 -Digit Freq. Counter C.L. 4.01012 LED Up/Down Counter CA 501519 LED Up/Down Counter CC LCD 4% Digit Up Counter DR! 501811 Univ. Counter 5 Function Counter Chlp, XTL 4.95 CMOS Bin Prog. Timer /Counter CMOS 010100-179.256 RC Timer 245 6.00 CMOS BCD Prog. Timer /Counter CMOS BCD Prog. Timer /Counter 6.25 CMOS 56 Timer (8 pin) 1.6 CMOS 556 Timer (14 pin) 2.20 CMOS Op Amp Comparator 5MV 2.25 5MV 2.95 CMOS Op Amp Ext. Cmm, CMOS Dual Op Amp Comp. 5MV 3.95 CMOS Trl Op Amp Comp. IOMV 5.35 CMOS Quad Op Amp Comp. 101AV 7.50

LH0E70-OH 4.95 TL071CP .79 TL072CP 1.39 TL074CN 2.49 LH0082CD 35.6 TL882CP 1.19

JUMPER AND CABLE ASSEMBLIES

Jumpers!

Seven Decade Counter

.A

6.6

PRICE

Freq. Counter Chip, XTL

Monolithic Logarithm C Amp 500pm Band -GAP Voll Rel. Diode Volt Ref /Intliutor Volt Ref /Indicator

LMIICLH

WYDC

286

t

6 6

24150

MFD

2:154

3

16 10

OVER 200 OTHER VALUES AVAILABLE

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PRICE

55 16 16

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155

WVDC

Oscillator Controller

Voltage Converter Waveform Generator

806CCPE 869CCQ

LMIOCLH

tam

Tone Generator Tone Generator Chip, XTL

CMOS Quad Op Amp Comp. IOMV

7642CCPO 7660CPA 8088CCPD

LH0002CN

1/2.6

co

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7631CCPE

21135

21286

106.x.

7561PD 7611BCPA 7612BCPA 7621BCPA

1/L6

212A

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72421JA 72901JE 7260IJE 7555IPA

1.29

COMPUTER GRADE CAPACITORS MFD

7226AIJL 7226AEV

74C6

4666 A..owan

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72241PL

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Digit A/O (LED Drive)

IC. Circuit Board, Display

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49 3.49 2.95 10.95 10.95 10.95

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1.35 1.35 .79 2.95

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LITRONIX- NATIONAL Stick Display Sale

1.15 1.15 1.15 1.15 1.19 1.19 1.49 1.49 1.49 1.49 1.49 2.95 1.19 1.19 1.19 .99

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74553 74557

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.79 .39 .45 .55 .49 .49 .39 .39 1.39 .55

2.95 .69

745243 745244 745251

DISPLAY LEDS

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C.CLEAR

8142434.0111/1111.876

Á7/35V 66 /35V 1.0/35V

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1.5

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MINI. ALUMINUM ELECTROLYTIC CAPACITORS

Axi.I 17/50V

199 100.499 500+ .10 .I6 .14

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1-99

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170/SV 4700/16V 2200/1612

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27

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Mini Stereo AM /FM Receiver

UTIC

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Bit

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e i.Dir «tonal BU Driver Clock Omerator /Driver B ut Driver System COntroller/Bin Driver System Controlar 1/15 Sapant./ for N NS l

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Part No.

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211.98

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$1.39 or 212.98

MOU

MC6C2CP MC(410API

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MC1121

MC6131

MC2464LI MC6150

MeseM MC_NO

MC6ë2 4C6110Á

1.95

Priority interrupt Control )« 102.41111 ROM 14C%Á04) Asynchronous Comm, Adapter Synchronous Seri. Data Adapter 04070os Digital MODEM 24070.MOdu Mtor Oued y5tata 9us.Trans.04.726I

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175.0011011

55.1054 Nt riSMitOs PIO%

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CPU CPU

2.49 11.55

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9.95

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2.%

10241511

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Manu

AFI07-ICN

Erases 2708, 2716, 1702A, 52030, 52040, etc. Erases up to 4 chips within 20 minutes.

ÁF121 -1C1

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Maintains constant exposure distance of one inch. Special conductive foam liner eliminates static build -up. Built -In safety lock to prevent UV exposure. only 7 -5/8" x 2 -7/8" x 2" Compact Complete with holding tray for 4 chips. UVS -11EL Replacement Bu lb $16.95

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13312 LM313 LFSSN

%DC /IX Con./ 45v to 9V Fumoir Disc Rad AMP System

515

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$79.95 JOYSTICKS

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110

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4M aKb

1.15

2c f

3.50

193

117V6OH2 117V/60Hz 117VI60H4 117V180H2 1209/60H2

DC89121aboyel OV9200

DC900 DC1200

line from adapter to plugs sic Inch line Irom adapter to battery snap. 120VI60H2. 300mÁ. Output Prim

12VAC 250mA 12VAC 500mA 12VAC amp

$3.95 54.95

1200/8003 1170/8002 120V/6000

9VAC 1.7 amp 8VDC 400mA (ball. charger) 09,12VDC 300mA 9VDC 200mA 9VDC 500mA

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S396 Si 95 59.95 53.25 $3.95 S295

1

300.0

CONNECTORS D-Subminiature Plug D- Subminiature Socket SttawLock Hdwr,12) DB25S/P Cover for DB25P/S

DB25P

DB51226 22/445E

11.96

En

an tan I.%

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UG89/U UG175/U 50239 PL258 PL259 UG260/U UG 1094/U

$2.95 $3.50 2/5.99 51.75 $2.95 $1.79 $3.79 $ .49

UHF Panel R.cp UHF Adapter UHF Plue

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BNC Plug BNC Bulkhead Recp.

TRS -80 16K Conversion Kit Expand your 4K TRS.80 System to 16K Kit comes complete with: MM5290 (UPD41 8/4116) 16K Dyn. Ram (ns) Documentation for conversion

8 ea.

TRS -16K2 TRS-16K3 TRS-16K4

150ns 200ns

$19.95 $16.95 $14.95

250ns

Mostek DC/DC Converter

11.% S.

P.C. Edge 122/44 Pin)

U(1BB/U

1391

14.95

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+5 VOLTS TO -9 VOLTS Input: +5V. Output.'9V (regulated) 42 30mA. PrInted circuit mounting, $2.95 ea. or 2154.95

DC10

JE610 ASCII Encoded Keyboard Kit

delivery 1.50" depth.

aéLeaé c

iyra.cont. mpae

blentbÓC

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e-glì se.

x.

f/496aa.

PO/52107F

RAM

Genet«

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Input

AC 250 AC 500 AC1000 AC1700 DC 800

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For Apple users

PWB2107U=ette

seta

105c 4.66" sq.

38ctm free air delivery 3.125" K. o 1865" de ih 1100 yrs. cont. duty at

JS-5K

9.% e.%

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Part No

020418-2

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96/141-Kw Serial Keyboard Encodai

Pee Wee Boxer Fan 11

MeturBe Char. Pen.

rd Encodai 00 keys) Keyboard Encoder IN keys) Keyboard Encoder Is keys) Keyboard Enta», la keys) 411

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1313255

13.50 13.50

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[roll« with

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1.15

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Universel

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Dual MOS Clack Driver 0413) Dual MON Clock Driver (SMZ) FloPPV DIN Controller CommunlNllon Chip Mlcroprocesor Real Time CIOCk ralaroprOvAMOr Compatible Clock

M 51167N MMi1124N

62,66

boit D/A Convener (DACeeLC51

4.95

SPECIAL FUNCTION NSImN-1 IN5s61N

517.611

DATA ACQUISITION DC10

S%

B

Selective vollegot. 8.9,12V DC Polarity selection (+ /-). «x.lool

1%

User Manuel

DSe49CN DSOSCN

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Dynamic Cio ION. NI

2.% 1.96

Transformers 1V 1 ery Snap

With Universel Plug and

1.«

User Manual

CDP1402 M.2650

Part No. DC6912

14.%

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notes for Intel peripheral device

aveu)

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I.%

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dials,

17.95

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256-Bit Dynamic 151.611 Dynamic /Accumu

1,95

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$14.55

AC and DC Wall

9.05

Character Oeneratur (Upper Case) Character Oene,.tor (Lower Case)

151312140)

Dus( 54B1í Dynamic Dual 1001511 Static DV Accumulator

,M

595 4.%

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1,951

Full data

componels

1.95

p.%

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4.95

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4696 611.65

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1.49

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1K EPROM 140,.6V,014V1 2716..114916I71 aK EPROM( MON %V) 2701nta1 Ti LK EPROM 2%I IK EPROM 050551 (Single.SVl

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2.95

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CPU-4-Bit Sl la (COm. Tamp- Orad. 19.6 Mou w /Clock %K Bytes memory) 11% 7.96 MPU -1-B1í (6Ha) CPU- 5e1.Ct5p1- Bit(l%byt«RAM) 9.95 24.% CPU (149 Bytes RAMI

1139 OS

mec LM, LF, AOC, DAC, LH Serbe National SerlesBO- Board LevelCompuber 1224page» National TL Look Deer Book 1624 papal 7400,LS.L,H.S. and OMM Series

2.14

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(OMUO)

Converters

2.49

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DS3800, 0375000, etc.

11378

1.% 195 4.16

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625E

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30003

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30006 Above (3) 30001,3,5 as set $24.95/lot

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Hke61164

IÑtioonnal Interface

6.95

La

Dynamic Fun, Dacori% 20.1 Dynamic 4016et Dynamic M6Ca) 16K Dynamic ISOns (UO SK Dyn. Kens power Vol 4452%,11 I6K (2K41) Static 05ons K 91t RAM 116.001 1K Dynamic I1-pin 414 Static

4.52%J9Á

6.95

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1024.1

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MICROPROCESSOR CHIPS

A National Semiconductor

5101

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1.19

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5.15

14.95

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3.05

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Dynamic 056 %

2101111011

l.%

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1101

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o%

DCnanml Mult101a.er %K BAUD UART

1101

8800 /6800 SUPPORT DEVICES MCMX

MOU D/A Converter

CDbIN Avg-1011

50.% 9.%

Octal Latched Panpnarai Orive, Octal Latched Parlpnaral Driver

DP.11

149 4.%

6.% a.% 505 9.% 9.%

m...

SPEAKERS

DACIOILCN DACIeeLCN

BOOKS - inter% - Intel

30001

5.49

10-Bit 0/A Cana. Micro. Comp. 10.%5111% 10-BIt D/A Co.. Micro. Comp. 10.2051 0.09 10-Bit D/A Converter (0.0615 Lin.) 536 146110/A Converter (0.2Pí LM.)

%etas

1

$34.95

List Price $89.95

1%

IS-Ch. Multl-1

0BIt A/DCOnverter/liCrr. Munl.l

ADC%ItCCN DACI LCP

9.95

AtyrahrOn0Us Comm. Element op. Comm. /0IUSARTI Prop. Interval Timer Prop. wnpneral I/O (0011 Pres. DMA Control Pro. Interrupt Centro) 4op. CRT Controller op. Keyoeara /Display 5ystam Timing Element 1-611 el.Oirect ionei Receiver

tait A/O Convaer

ADC%SICCN

3%

5i

FEATURES: Lightweight headphones. Left/right balance control. Full fidelity stereo sound. Additional black soft carrying case & shoulder strap. Belt clip (hands free). Operates on 3 AA cell batteries (not incl.). Compact size: 3%" x 4%" x 1 ". Wt. 6 oz.

ICONTINUEDi-

DATA ACQUISITION

4.% 115 5.% 114

c PU

KEYBOARDS MICRO SWITCH 139-KEY KEYBOARD Uses AMI SW20350K Chip. SIZe: lBñ "L grey key caps (no dala shoot).

it JVCJO JS-5K JS-100K JS -150K JVC -40

5K Linear Taper Pots 100K Linear Taper Pots 150K Linear Taper Pots 40K (2) Video Controller in case

51/4'r

$5.25 $4.95 $4.75 $4.95

H

L1rn Ssd

Duesll fy1

FD200

$179.95

FD250

$199.95

SPS7 Switching (Meohenicall. Size: 13"L Sheets are avallable. Part No. K-82 (ASCII Encloded Keyboard Kit JE610K

Description: The JE215 is a Dual Power Supply with independent adjustable positive and negative output voltages. A separate adjustment for each of the supplies provides the user unlimited applications for IC current voltage requirements. The supply can also be used as

e

supply.

FEATURES: Adjustable regulated power supplies, pos. and nag. 1.2VDC to 15VDC. s Power Output (oath supply): 5VDC W 500mA, 10V DC 750mA, 12VDC P 500mA, and 15VDCD 176mA. Two, 3- terminal adj. IC reguleton with thermal overload protection. Heat sink regs/Jeter cooling LED "on" indicator Printed Board Construction 120V AC Input Size: 3 -1 /2 "w x 51/16 "L x 2 "H

JE215 Adj. Duel Power Supply Kit les shown) . . (Picture not shown but similar in construction to JE200 Reg. Power Supply Kit (5VDC, 1 amp) .1E205 Adapter Brd.Ito JE200115,19 K r 12V, JE210 Var. Pwr. Sply. Kit, 5- 15VOC,to l.5amp. .

JULY 1982

170.151

Uses SD 25010E Chip (AM». Size: 19'A "L x 53/4"W a 1k, "H. Dark and light gray key cape. Used in a Diablo 1840 Terminal (achemailc avail.)

Pert No. 885022

$69.95 each

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1.5 amp. Input 115VAC60H3. Circuit breaker reset button. Black selfenc10000 use with 4 rubber feet. B loot, 3 conductor black power cord. On /off switch. Sloe: 83 "W x 7,4 "D x 3% "H Wt. 7 lbs.

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The JE610 ASCII Keyboard Kit un be interfaced into most any computer system. The kit comes complete an Industrial grade keyboard switch assembly 162-keys), IC's, sockets, connector, electronic components and a double -sided printed wiring board. The keyboard assembly requires +5V M 150mA and -12V rP 10 mA for operation. Feeteres. 60 keys generate the 126 characters, upper and lower case ASCII set. Fully buffered. Two user-define keys provided for custom application. Ceps lock for upper-case-only alpha cherac tars. Util nos a 2376 (40 -pin) encoder read -only memory chip. Ototputs directly compatible with TTL /DTL or MOS logic array. Easy Interfacing wIth a 16 -pin dip or 18 pin edge connecter. Sloe: 319 "H x 1419"W x 815 "D

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The Chgueey volume discount and handing charges ore pmple to apply. Most awn sold by Dgi-Ely may be combined for a volume discount. Items that ore not discountable are tdentified by the sufflyWD following the port number Alter w Wing your order totol oll of Me discountable dams and apply the appropriate 011000! To this subtotal, odd the nor...discountable items. Then odd the handling chorge. We pay all shipong and onsuronce to addresses in Me USA,. Canada and Mexico when check or money ode! accompanies order. S 10.00-525.00 5 25.00-549.99 WREN ORDERING ET NONE, CAM, 1.11012346.5144 (Mo., R., NI., NEI 211411.9E74) By =ERR yon who to: MEW. MENvoy 32 SRN, TNM MOM Rh, MN SE7111 You may poy by check. money order. Master Charge. VISA m C.O.D DIGI-KEY GUARANTEE: Any ports or products purchased from Digi.Key Mot prove to be defective will be 11 50.00.399.99 g100.00 8 Up replaced or refunded if returned within 90 days frorn receipt with o copy of your invoice. Prase sutural lo change wol.ot not..

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By Forrest Mims III

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A top-quality solar cell pre -wired to a

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Gives you practical circuits for most analog and digital ICs. Awealth of information, presented in an easy -to-read format. 128 pages. Punched for three -ring binder. 276 -5002 2 49

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Now That It's Working

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Description Male for RS -232 25 -Pin D -Sub Female 40- Position Card -Edge 34- Position Card -Edge D -Sub

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276 -1559 276 -1565 276-1558 276-1564

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POPULAR ELECTRONICS

101

RATE: Ads are 2" by 3". 1 insertion: $550.00. 6 insertions: $525.00 ea. 12 insertions, $500.00 ea. Closing date: ist of the 2nd mo. preceding cover date. Send order and remittance to Computer Mart, POPULAR ELECTRONICS. 725-4216. 1 Park Ave., N.Y., N.Y. 10016. Direct inquiries to (212)

Computer Mart

LOWEST POSSIBLE PRICES

TRS-80

BEST POSSIBLE WARRANTY

DISCOUNT COMPUTERS

-

-

-4qt

model Ill

CALL US LAST

iTh

$

1

for

the LOWEST

The popular VP Series Z80 Industrial Quality Computer is now available unassembled for OEM's, Clubs etc.. Assemble as many as you

161K

839

want for a one time fee. Wirewrap or PC board versions. CP/M 2.2 and 1K EPROM monitor runs all CP/M Software. Specifications: Z80 CPU, 3 RS232 Serial Ports, 4 Counters-Timers, 4 Channel DMA, Soft Sectored Disk Controller, Video Controller (80X25), 8K EPROM, 64K-256 RAM, Clock Calendar chip, Printer Port, Keyboard Port, over 64 Parellel I/O lines, or board regulators. Expansion area and Expansion Interface connector. The one board computer that does it all!

-

price'

color computer 4K Ill."

$310

918-825-4844 will

-

be worth the call!

it

:

A4 t .1 AMERICAN .4%.-

Small BusiNiss

1-800-343-8124

can TOLL FREE

Littleton, MA 01460 Write for your free catalog. 'RS

80

s

a

61

recosieren trademark

cinCLE NO

CIRCLE NO 124 ON FREE INFORMATION CARD

486

7

(314) 961-2229 Contact: KENNETH TAGGART.

3193

i

co

CIRCLE NO, 126 ON FREE INFORMATION CARD

125 ON FREE INFORMATION CARD

Sinclair

514" Floppy Disk Drives

NEC:

TANDON CDC 2

COMMODORE VIC

$219.95.

Adds, Hazeltine. Televideo

Calculators

on

-

TOLL FREE

8 Sharp

Sony

Scotch Data Diskettes 8 VCR Tapes

Mail Order: FUTRA COMPANY

CIRCLE NO 127 ON FREE INFORMATION

I

654tPu. SgStaivS

game, swap sides. and more (165) INVADERS! Ten levels of play. II6K) STARTREK Trek across the galaxy (16K) ADVENTURE:Damsel and Me Beast (16K) 1K PROGRAM PACK. 8 compact. entertaining programs 1131( PROGRAM PACK. Four entertaining programs 10 EXCITING ZX81 PROGRAMS

Books 30 Programs or rile Z)(81(1KI Understanding Your ZX81 ROM laill ROM Disassembly Part A Full replacement warranty all rapes WrJle tor ow FREE SOFTWARE CATALOGUE

St 50 per order

LEO ELECTRONICS, INC.

NOW AVAILABLE

SI4.95 $19 95 $14 C5 iO, 7X51

nand.°

UV EPROM ERASER

/III

WHY PAY MORE? SAVE MONEY!

Two-pass assembly. wlorward references

Manufacturer's complete instruction set

LOWEST PRICES ON PARTS!

Long error messages. free-format input

ERASES ALL UV ERASABLE EFR9OMS427012719, BMA Mc COIGN FIFTEEN MINUTES ERASE TIME ERASES OVER FIFTEEN EPROMS AT A TIME

Written in 1966 ANSI standard FORTRAN IV

"industrial" Macroassemblers also feature macros, conditional

Pr

REGULATORS

EPROMS

assembly, relocatable object code

"INDUSTRIAL"

"HOBBYIST'

MACROASSEMBLERS

ASSEMBLERS

$400.00 350 00 500.00

$200 00 150.00

2708 2716

2.60 4.00

2716-11350mal TMS 2716

2732 2532

6.50 6.00 12 00

1200

7805 7812 7815 7905 7912 7915

75

.75

LAMP LWE 77C0 NOMA INCUSTRIAL MOOG. 18650 INDuSTIRAL mODEL WITH TIMER & SAFETY iNTERLCCE swiTCH $97 50 (Ruggd MA* enclocaa wen bottom draw.

75 .85 .85 85

250.00

Prices include source code on tape and in printed form, User's Manual. shipping (USA), and program support. All programs shipped from stock.

NOS SNIGE

THE BEST


DOM

COUPU113 AVNLY31.1

ny/7,

WI.* Ma Of

AS-132 Rart

am

PRICE

ASSEMBLED TESTED as HOUR BURNis

0

MICROPROCESSORS

RAMS 41 161200es)

4116(150ns) 2114(200ns)

8/ 13.00 8/16.00 8718.00

271e EPROMS

SO

250 na 54.96

INTELLIGENT DEVICES, Inc. P.O. Box 163

DIRECT FROM FACTORY

CIRCLE NO 130 ON FREE INFORMATION CARD

#

8080A 8085A

700

R5.232 INTELLIGENT EPROM PROGRAMMER...x.419.w Pmgrams. 2716, 2518, 2532, 2732, 8748, 8740 $3.05 B' Ae41ISTAT1C FOAM 4'

only CaltfigrOla Residents add 6% Sales Tax.

SHIPPING( Add 82 00 for Ground $5 00 for Air ALL MAJOR MANUFACTURERS ALL PARTS 100% GUARANTEED CIRCLE NO

131 ON

Motto

SS60

MOO

CPU CARD:

PHONE ORDERS

TERMS: Check. Visa. Mastercard Call tor COD I) S FLrOds

Colorado 80435

WARRAH,

50 300

1MHZ 8149.00

WE ACCEPT VISA MASTERCARD C

Ill

DAY

5

Z-80A-CPU

tomorrow!

(303)488-0112

$389.00

FOR THE SSSO AND 5.100 BUS

SPECIAL ON PREPAID ORDERS: Same-day EXPRESS MAIL snipping. for no extra charge. Call today-your program will arrive

IDI

99.95 99)95

11415

CIRCLE NO 129 ON FREE INFORMATION CARD

8921 S. Sepulveda *208 Los Angeles, CA 90045 (213) 641-3101 (800) 421-2418

WRITTEN IN FORTRAN IV

S9.95 89.95

E1415

GLaDST011E

CIRCLE NO. 128 ON FREE INFORMATION CARD

CROSS ASSEMBLERS

824.95

Gladstone Electtonics 901 FOWmann Blvd Buf tat° NY 14203 TeMpRone Orders i716, 8490735 VISA/MC No C O OS Picas. Mad Orders Send check money order Visa or MC number

923 Longfellow Street Wichita, KS 67207

AR()

each of the two rkftersnt cross-assembie,s followIng microprocessors 6800 6801 6805 6809 68000 8080,85 6502 1802

$9.95 $9.95 ZX CHESS! Your chose of 7 levels AI play. whole or black, set de any Position to be analyzed, change levels of play during a

I

(800) 421-5006

20695 S. Western Ave #124, Torrance, CA 90501 TWX 910 349-6211 AGENFTRA TRNC

6809 or 6502 Other 8-bit 16-bit

MULTIFIEE Data Storage System A versatile multi-purpose hi ing system for 16K 2)(131 MenuOnyen The number. size and heading of Ides ate oserdefinable Files may be created modified, replaced, and searched, and are protected by a security lock Output to ZX printer is provided MULTIFILE supplied on cassette with three blank cassettes tor data storage, and packed in an at tractiye permanent storage case

ZXASMactone Code Assembler 06K) ZXDB Machine Code Disassembler/Debugger (16K)

P.O. Box 4380-P, Torrance, CA 90510

(Target Machine(s))

cassette.

Supplied with extensive documentation describing applica lions lor both business and personal use $29.95

MC/VISA or C.O.D. with certified check or money order. Kansas residents add 3% sales tax. Plus shipping For info call: 316-683-9225 316-685-9445

Video Recorders

,

Software

$214.95 ea.'

800-824-7888 all states except CA 800-852-7777 for CA residents. Ask for Operator #99.

Terminals

(213) 328-8951 Retail: OMC

ZX13'1 .

CALL NOW

RCA VP-3501 Videotex Data Terminal CALL $

&

-

IVIodel 9409

or more

.

$CALL

Mitsubishi (MGA), RCA

ect I(3M Plug all Model TM 100-1

$119.9 ,, Zenith Monitor We also stock TM-100-2.s. the TM 602S 603S and the 603E Winchester Drives

APPLE, ALTOS, HP á XEROX

H P

DATA WORLD INCORPORATED 8061 Watson Road St. Louis, MO 63119

245A Great Goad

COMPUTERS

118 S. MILL ST. PRYOR, OK. 74361

SUPER BARGAIN CP/M SINGLE BOARD COMPUTER - $390.00

FREE INFOR

A

I

N

CARD

TWO

51041668406

2MHZ

0 D CHECKS

(305) 776.5870

Engineering HotLine IM61 FTMFMT

LOGICAL DEVICES INC. .11 To

A OAKLAND PARK BLVD ADP WO

ROM..

co

>200

LAUDERDALE C

0

CHARGES

FLORIDA

NOW! 176K TOTAL RAM For the '89 II Compatible Banks "Invisible Disk" CP /M Software Included 3 MP /M

$595.00 MAGNOLIA Only

DISKETTES (CASSETTES Error -Free 51/4-inch Diskettes (MD5) single- sided, soft sector, single or double density, reinforced hub. Item

Qty 10

Qty 50

MD -5

$25.00

$110.00

C -10 C -20 C -60 C -90

$

SEATTLE,

Il' are registered trademarks of Digital Research, Pacific Grove. CA

475 Ellis St., Mt. View, (415) 968-1604

Oliver Advanced Engineering, Inc. 676 W. Wilson Ave., Glendale, CA 91203 (213) 240 -0080 or Telex 194773 PP SERIES PROGRAMMERS

CA 94043

CIRCLE NO 133 ON FREE INFORMATION CARD

CIRCLE NO 135 ON FREE INFORMATION CARD

CIRCLE NO. 134 ON FREE INFORMATION CARD

Professional

Save On -80TM

OAE's PP- Series EPROM Programmers plug directly into any vacant EPROM socket and allow you to transfer data directly from RAM to EPROMs. No additional power supplies are required. All timing & control sequences are handled by the programmer. Each un t indudes internal DC to DC switching regu ator. ZIF socket and 4 ft. ribbon cable terminated with a 24 pin plug. Programmers are available for all EPROMs from 2708's thru 2532's.

MICROSETTE

W/A 98119

CP /M. & MP /M

TRS

15.00 in Continental USA CA Customers add taxes

[800] 426-2841

(206) 285 -7266

32.50 39.0() 50.00 70.00

$

UPS SHIPPING INCLUDED

MICROSYSTEMS 2264 -15th AVE W

7.50 9.00 11.50

REAL ESTATE SOFTWARE

Computers

Im APPLE. TRS-aO

ONE STOP FOR

CPM SYSTEMS

SINCLAIR

PROPERTY MANAGEMENT SYSTEM: 3375 tenant History

Operating] Samt

Late Rent Report

Building Reports

Vacancy Report

LIMON's Report

Income Report

las

Prints Crimes

Returned Checks

Prints Receipts

PROPERTY LISTINGS, LISTINGS

--

ZX81

Expense Report

Auto Late Charge

SOFTWARE

SUS

WRITE FOR FREE CATALOG AND FREE PROGRAM LISTING OF MASTERMIND

Max /Min Pica

SCREEN BY

Unes /Ione'Ciry

/Listing 10001H1ing/Disk

Max Price /income

Listing Memo Field

Min Cashslow

22 Items

For the best deals on TRS-80 Computers, we have SPECIAL DISCOUNTS, FREE SHIP-

PING and

a

TOLL FREE ORDER NUMBER.

REAL ESTATE ANALYSIS MODULES: S50 /Module

Pan American

Electronics

Mission, TX 78572 Telex Number 767339 Toll Free Order Number 8001531.7466 Texas & Principal Number 512/581.2766 TM - Trademark of Tandy Corporation

Max Rice /So Foot

Defined Exchange

Hems Purchase

Tax

income Prop Analysis

APR Loan

Properly Sates Construction Cost /Prole

Loan Amortization

WORD PROCESSOR

Analysis

SOFTSrYNI INC.

Depreciation/ACAS Analysis

MAGIC WAND: 5265

PQ Bouc 48Q Minay Hill Station,

1117 Conway

At

Mtwara

Computer Sloes Evert/where or

EP-any

Cal

orner

OO

Residents um

New luit, N.Y 10156 (212) 685 -2080

xnetl

t'.

Sau

Tas

1213' í72-9419

Suite E. 1116 -815 Street Manhanan Baarh. CA 90266

CIRCLE NO 137 ON FREE INFORMATION CARD

SUPER SALE

TRS -80

EPROM's 1

-7

8up

CIRCLE NO 138 ON FREE INFORMATION CARL

50 up

*MICROCOMPUTER*

BUSINESS SOFTWARE

2716 (450nS, 5V) $3.95$3.55 CALL 2732 (450nS, 5V) 7.85 6.95 CALL

2K x 8

C

MOS RAM 1

6116P -3

(1

50nS)

-7

8up

50 up

$7.50$7.20 CALL

16K RAM EXPANSION KIT For TRS -80 Model Ill Set of 8 pieces UPD41 6C -2 (200nS)

Model Il 64k_ Model Ill 16k. Model Ill 48k 2 Drives RS232

EPSON Printers

IN

Discount Prices lull line of Radio Shack 8 TCS Custom Computers and Accessories. Call for catalog

$4.20 $7.20

SUNTRON/CS CO ,

INC

12621 CRENSHAW BOULEVARD

HAWTHORNE. CALIFORNIA 90250

1213) 644 -1149 SIO PH

52 At

,:

,,,.. ...... OUTSIDE CALIFORNIA TOLL FREE .,

1- 800 -421-5775 noi LISA

SCALL

on

ADC0809 (Analog /Digital Counter) 8 bit /8 channel multiplexer EPROM 2716 -1 (350nS, 5V)

.

MEDICAL MGMT... DENTAL MGMT... INSURANCE AGENT LEGAL BILLING PROPERTY MGMT.. AND MUCH MORE

5308 5459

All printers and accessories In stock.

$12.95

MISC

s70RE Nouns CALIFORNIA

5825 $2069

Color Computer 4k Level I Color Computer 16k Extended Basic

Data furnished with ourchase on request

v

53288

Mastercard

Check or M 0

Texas P

!

Computer Systems

Box 1327

Arlington. Texas 76004 -1327

TOLL FREE

UNIVAIR INTERNATIONAL

800 -433 -5184

10327 Lambert International Airport

Texas Residents 817-274 -5625

ST. LOUIS, MISSOURI U.S.A.

PARl4ENT

Money order, cash ers check or certiiled check. Prices reflect 3 °in cash discount. Call 'or VISA and Mastercard paces

63145

(314) 425 -1099 a

CIRCLE NO. 139 ON FREE INFORMATION CARD

CIRCLE NO 140 ON FREE INFORMATION CARD

Electronics Classified CLASSIFIED RATES: Per Word, 15 Word Minimum. COMMERCIAL: $3.50. EXPAND-AD`: $5.25. DISPLAY: 1" x 21/é', $425.00. 2" x 21/4', $850.00. 3" x 21/á', $1,275.00. Ads set in all bold type 1ú 20% premium. Ads set with background screen at 25% premium. GENERAL INFORMATION: Frequency rates and prepayment discounts available. Payment must accompany order except credit card -Am. Ex., Diners, MC, VISA (include exp. date) accredited ad agency insertions. Copy subject to publisher's approval; must be typewritten or printed. First word set in caps. Advertisers using P.O. Boxes MUST supply permanent address and telephone number. Orders not acknowledged. They will appear in next available issue after receipt. Closing date: 1st of the 2nd month preceding cover date (e.g., Mar. issue closes Jan. 1). Send order & remittance to: Classified Advertising, Popular Electronics Magazine, 1 Park Avenue, New York, NY 10016. Direct inquiries to Rose Lynch,

-or

(212) 725-7686.

FOR SALE GOVERNMENT and industrial surplus receivers, transmitters, snooperscopes, electronic parts, Picture Catalog 25 cents. Meshna, Nahant, Mass. 01908. ELECTRONIC PARTS, semiconductors, kits. FREE FLYER. Large catalog $1.00 deposit. BIGELOW ELECTRONICS, Bluffton, Ohio 45817. SAVE UP TO 50% on name brand test equipment. Free catalog and price list. Salen Electronics, Box 82, Skokie, IL 60077.

TELETYPE EQUIPMENT: Copy Military, Press, Weather, Amateur, Commercial Transmissions. Catalog $1.00. WEATHER -MAP RECORDERS: Copy Satellite Photographs, National -Local Weather Maps. Learn How! $1.00. Atlantic Sales, 3730 Nautilus Ave., Brooklyn, NY 11224. Phone: (212) 372 -0349.

BUILD AND SAVE. TV EARTH STATION. DETECTIVE ELECTRONICS. Video Recorders, Color Cameras, advanced Telephone Projects. BROADCAST Electronics. 50 page color catalog of unusual electronic projects AIR MAILED $3.00; with 3 hour audio cassette dramatization of our catalog $5.00. Don Britton Enterprises, PO Drawer G, Waikiki, Hawaii 96815.

Satellite TV FOR THE HOME Sick of Network TV?

RECONDITIONED TEST EQUIPMENT $1.00 for catalog. WALTER'S TEST EQUIPMENT, 2697 Nickel, San Pablo, CA 94806, (415) 758-1050. NEW ELECTRONIC PARTS. Continuously stocked. Stamp brings catalog. Daytapro Electronics, 3029 N. Wilshire Ln., Arlington Hts., IL 60004.

and backyard installations, we wrote the book. Constantly upHardware! dated, our 94 Page technical information book and catalog gives you all the facts. Inexpensive dishes, feeds, telemetry software, kits and more. Recommended reading by NASA, The Office of Consumer Affairs and quality companies like Rockwell /Collins. Send $7.95 today! CALL e 24 -hrs. C.O.D. Hotline (305) 339-7600 ®

SPACECOAST RESEARCH CORPORATION

0. Box 442 -A, Altamonte Spgs, FL 32701

RF POWER TRANSISTOR - TUBE CATALOG FREE. MRF453/MRF455A/SK1451 - $14.00; MRF454 /SRF2072/ MRF2769- $17.00; MRF245/MRF247 - $27.00; 2N4048 $6.20; Exclusive Repair Center for PALOMAR PRIDE, etc. Westcom, 1320 Grand, San Marcos, CA 92069. (714) 7440728. Latest microatrlp model of fhe "ongmalLT13 Down Converter with Preamp 16 dBi Slotted Antenna Deluxe Power Supply Kit All Coaxial Cables Included 2000 2600 MHz Tuning Range

D Buy

Gov't Surplus SAV E To

85'1,

Each

$19.95 Dty

eiu

Avail

MBA

MII

(704) 735 -3943.

size Ice

From offshore oil rigs, data links to hotels

Plans and Concepts SUBSCRIPTION TV MANUAL $14 95 Theory. Schematics. Etc. KITS AVAILABLE INFORMATION PACKAGE $2.00 Send Check or MO. Add 5 °' Shipping CA Residents Add Tax. ABET. P.O. Box 26601 -PE. San Francisco, CA 94126

We Manufacture

PRINTED CIRCUIT BOARDS, your artwork. Quick delivery. Reasonable. Atlas Circuits, Box 892, Lincolnton, NC 28092.

Record telephone conversations in your office or home. Connects between any cassette or tape recorder and your telephone or telephone LINE. Starts automatically when phone is answered. Records both sides of phone conversation. Stops recorder when phone is hung up. This device is not an answering service

MICROWAVE TV ANTENNA $169.95 18 Dish Type Antenna. Probe Mounted Down Converter. 6 Month Warranty MICROWAVE TV MANUAL $16.25 .

sell Information!

ELECTRONIC CATALOG. Over 4,500 items. Parts, & components. Everything needed by the hobbyist or technician. $2.00 postage & handling (United States Only), refundable with first $15.00 order. T & M Electronics, 472 East Main St., Patchogue, NY 11772. (516) 289 -2520.

Telephone Listening Device

Global TV Electronics. P.O. Box 219 -E. Maitland. FL 32751

We don't just

P

LAB - TRONICS, INC. P O Box 171

Rogers. MN 55374

612 -428 -4226

Send 606 For Big Bargain Catalog 1000'. Of Bargains; surplus, r Brand Nam. N. aquipnr.nl awoi[s rau coron COMPalssas rInpunI[S %MIMS rolle POMts [LIMON. SUOlTING 11.1511UMtxn nul illUr4l 11

turf

Nr0110U11C5

SURPLUS CENTER

ALaS aM

nMK(UUn

DECODE Morse, RTTY, and ASCII

UNSCRAMBLE CODED MESSAGES from police, fire

and medical channels. Also telephone recording

adaptor. Same day service. Satisfaction guaranteed. Don Nobles Electronics, Inc. Route 7, Box 257 -A, Hot Springs, AR 71901. (501) 623 -6027. RF

MODULATORS for SATELLITE TELEVISION, MI-

Also monitors, cameras, kits. FREE CATALOG. Phone (402) 987 -3771. Dealers Welcomed. ATV RESEARCH, 13 -P Broadway, Dakota City, NE 68731. CROCOMPUTERS CCTV.

BUYER BEWARE - Consumer guide to SATELLITE TELEVISION - $3. Ghostfighters, Route 2, Box 136B, Stevensville, Montana 59870. LOW, LOW COMPONENT PRICES! Ask for free flyer. Write: EEP, 11 Revere Place, Tappan, NY 10983.

Inrnrorr,

Be an ELECTRICIAN

ra4UM n1

TOOL

On TOOLS

Box 152709-11

KUM PUMPS

TTf

Lincoln, Nebraska Zip Code 68501

/// .

7

Skilled Electricians Average Over $11 an Hour Learn at home in spare time with no previous experience. We encourage you to check on the job market in your area and send for employment succew figures of our graduates. Learn installation, maintenance, construction, lighting, beating, air conditioning applications. Seed kw

13830.

10 times more powerful than other mics. Transmits up to 'h mile to any FM radio. Easy to assemble kit. 15V battery (not incl.)

Call (305) 725 -1000 or send $19.95. $1.00 shipping per non to USI Corp., P.O.Box PE-2052, MNboume,FL 32901. COD's accept. For catalog of transmitters,vdce scramblers and other specialty items, enclose $2.00 to USI Corp.

ROBOT KITS, PARTS, MATERIALS, BOOKS. Send $3 for subscription to catalog and newsletter. ROBOT MART, 19 West 34th St., New York, NY 10001.

SATELLITE TELEVISION ... HOWARD /COLEMAN boards to build your own receiver. For more information write .. ROBERT COLEMAN, Rt. 3, Box 58 -APE, Travelers Rest, S.C. 29690. .

UHF GATED PULSE SUPPRESSED KIT $39.00. UHF SINEWAVE SUPPRESSED KIT, $37.00. Both include parts, manual, and Etched Board. Manual only $4.60. Catalog $2.00. J &W Electronics, P.O. Box 61, Cumberland, RI 02864. 104

FIE

FACTS.

Electrician's EeMN, DSILPDO ICS Center, Scranton, PA 18515

SATELLITE TELEVISION INFORMATION $4. Build or buy your Earth Station. Satellite Television, RD 3, Oxford, NY

Wireless Mic

signals from air-

waves with new CODE *STAR. LED readout or connect your computer/printer. Keyboard, other items also available. Kits or assembled. MICROCRAFT, Box 513PE, Thiensville, WI 53092. (414) 241 -8144.

e

Powerful

1131 CHANNELS

New antenna construction plans plus big 8 x 11 book loaded with aiming info. kits. LNAS and receivers at wholesale prices. Far better than cable TV! Enjoy crystal clear reception. Send $9.95 today. Add $2.00 for 1st class (air mail) or call our 24 hr. COD order line (305)862 -5068 Now.

Our receiver lets you get over 75 channels of television directly from earth orbiting cable TV satellites!: HBO. Showtime, super stations, sports and movies worldwide.

POLICE/FIRE SCANNERS, crystals, antennas, CBs, Radar Detectors. HPR, Box 19224, Denver, CO 80219.

PRINTED CIRCUIT supplies, chemicals, tools, artwork, plating solutions. Major credit cards. Catalog $2.00, refundable. CIRCOLEX, Box 198, Marcy, NY 13403.

SATELLITE TV FANTASTIC 80

PAY TV ENCODING /DECODING.

72

Latest systems cov-

FREE CATALOG 99 cent kits. Parts. Bargains Galore! ALL KIT, 434 West 4th St., West Islip, New York 11795.

ered, $8.95 G.A.M. Engineering, 706 Akron Blvd,

FREE KIT CATALOG contains test equipment. Phone 415447 -3433. DAGE SCIENTIFIC INSTRUMENTS. Box 1054P, Livermore, CA 94550.

SATELLITE TV LOW NOISE AMPLIFIER, Build for under $100! Satisfaction guaranteed. Detailed instruction manual

-

Surf $19.95, Wind $19.95, SOUND SYNTHESIZER KITS Wind Chimes $24.95, Musical Accessories many more. Catalog free. PAIA Electronics, Box J14359, Oklahoma City, OK 73114.

RESISTORS, 1/4W, W5 %C.F. 3cea., 1% Metal films. NO MINIMUMS, Cabinet Assortments, Quantity Discounts. Details from: JR INDUSTRIES, 5834 -E, Swancreek, Toledo, OH 43614.

Kent, OH 44240.

$7.00. XANDI, Box 25647, Dept 22A, Tempe, AZ 85282.

CABLE TV CONVERTERS & EQUIPMENT. Plans and

parts. Build or buy. For more information send $2.00:

C & D

ELECTRONICS INC., P.O. Box 21, Jeni-

1

VARIETY ELECTRONIC SURPLUS parts and pieces. Monthly picture flyer. Send $2.00 for 6 issues. Star -Tronics, P.O. Box 683, McMinnville, OR 97128.

son, MI 49428. MICROWAVE TV DOWNCONVERTERS, Downconverter board, power supply board, Antenna Cookbook, with detailed plans, $20.00. Downconverter parts $15.00, power supply parts $15.00. Micro Engineering, P.O. Box 17231, Minneapolis, MN 55417. POPULAR ELECTRONICS

FOIL COPYGUARD kit. VHSZeta compatible. Professional results. Easy assembly. Kit includes PC board, components and instruction manual. 14-day money -back guarantee $52.95 ppd. CA add $3.00. VIDEO TECHNICA, Box 2108, Downey, CA 90242.

PCB 15s sq -in FREE DRILLING. SATISFACTION GUARANTEED. International Enterprise. 6452 Hazel Circle, Simi Valley, CA 93063.

EXPERIMENTAL FREQUENCY CONTROL MODULE. Finest available in either Sine Wave or Gated Pulse. Kits, plans or factory built. Information package $2.00 refundable. LEE TRONIX, P.O. Box 253, Taylor, MI 48180. PRINTED CIRCUITS manufactured from your artwork. PROTOTYPES - .35e; .35e- square inch single side; .50e-double side. le per hole drilling. FREE tinplating. For QUANTITY orders CALL for lowest prices. $10. minimum. INTERNATIONAL CIRCUITS, Box 496, 210 S. Main, Crown Point, IN 46307. (219) 663-1295. SUBSCRIPTION TV. Sync pulse suppressed systems. Theory/circuits. Educational manual, $9.95. WORKSHOP, Box 393 -PE1C, Bethpage, NY 11714.

GATED PULSE KIT. Watch uninterrupted Movies, Sports on T.V. Heavy Duty factory built units Available. Send $2.00 for price catalog: MELI -TRON Div., Box 250, Trenton, MI 48183. SATELLITE T.V. New low cost GasFets. LNA's. books, data sheets, satellite locating equipment. Catalog $5.00. Elite Electronics, RR1 St. George, Ontario, Canada NOE 1NO. U.S. Inquiries.

Quality Microwave TV Systems to 2.6 GHz Ant. 34 db Gain $149.95 Complete System as pictured Down Converter Probe 64.95 Mntd., Assembled 8 Tested Power Supply (12V to 16V) Assembled 8 Tented 59.95 2.1

Data Into (Plans)

9.95

Phillips -Tech Electronics Box 33205. Phoenix, AZ 85067 (602) 274-2885 P.O. 6

MONTH WARRANTY

MasterCard- Visa-C

PARTS 8 LABIR

00/s

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4904. SHORTWAVE LISTENERS! Free catalog. High quality SWL equipment! RADIO WEST, 3417 Purer Rd., Escondido, CA 92025. (714) 741 -2891. The Only all SWL store in the Known World. 10' PARABOLIC Dishes, Satellite Television Antennas. Complete Package. Highest quality, priced only $749.97. Call or S.A.S.E.: Micro-wave Electronics, 1168 Oakmont Drive, Temperance, MI 48182. (419) 729 -0548. Dealers Wanted.

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FM STEREO TRANSMITTER KIT. Range up to 1/3 mile, broadcast quality, 30 db separation, 300 my audio input sensitivity. Tunes 88 -108 Mhz, highly stable, 50 ohm out. Requires + -15V. Complete kit 89.95. Commercial quality AM TRANSMITTERS also available. Free info. STELLATRON, 4942 Whitsett-205, N. Hollywood, CA 91607. 213/506-0415.

PROFESSIONAL LIMITER- COMPRESSOR -EXPANDER KITS. Pro specs and features, balanced input, adjustable threshold, slope (1:1 to 100:1). attack and release. Models from $79 and up. Rack mounting available. Free Info. STELLATRON, 4942, Whitsett-205, N. Hollywood, CA 91607. MINI FM MIC Transmit Compact sve only 2 xt *' to FM rad,n 88 108 MHz Exceptional audho quality Transmits stable signal up t0 900 II Complete kil incl case battery 8 instructions Only $13 95 Assembled $1e 95 Add $ t 55 58H ea Send tee stamp for brochure S.E. Corp.. Boa 16969-P Temple Terrace. Fl 33687

UNIQUE TV CIRCUIT plugs between UHF and VHF tuners on tube or solid state sets. Plans $3.95. Drilled etched printed circuit boards $23.00. HELICO ANTENNA receives multi polarized signals. Plans $3.95. Antenna Kit $19.95. Information $2.00. HELICO, P.O. Box 304, Bridgewater, MA 02324.

ROBOTS, eproms, PC Boards, games, tools, more. Catalog $2. Cosmic Enterprises, Box 9045, Stockton, CA 95208. UNIQUE APPROACH, Highest gain microwave T.V. reception. Temperature stable. Kits $39.95, PS Less Xformer $14.95. D R DESIGN, Box 401382, Garland, TX 75040. 105

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PERSONALS MAKE FRIENDS WORLDWIDE through international correspondence, illustrated brochure free. Hermes-Verlag, Box 110660/Z, D -1000 Berlin 11, W. Germany. CORRESPONDENCE FOR FRIENDSHIP IN PHILIPPINES, MALAYSIA. Free information. AAWS -(PE), Box 2777, Orcutt, California 93455-0777.

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GOVERNMENT SURPLUS GOVERNMENT SURPLUS ELECTRONICS! JEEPS, CARS $30.00! 800,000 Items! Complete Information Your Area. LARGEST OFFICIAL DIRECTORY. $2.00. SURPLUS, A148, 4620 Wisconsin Northwest, Washington, DC 20016. SURPLUS JEEPS, CARS AND TRUCKS AVAILABLE. Many sell for under $200. Call: 312- 742 -1143, Ext. 4649, for information on how to purchase.

WANTED GOLD, Silver, Platinum, Mercury, Tantalum wanted. Highest prices paid by refinery. Ores assayed. Free circular. Mercury Terminal, Box 191, Norwood, MA 02062. ELECTRONIC STORE NEEDS UNUSUAL games, gadgets, and gizmos to sell. SUPPLIERS contact: Dick Day, 402 -3791440, P.O. Box 1187, Norfolk, Nebraska 68701.

+ P., Electronics, Flight Schools. 11 months. All work on certified aircraft. AeroTechnicians, Box 7PE, Rexburg, ID 83440, (208) 356-4446.

TUBES: "Oldies ", Latest. Supplies, components, schematics. Catalog Free (stamp appreciated). Steinmetz, 7519 -PE Maplewood, Hammond, Ind. 46324.

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MECHANICALLY INCLINED individuals desiring ownership of Small Electronics Manufacturing Business without investment. Write: BUSINESSES, 92 -K7 Brighton 11th, Brooklyn, New York 11235. ERASE DEBTS with little-known law- create wealth!! Details FREE Blueprints, No. EE7, LaGrangeville, NY 12540.

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I HAVE MADE A FORTUNE in Mail Order, selling information. Let me show you how. Write: Kash, PE -701, Box 31051, Indianapolis, IN 46241.

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PICTURE TUBE REBUILDING equipment new and used. ATOLL TELEVISION, 6425 Irving Park, Chicago, Illinois 60634. MAKE MONEY SELLING ELECTRONICS. Wholesale dealer catalog $5. (redeemable). ETCO, Dept. 532, Box 840, Champlain, NY 12919. CASH IN ON EXPLODING HOME COMPUTER MARKET. Become a distributor. Investment of only $536 includes TEXAS INSTRUMENTS home computer. Start building your business now! FREE details. Send S.A.S.E.; COMPUTER -P, 24431 Los Serranos, Laguna Niguel, CA 92677.

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ONE MAN CRT FACTORY. T.V.'s, Business machines, Monitors, Scopes, VDT's. $3.00 rebuilding nets $100 -$500 each tube. Higher profits overseas. New /used. FACTORY, 1909 Louise. Crystal Lake, IL 60014. (815) 459 -0666.

INSTRUCTION

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D &A EQUIPMENT REPAIRED: Virginia Sabala, D &A's head technician 15 years, is now operating a parts and repair service. Communications Unlimited, 1217 Ave C, Scottsbluff, NE

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ELECTRONICS CAREERS. Nationwide shortage of Engineers and Technicians, High pay. Solid future. $2.00 for informatilin on how to enter this exciting field. Professor Rush, Box 6155, Kansas City, MO 64110.

1982 PHOTOGRAPHY DIRECTORY & BUYING GUIDE IProduct listings fou virtual even canera and piece

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RECORDS TAPES! Discounts to 73% All labels; no purchase obligations; newsletter; discount dividend certificates. 100% guarantees. Free details. Discount Music Club, 650 Main St., PO Box 2000, Dept. 5 -0782, New Rochelle, NY 10801.

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ELECONIC5i D R

Personal Electronics News

CHILDRENS' TV VIEWING can be controlled with a new device from General Electric called "Channel Block -Out ". It allows parents to defeat the reception of undesired channels for a period of up to 12 hours by keying in a customer- selected four -digit code, together with the

channel numers. A channel can be replaced at any time by re- keying the code number. "Channel Block -Out" is available on 12 different GE receivers for 1983.

Ford Motor Company uses the capabilities of the computer controlled Message Center that is standard equipment in the 1982 Lincoln Continental. Unlike a typical hand-held phone, the new system is said to enable a vehicle occupant to place calls by dialing numbers on the Message Center's keyboard, speaking into a microphone concealed in the driver's sun visor. The other party is heard through the rear speakers of the car's audio system. While a call is being made or received, the regular functions of the Message Center (display of time, distance, speed, and fuel economy) are unaffected. Called Commcar, the new technology is being displayed at major 1982 auto shows, though it is not currently planned for production. AN AUTOMOBILE PHONE from

A ONE -INCH SQUARE PROM

(Programmable

that contains all the information on mail rates found in a U.S. Postal Service Directory is being manufactured by Pitney Bowes. Designed for installation in Pitney ROM)

Bowes postage meters, it can be quickly replaced should postage rates change. Users of the PROM are thus spared the tedium of cross referencing shipping weights against mailing costs, and can readily accommodate their operation to the wiles of the Post Office. PRESTEL COMES TO KNOXVILLE in the first U.S. demonstraton of the British videotex system.

The World's Fair pilot project, involving 200 Prestel terminals, is sponsored by Financial Interstate Services and Logica, Inc., which will market the Prestel terminals in cooperation with British Telecom and GEC Computer, Ltd. The terminals have been placed on the site of the World's Fair and in adjacent hotels, banks, and transportation terminals. A special database has been developed for the project that includes event schedules and shopping information as well as banking services. CELLULAR RADIO is emerging as a hot prospect for investors now that a group of radio common carriers (RCC) has formed a consortium to acquire frequency allocations. The new firm, called Cellular Systems, Inc. (CSI), is an association of 12 RCCs in the Northeast. The stated goal of CSI is to setup a cellular radio system in every major market. For its part, the FCC is granting two licenses in each market: one for the Bell System; the other is the slot CSI hopes to fill. Under the CSI plan, each RCC would lease equipment and share in the profit. Eventually,

there could be a national organization, with all cellular systems being compatible within the CSI network.

COMPUTER POWER will be expanded by a factor of six to twelve, according to Cray Research, Inc. ( Mendota Hts., MN). Now in the development stage, the CRAY -2 computer will have a 32- million -word memory, and a CPU cycle time (clock speed) of four nanoseconds. This capability represents a considerable improvement over the CRAY -1, now the most powerful

computer available. Cray said the advance was made possible by applying liquid immersion technology to remove heat from the system, thereby permitting dense circuit packing in three- dimensional modules. Close packing is important in supercomputers,because at switching speeds of a few nanoseconds, even a signal moving at the speed of light is sluggish over the length of an average wire. Accordingly, the longest wire in the CRAY -2 will be 16" ( compared to four feet in the CRAY -1). 108

POPULAR ELECTRONICS

How to turn your HP- 41 into a handheld computer. -..

Introducing the Hewlett- Packard Interface hoop. Starting today, your HP -41C or HP41CV can be more than just a great little calculator It's a great little computer, capable of cantrol:ing a quicklyexpanJing family Of peripherals. The new Hewitt- Packard Interface Loop (HP -IL) makes it all possible. HP -Ir. is an easy-to-use, low-cost interlacing system, specifically designed for battery-

operable devices The Interface Module and

Peripherals. At the heart

of the system is the Interface Module, which plugs into any one of four HP-41 ports. You can control up *_c 31) peripherals, using only one port in your HP -41 calculator_ One of he key I3P -IL peripherals is the new Digital Cassette HP-IL Drive. Tv- battery-

incdhle 131,000 byt

to

ma,s tremor: Another work -saving 1-IP -11. r riliiv.ral is the new battery ( )pti-able Thermal Printer PI() CV with enhanced format,, options and graphi':s. This is just the beginr_ ing. There a:e many more HP -Ii products tin the way And they're t II designed to provide the vertility and adaptabiiiyyou expect from HP You see, Elm-Lit-Packard is writ :al to a very hig ikea: small devices talking to each other, giving you big ,-stem capabilities - at small system plc_ ces! For deter is and the address of your nearest dealer; CALL TOLL FREE: 800 547-3400, Dept 2541, except HEwaiii Alaska. In Oregon, call 758-101C. or write Hewlett - Packard Corvallis, OR _47330, Dept. 254 1. iT[users(503) 75f+ -5566. -

71

c

6111

3.

When perJormarar n: ust be measured ay resats.

operable device provides 311 CIRC-E

HEWLETT PACKARD NI 3 JN FFEE

INFORMATId. CARD

Report Manager and the PC -8000 Personal Computer: An unprecedented three dimensions of management information. All those legendary electronic spread sheets that have been making other kinds of personal computers so useful for managers are now literally flat by comparison to the remarkable combination of Report Manager'" and the NEC PC -8000 Personal Computer. Here you get the power and versatility of an electronic book, not a mere electronic page. An axis of depthjoins the horizontal and vertical -so you can, for instance, track a number of different profit centers over the same period of time ... or follow actual performance

against projections by both department and time frame. The fact is that any sort of planning work you find useful in two dimensions, you will find that much more useful in three. The program allows you to see four separate "slices" of your 3 -D "Data Cube'M " on one screen, for fast, real time comparisons. There are, besides dozens of math and editing functions, built -in

-

clock and calendar functions, too an immensely useful convenience for scheduling, flow -charting, project management, and the like.

Watch Report Manager run -easy as A, B, C and powerful as X, Y, Z -on the PC -8000 at any NEC Home Electronics (USA) dealer.

Productivity at your fingertips

NEC

NEC Home Electronics (USA)

Sample printout showing use of X, Y, and 2 axes. Inc. Report Manager and Data Cube are trademarks of The Image Producers, CIRCLE NO. 42 ON FREE INFORMATION CARD

Personal Computer Division 1401 Estes Avenue Elk Grove Village, IL 60107

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