Electronics Worlá JULY, 1971 60 CENTS TELEPHONE ATTACHMENTS -What Is Available? MEASURING COLOR -TV GENERATED X -RAYS BE COOL-COOK WITH A MICROWAVE OVEN LIGHT EMITTERS & DETECTORS -The Optoelectronics Revolution TRANSISTOR TESTERS I ^i' it, :l : 7 'l TLJ c77 'oN 'HAS 3,\S AI I1tu 0,,10-07Pr? S; "!-ZOC9A 1.0'1 61XXE T C "' d TO OtzZZ ?kdH iCN?' How new Memorex Recording Tape shattered glass and why it will make your favorite music sound better. To shatter glass with the human voice, a singer must reach and hold the pitch it takes to make a given glass vibrate. That pitch must then be projected with enough volume to vibrate the glass to its shatter point. We figured if we could capture that precise pitch on our new Memorex Recording Tape and play it back at the same volume, we'd dramatically demonstrate the exactness with which our tape can reproduce music. So that's exactly what we did. Memorex has increased tape sensitivity, increased high -frequency response, and improved signal -to -noise ratio; so much, that now you can record your favorite music, then play it back the same way it sounded live. You should hear us. MEMOREX Recording Tape Reproduction so true it can shatter glass. Incidentally, our cassette tape also shatters glass. C 970, MEMOREX CORPORATIJ CIRCLE NO. 130 ON READER SERVICE PAGE W you can measure resistors accura N CIRCUIT in solid state devices F=21 with 41 -inch meter $99.51 FE20 HI -LO with hi- voltage probe and large six -inch meter $129.50 WITH THE NEW HI -LO FIELD EFFECT MULTIMETERS USES ONLY .08 VOLTS TO POWER OHMMETER TO PREVENT TRANSISTORS FROM CONDUCTING AND UPSETTING READINGS Look at these extra features to see why the Hi -Lo meter belongs on your want list- 9 DC current ranges from 100 microamps to 1 Unbelievable specifications of 15 megotlm input amp impedance on DC and 12 megohms on AC Automatic built -in battery test . never a worry Laboratory accuracy of 1.5 percent on DC and about rundown batteries, just push the switches 3 percent on AC under the meter and read. 9 DC voltage ranges from as low as .1 volts full Standard .6 amp fuse to protect the ohms and scale to 1000 volts milliamps scales if voltage or overload is ac- 3 hi- voltage ranges of 3 KV, 10 KV and 30 KV cidentally applied. No more need to retJm the meter to factory for repair . just replace the 9 DC zero center ranges from .05 volts to 500 fuse. volts . a must for delicate transistor bias Special probe with 100K isolation resistor in measurements probe to prevent AC pickup or to prevent loading 7 resistance ranges from 1000 ohms full scale to oscillator circuits. Leave in normal position for 1000 megohms most tests. Low voltage of .08 Here is why you volts prevents tran- should have both Hi Higher voltage of 1.5 sistors from conduct- and Lo battery volt- riwt vcl s causes semi - ing and misreading ages for correct in- ccrductors to con- // circuit. Resistor will duct to read prcper now read 10K as it circuit resistance frcrt -to -back ratio or should. Also prevents T i measurements in conductivity of taan- any damage to tran- solid state circuits: sistors. Meter wculd sistor. no: be complete vrth- ou- hi -ohms reading. CD F INC. 3200 Sencore Drive Sioux Falls, South Dakota 57167 July, 1971 CIRCLE NO. 122 ON READER SERVICE PAGE CL1 features greater protection range, many new options for security systems. 1 New CA1A CRIME ALERT() horn 87600, bell 60006 and rotating red light RRL1 Even 22 feet away, this new ultrasonic intrusion alarm are ideal for use with this option. can detect a burglar and take appropriate action. Like Option MANUAL RESET, after the intruder has been letting out a high -pitched scream or turning on a lamp floodlight, horn or bell. The built -in audible signal may detected the alarm remains on until manually turned be switched off and the accessory outlet used to give off and reset. warning at some remote location without alerting the A variety of remote alarms which plug into any 120 VAC intruder. outlet without additional wiring are available fo~ use Increased detection sensitivity isn't all that's new about with the CA1A. the CA1A. It's got four different operating options that give it greater flexibility and allow it to make use of New CA1DC CRIME ALERT© more accessories for a variety of security systems. This model operates on both 120 VAC and 12 to 18 VDC. Automatically switches to batteries if AC power fails. Option REMOTE RESET, lets you activate and deactivate Has remote reset automatic reset and manual reset the alarm from a remote location. Lockswitch RS1 is described above. Audible alarm may be switched off. recommended. Normally oper isolated relay contacts may be used for accessories such as DC bell 60007. Three Mallory M915 RESET, automatically stops Option AUTOMATIC alarm batteries are recommended for standby power. AC Accessory CAT after two minutes of operation. timer accessories not recommended for use with CA1DC. 100 must be used. Price for either CA1A or CA1DC $99.95. Option INSTANT RESET, lets alarm trip only when Accessories at additional cost. intruder moves. When movement stops, the alarm stops and is instantly and automatically reset, ready to signal Write for bulletin 9 -616 which describes the Mallory the next movement. Accessories like the weatherproof full line of security systems. MALLORY DISTRIBUTOR PRODUCTS COMPANY a division of P. R. MALLORY 8c CO. INC. Box 1558. Indianapolis. Indiana 46206; Telephone: 317- 636 -53513 Batteries Capacitors Controls CRIME ALERTm DURATAPE' Resistors Semiconductors Switches Timers Vibrators 2 CIRCLE NO. 131 ON READER SERVICE PAGE ELECTRONICS WORLD r Electronics World JULY 1971 VOL. 86, NO. 1 Contents 277 Attachments to Your Telephone Walter H. Buchsbaum hOIIICS 1rld11 What are some of the devices that can be easily attached to the phone or to the phone lines? Here are phone- company specs and requirements. along with prices. 30 Recent Developments in Electronics TRANSISTOR TESTERS 32 Zener Diode Voltage- Regulator Nomograms Chester W. Young 34 Designing a Phase -Shift Oscillator Jon L rui,no 36 Technicians in Britain E. A. Bromfield THIS MONTH'S COVER 37 Measuring Color -TV Generated X -Rays J. G. Ello shows a grouping of repre- Descriptions of the various types of survey instruments, their comparative charac- sentative transistor testers trrlstcs, and methods of checking color -TV receivers for excessive radiation. used for servicing. At the top left is the Eico 685. Below it is the Heath IM -36. At the top 40 Transistor Testers for Servicing Forest H. Belt right is the Hy- Tronix 900. At Contrary to early promises, transistors don't last forever. In order to check the bottom right the RCA WC- their performance you need a good transistor tester such as ones described. 506A is being used to check a A complete directory of such service -type testers and their specs is included. power transistor. For specs and prices on these and a number of other transistor 43 Transistor Testers and Curve Tracers -Directory testers, refer to our article on page 40 of this issue. Cover a Oven William Stocklin photo: Dirone -Denner 44 Be Cool: Cook with Microwave 46 The Optoelectronics Revolution Lothar Stern & Irwin Carroll Sold atate their extremely long lives and low power consumption, are starting to take the place of incandescent lamps and glow- discharge display tubes. Used as light sources, light modulators, indicators, detectors, couplers, and sensing arrays, here's what is available now and prospects for the future. 52 Advertising a Service Business John Frye Publisher LAWRENCE SPORN 61 Miniature Wide -Range V.L.F. Tuner N.H. Brown Editor WM. A. STOCKLILA 66 Remote U.H.F.-TV Signal- Seeking System PaulLeFevre Technical Editor MILTON S. SNITZER Managen t Editor 68 Understanding Complex Waveforms Lawrence S. Nickel PRISCILLA B. HOEFER Contrrhut,,, t WALTER H. BUCHSBAUM EW Lab Tested Prof. ARTHUR H. SEIDMAN KU-i Model 41 I ape Deck FOREST H. BELT Sony ST-5100 AM/Stereo-FM Tun Art Editor RICHARD MOSS Technical Illustra to r Reader Service Page J. A. GOLANEK Advertising Man g,v JOSEPH E. HALLORAN i, MONTHLY FEATURES Advertiui,,rt MARGARET DANIELLO 4 Coming Next Month 20 Letters Associate l'uhli; her STANLEY NEUFELD 13 News Highlights 60 Books Group Vice President Electronics & Photographic 70 New Products & Literature FURMAN H. HEBB Copyright 1971 by Ziff-Davis Publishing Company. All rights reserved July, 1971 3 Coming Next Month ALWAYS INSIST ON Special Feature Article PORTABLE Electronics CCtC ` odd SOUND SYSTEMS FOR PERFORMERS *CONTROLLED Putting together such a system is a challenge because performers are usually loud, halls frequently have poor acoustics, and there is plenty of noise and feedback. In QUALITY POPiebIC this first of a two -part series, Donald L. Patten of Shure Sound SYSIBms Brothers explains how to select, locate, and hook up CRYSTALS mikes and mixers to overcome these problems. for your Communications THE Computers and TV -like scanning techniques are helping publishers keep abreast of the information explosion. Da- Computer vid L. Heiserman explains how the RCA Videocomp "ON-CHANNEL" Typesetting works-photographing lines of type from the screen of a CRT at speeds of up to about 1000 words per second. CRYSTALS by Frank Krausser of Fisher Radio thinks so. He contends that Do We Need stereo reproduction through four channels can improve the CHYSTEK 4- Channel Stereo? listening experience considerably, provided certain psy- choacoustic factors are taken into consideration.