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How Calculator Your Personal Minicomputer

1. MAN1 MAN3M MAN4 MANS MAN 7 MANB DL707 TIE LINEAR 7402 Quad 2 input NOR gate 22ea LM301 Hi perfor AMP T05 or Mini Dip 25 ea 7403 Quad 2 input NAND gate op col 22 ea LM302 Voltage Follower 105 75 ea 7405 Hex inverter open collector 22 ea LM304 Neg Volt Regulator TOS 1 00 ea 7408 Quad 2 input positive AND gate 25ea 1M307 OpAMP super 741 Mini Dip 40 ea 7437 Quad 2 input NAND buffer 35ea M324 Quad Op AMP DIP 1 95 ea 7442 BCD to decimal decoder 95 ea LM339 Quad Comparaor DIP 2 00 ea 7446 BCD to 7 segment dec driv 30V 1 00 ea LM550 Precision Voit Reg DIP 75 ea 7447 BCD to 7 segment dec driv 15V 1 00 ea LM741 Comp Op AMP Mini Dip 3 35 ea 7472 J K Master Slave flip flop 30 ea MEMORIES aig POTENT wages 1101 256 bit RAM MOS 2 00 ea 7476 Dual J K flip flop w preset amp clear 45 ea 7489 bit read wre memory RAND TIL 2 95 ea 7490 Decade Counter 80 ea 5260 102 bit fully decod dynamic RAM 6 95 ea 7495 4bit right shift left shift register 80 ea 74121 One Shot 39 ea DISPLAYS 74164 Serial in Paral out 8 bit shift reg 2 00 ea 74193 Binary up down counter 40 P aie 300 Pos V Reg super 723 TO 5 95 ea SEA Ea l E a kat Mias Mii U ss 5 301 Hi pertormance AMP MINI DIP TO 5 45 ea SATSE PEI ESAR EMP aiea 302 Voltage Follower TO 5 95 ea Data only Refundable with
2. LED MITY DIGIT DCM S Only oe oa With spec sheets Pin for pin MAN 1 IT S NEW THE 9 DIGIT ANTEX CALCULATOR ony 9 95 7 SEGMENT READOUT Your choice of 5 red LED readouts Devices Digital Counting Modules other DCM on the market today More Serentifie form any tures than ever before Not gaseous manufacturers as Monsanto s MAN 1 MAN 4 9 99 TOT and 704 Opcoa s SLA 1 the last 1 having charac m ter heighis of 0 33 at no extra charge Each kit in eiet eludes 3x2 pe board with fingers for a FREE edge Monsanto Connector side mounting dip socket LED readout of Mansante ONT choice resistors 3 IC s and Molex connectors Citeonies this ELIMINATES SOLDERING YOUR IC s and Litronics booklet INCLUDES P C EDGE CONNECTOR FREE a Pin for pin M AN 4 elec First time advertised display on a 94 x 23 x 1 32 cerumic substrate 19 edge type connectors from substrate with connecting holes makes this unit the most useful KIND OF ELECTRONIC EQUIPMENT plexed Works with 6 95 Useful for 100 s of miniature equipment our Style C OXXXX O XXXXO O XXOXX Your Choice Any Type Type 5082 7465 5082 7466 5082 7455 4 95 4 PERFECT 4 MIDGET DIGITS ON A DIP Type of LED readouts PRICES you will advertised at 310 advertised at 8 00 low price of 4 95 for 4 digits For caleulators dyvms digital thermometers digital clocks ete
3. f z i if i h ind i pm a t f i fa ay irk A ji om A a See ree ey a g TORMOdY Week b sisted A eee o 4 w i i kr i Ar Ae e W r ee i ET EA ae ey ae pe i p Mima wD H i a i fs gA i on i a ip 7 7 he J ee re ee Pree eis F a i D t Fii me o m p rp agan r F gt py PaA EFL J A j te J 1 th Ta preter F r i k Pe LEA EY Epey z 2 l AR ARAM A a fa J oy ECEE p a en E Satie a ee hb day Gad el aa Wl eee na mi a aiy gik hs h power interconrections and storage restrictions If we were to display all the digits all the time we d need at least 80 leads for a 7 segment t0 place display This is clearly inefficient Instead we only display one digit at a time but we sequentially change which digit we display fast enough that the eye averages everything out into a continuous process Each digit is lit to many times normal brightness for a fraction of the total time The final result is a digit that is apparently continuously lit to normal bright ness This circuit trick is called display multiplexing Multiplexing is shown in Fig 2 Most calculator systems inter nally use a 4 bit BCD Binary Coded Decimal code To drive the popular 7 segment displays the chip internally converts the 4 BCD bits into the proper 7 segment patterns The output of the 7 segment converter goes to all the digits being displayed in parallel Now the trick is that we
4. H ti anaes Nie ike driver transistors ToO Taa mA i i i xy rectitiers axial leads EEE aa ENDS oe Wate eee power transistors silicon Factory Marked Order by type number Sper sheets on request ONLY Ruy 100 Take 20 la 4 BO WATT 2N1488 silicon TO3 60 Veco npn gt 85 watts 1 Type Sale D SN7432 55 Cj SN7471 SS SN74108 95 5N74160 1 95 jz Sec platio irani UNO deen T Amp 1 J SN7400 0 30 57437 ss O Envare 50 5N74112 95 SN74161 1 75 A a INS se TORR a ee an ees 1 D SN7AOL 30 D suraia al Nas 55 D SN74113 95 SN74163 1 95 Oi 6109 HOBBY 10 watts plastic powers Rane s a ages Dense 34 eN daD A cakes 5810 SN74i1a oe Biesnyaieieoce EoLA Tio 35W powers npn silicon Taney ERT eee 1 O SN7403 30 U 5N7441 1 40 O 5N7475 1 909 O SN74121 60 C SN74165 2 10 3 PLASTIC 35W powers pnp NT SB TO 18 RCA 1 O SN7493 359 DO 57442 i50 Na 65 SN74122 95 SN7 4166 2 05 2 MOS FETS N channe R chan 3N187 TD 18 RCA 1 O SN7405 35 gt aaa 1 50 SN7478 a AA E E C a e 320 2 MOS FETS DUAL GATE N chan 3N1410 TOLS RCA 4 LI N7406 aS SN7444 1180 5 Neder ase SN74126 71 5 eNeaize 2 10 2 MOS FETS DUAL GAT tors tv fm TO 18 1000me 1 N7407_ ss T SN7445 1 50 O N748 or i O SN741 x 4 RCA 2N3600 NPN UHF transisto mee ae 1 WU SN7408 35 1 SN7446 1 65 SN7482 99 Lj N74140 1 25 7 5N74177 210 2 MPF 1000 Motorola MONS dus gute i Fl SN
5. NOW you 100 E T te SPRINGFIELD MASS 01103 TEL 413 734 2737 95 RESTA g amp 815 LAKE ST TEL 612 824 2333 MISSOURI 8456 PAGE BLVD ST LOUIS MO 63130 TEL 314 428 1299 993 SYCAMORE ST i Come and see us PTS Branches are all company owned No Franchises we care for ie A our customers For a TUNER PART or COMPLETE TUNER REBUILT come to us we 158 MARKET ST 18 years experience made us what we are E PATERSON N J 07407 NORTH CAROLINA 724 SIEGLE AVE TEL 7 4 332 8007 OHIO to try P T S We are the fastest growing oldest and now the CLEVELAND OHIO 44134 largest tuner service company in the world Here is what Color Black amp White Transistor TEL 216 845 4480 you get e Tubes Varactor Detent UHF 3007 N MAY i out the same day Overnight OKLAHOMA CITY OKLA 73106 1 Fastest Service 8 hour in and ou y g 2 Fine Quality Your customers are satisfied and you are not SP GANDY BLVD bothered with returning tuners for rework UV Comb 1 6 95 TEL 503 282 9636 4 Friendly helpful service We help you do more business that Major parts and shipping PENNSYLVANIA EAST way we will do more too We want your Business and we try charged at cost PHILADELPHIA PA 19142 to deserve t Dealer net TEL 215 724 0999 257 RIVERVIEW AVE W PITTSBURGH PA 15202 overhauls more tuners than all other tuner services combined 191 CHESTNUT S MINNEAPOLIS MINN 55408 AN m f
6. i Name Address City _ State Zip Prices amp specifications subject to change without notice Mail order prices F O B factory CL 517 OESS peers vein ery es eee J EQUIPMENT REPORT continued from page 23 suppressors In following the illustrations count the traces trom the top No 1 at the left side The illustrations were prepared using standard production models of outstand ing Dolby and ANRS equipments In Fig 3 the No top trace is 30 dB ANRS in and out Trace No 2 is 40 dB in and out Note that the overall record play frequency response is within 3 dB from about 20 to 12kHz Trace No 3 is 30dB ANRS in and Dolby out Trace No 4 is 40 dB ANRS in and Dolby out Note that at 30 dB ANRS in Dolby out there is a S dB dip slightly higher than 6 kHz which flattens out as the input level is reduced to 40 dB below 0 VU or reference level In Fig 4 the No I top trace is 30 dB Dolby in and out Trace No 2 is 40 dB Dolby in and out Note that the overall record play frequency response is within 3 dB trom 20 to 12 kHz it s a different re corder Trace No 3 is 30 dB Dolby in and ANRS out Trace No 4 is 40 dB Dolby in and ANRS out Note that there is now a 5 dB peak at 3 5 kHz ut the 30 dB record level which flattens out as the record level is reduced to 40 dB While a treble boost from the amplifier could c
7. ASSORTEO RAADIO KNOBS 1l 1 standard types 2 value 50 TV KNOBS POPULAR TYPES Mostly Selector amp Fine Tuning 20 VERTICAL LINEARITY KNOBS Long shank Front mount as sortment 20 VERTICAL LINEARITY KNOBS Side mount Standard sizes 25 KNURLED SHAFT KNOBS Hard to 1 get Best selection 25 CLOCK amp RADIO KNOBS mint yop l t aai Aly 6 KITS FOR 85 TRANSISTOR RADIO asst type good 1 50 bad hroken as 19 potluck TAPE AECORDER assarted types good A bad broken as 18 potluck 7 WAY SPEAKER SELECTOR 69 SWITCH 3 Speaker 9 Wal Mount 1 75 ASST a WATT RESISTORS 1 stand choice ohmaves some in 1 UU 000 100 ASST 2 WATT peo lSmats choice vbhmages some in 5 stand 70 ASST 1 WATT o stand 1 choice ohmages some in 54 35 ASST 2 WATT RESISTORS tand 1 1 1 1 1 1 choice ohmages some tn 5 50 PRECISION RESISTORS asst pr ce 850 lesa IRE 20 ASSORTED WIREWOUNO RESIS TORS 5 10 2 watt 10 ASSORTED SLIDE SWITCHES SPST SEDT DPDT ete 25 SYLVANIA HEAT SINKS For Tranai tors 20 ASSORTED TV COILS IF sound radio ete 1 ELECTROLYTIC CONDENSERS 1 aw 00 1007100 MFD 25 V 1 ELECTROLYTIC CONDENSERS lxi 1 MFD 400V 3 ELECTROLYTIC CONDENSERS 2 238 MFD 450 V 5 9 VOLT MOTORS Excellent for hobby 8 pat list VIDEO 6 PHILIPS INVERTEO CONE 2 29 SPEAKER Top quality T
8. contained in handy roll up kit that keep tools together and in order Blades measuring 101 60 mm 4 are protected by a black oxide finish Handle dimensions are x 2 in for the smal ler drivers and 1 16 x 3 4 in for the larger Overall screwdriver lengths are 6 x 7 Ye in respectively Xcelite Incorporated Orchard Park N Y 14127 R E Circle 42 on reader service card new lit All booklets catalogs charts data sheets and other litera ture listed here with a Reader Service number are free Use the Reader Service Card inside the back cover EXECUTIVE S GUIDE TO CLOSED CIRCUIT TELEVISION 16 page brochure includes de scriptions of parts of a CCTV system camera monitor camera lens components accessory equipment videotape recorder camera hous ings Camera mounts switchers and amplifiers types of CCTV systems equipment needed and actual installations Chapter on use of CCTV equipment in producing videotapes for training and educational programs as well as glossary of CCTV terms and definitions GBC Closed Circuit TV Corp Publications Dept 74 Fifth Avenue New York N Y 10011 Circle 42 on reader service card PANEL METER CATALOG 6 page catalog de scribes line of miniature and sub miniature panel meters About two dozen different styles are illustrated that range tn size from less than 1 IN to 4 75 in wide Includes varied shapes and styles such as edge reading flat round sq
9. AUTOTEXT TEACHES YOU ELECTRONICS RAPIDLY EASILY AUTOTEXT offered exclusively by Sylvania is the proven step by step method of home training that canhelp you learn the basics of electronics quickly and easily 3 CASSETTE SYSTEM This innovative learning by hearing approach is a special option that adds an extra dimensionto AUTOTEXT It s almost like having an instructor in your own home As you play the cassette tapes you ll have an instruc tor guiding you through your AUTOTEXT lessons Explaining the material as you read it Going over schematics with you reinforcing the basic electricity and electronics study materials with you Everything you need to know to get you started towards a highly regarded position as an electronics technician all in an easy to understand Conversational tone SPECIALIZED ADVANCED TRAINING For those already working in elec tronics or with previous training Sylvania offers advanced courses You can starton a higher level without wasting time on work you already know PERSONAL SUPERVISION THROUGHOUT All during your program of home study your exams are reviewed and your questions are answered by Sylvania instructors who become per sonally involved in your efforts and help you over any rough spots that may develop G HANDS ON TRAINING To give practical application to your studies a variety of valuable kits are included in many programs In Sylvania s Master TV R
10. eotape recorders beginning in 1951 were essentially speeded up audio recorders using fixed heads and high tape speeds With develop ment of quadrature four head recorders for broadcast use and helical scan machines for industrial and educational use the simple longitudinal scan technique was forgotten but not quite Thanks to new tape frans port and signal proc ssing developments fixed head longitudinal scan recorders now are being groomed for the home VTR sweepstakes Their appeal ts relative simp licity and low price since they eliminate complicated and costly revolving headwheels and associated components Longitudinal recorders are being developed by several West Coast firms with the first demonstrations planned for this summer A typical such unit has a tape speed of 180 ips with 28 tracks on a quarter inch tape The tape whizzes past the head changes direction and the head is automatically indexed to the next track One of the problems of longitudinal VTR s in the past has been the picture blackout during the period the tape is reversing di rection Fast turnaround and storage techniques are now Said to eliminate this blackout completely Whether the new sophisti cated electronics and mechanics introduced to overcome the shortcomings of longitudinal scan will push EE E ee ee prices up to the helical scan level hasn t yet been deter mined But you can expect to hear more about this new
11. to 125 000125 special 450 MHz crystals available Self contained in small portable case Complete solid state circuitry Rechargeable batteries aa l a a dealer responsible for the changes Using a substitute tuner with any wiring brought out of the receiver to connect the tuner certainly constitutes a major change and in many cases could be a serious hazard For this reason all Subbers have car ried a warning label discouraging such consumer use Possibly there are many service techni cians who are unaware of the risks and legal responsibilities which they could face as a result of such practice and a warning against this practice is probably appropriate and timely Particularly timely in face of today s consumerism and the increasing public awareness of product hazards CEDRIC WESTERN Castle TV Tuner Service Inc Chicago Ill TV TYPEWRITER QUESTIONS In this letter you will find the answer to your question Please excuse us for the need to answer you with a form letter but it is the only practical way to handle the current volume of mail 1 Where do I get Signetics IC s Answer from Signetics long back order 2 Please send modem plans Answer not yet available Probable IC s used will be 2536 UART from Signetics and Exar 2240 and Exar 210 3 How do mount the connector pins Answer you remove the plastic block and suitably shorten the pins The p
12. 1 50 555 2 us 2 HR TIMER 1 20 7445 1 15 74193 1 45 3822 TRANSISTOR ARRAY 95 7446 1 25 74195 1 00 LM 380 2W AUDIO AMP 1 75 7448 1 30 74451 1 00 LM 377 2W STERO AUDIO AMP 3 25 7450 24 74452 1 00 LM 381 STEREO PREAMP 1 75 7451 30 75491 1 10 LM 382 DUAL AUOIO PREAMP 1 95 7472 40 8210 1 50 LM311 H PER COMPARATOR 1 15 48 8211 1 50 LM 319 DUAL HI SPEED COMP 1 50 48 8220 1 50 LM339 QUAD COMPARATOR 1 95 80 8520 Te i Similar to 8038C IC Voltage c TRIACS SCR S trolled oscillator as e ai if 1 PRY 1A 10A 25A 1 5A GA 35A Oct 73 P E they have sine square roo 80 70 7 30 AT and triangular outputs good to 200 7011 101 1 75 60 aH 42 IMHz Two of them can be used tof400 J 1 10 J 1 60 2 6011 00 20 2 20 make an FM generator 5 95 f609 1 70 2 30 3 00 __ 13 00 INEA TABL AEAN n et Ae 14 1 00 Terms FOB Cambridge Mass Send check or Money Order Include Postage Minimum Order 3 00 Send 20c at our Spring catalog featuring Transistors and Rectifiers 325 Elm St Cambridge Mass SOLID STATE SALES ast const Sewanoveron P 0 BOX 74A ___ SURPLUS HOUSE _ SOMERVILLE MASS 02143 TEL 617 547 4005 MANUALS for Govt surplus radios test sets scopes List 50c coin BOOKS 7218 Roanne Drive Washington D C 20021 Yea WATT resistors all values 2 cents minimum 2 00 LECTRONIX Box 1067 Southgate Mich 4
13. 3021 WEP 5321 WEP 56 WEP 55 WEP 55 WEP 50 NA WEP 232 WEP 232 WEP 232 WEP 232 WEP 232 WEP 232 WEP 232 WEP 232 WEP 3002 WEP 3023 WEP 701 WEP 701 WEP 3002 WEP 3002 WEP 701 WEP 701 WEP 3002 WEP 3023 WEP 701 WEP 701 NA WEP 56 WEP 716 WEP 57 WEP 57 WEP 736 WEP 736 WEP 736 WEP 714 WEP 52 WEP 50 WEP 736 WEP 56 ZEN NA ZEN 109 ZEN 109 ZEN 103 ZEN 103 ZEN 120 ZEN 120 ZEN 120 NA ZEN 105 ZEN 105 NA ZEN 208 NA NA ZEN 120 ZEN 301 ZEN 208 ZEN 208 ZEN 208 ZEN 208 ZEN 208 ZEN 208 ZEN 208 ZEN 208 ZEN 104 ZEN 103 ZEN 103 ZEN 100 NA ZEN 325 326 ZEN 326 ZEN 325 326 ZEN 326 ZEN 326 NA ZEN 326 NA NA NA NA NA NA NA NA NA NA NA NA NA NA ZEN 104 ZEN 107 NA NA ZEN 120 ZEN 120 ZEN 120 ZEN 107 NA ZEN 100 ZEN 120 ZEN 104 continued on page 68 63 Why a Syivania home training program may be your best investir forarewarding career inelectronics ent LEADER IN ELECTRONICS TRAINING Over the years Sylvania Resident Schools have trained thousands of men and women for key positions in the electronics field Now through Sylvania Home Training you can receive the same high quality career training at home In your spare time While you hold your present job Remember this training is designed with One purpose in mind to give you the background you need to land the electronics job you really want
14. 5 1 19 556 5 Times faster 1 00 A EPALE 3 FOR 36 90 j m LM 308 Hi Q fet type op lage So 1 19 558 Dual 741 DIP DIP 2 95 Pie aed tta continuous 1O watts peak With ey LM 309H 5V be helo dopey NM TO 3 1 85 560 Phase lock loops RIR 2 95 hasi Gian dich mini size Sgxlaxbu t to SiN sup _ LM 309K 5V Md i so Tale Sa 4 25 O 561 Ebaee lack E DIE 2 95 ea Riy 6 ohms Fo rE P Se LM aii H Beri Volt Comp A 1 50 5 Ses Phase jik loops A 298 Mixr s Type Watts Sale gt LM 319 Hi speed Dual Comp DIP 0 3 1 50 m 566 Function generator TO 5 393 eee oe ESE o 320 MINUS 5 12 or 24V V R T i 567 Tone decoder A 49 SANKEN HYBRID O 1 102SE 25 19 88 C e Quad Comparator DI T 2 30 A 702C Hicgrain DC amp 10 5 ao AUDIO POWER AMPS 0 S1 1050 590 mac ao Quad 4 741 s in DIP Ai 704 TV sound IF svstem 33 tensively in hi fi systems tape decks FM tru LO LM 350 Dual peripheral driver 1 19 Q 711C Dual diff comp A 169 ee ae Selita e often cel oo LM 370 AGC Sauelch op amp TO 5 3 50 723C Voltage regulator A DIP 44 ers dale A T ae amplifiers flat within dh iy LJ LM 373 AM FM SSB I A D TO 5 T Sica 741CV Freq como 709 Mini d Ments TE n Each unit properly heat sinked will C LM 374 AM FM SS IVAD TO 5 i 3 00 G 748C Frea adj 741C 41A J ea ane connecting tie lug connections Ningi z Dual 2 watt audio amp _ 3 Gain Block 98 heavy duty connecting required 24V Q LM 377 Dua 0 5 1 69 j 753
15. A typical memory from a memory stack is in Fig 6 The length of the shift register used is determined by the number of digits to be displayed plus a sign digit plus some possible locations for overflow and underflow digits Regardless of its length at any instant all four bits of a digit 40 appear at the output of a stack memory The memory ts shifted or advanced one stage at a time usually by an internally derived clock one fourth the frequency of the system clock you provide to run the IC It takes nine or more internal clockings to exactly once turn over the memory depending on the number of stages in the shift register The turn over time is called the machine cycle time and a calculator with a 25 kHz or so system clock would end up with a machine cycle time around 2 milliseconds or So If we connect a stack memory to a BCD to 7 segment decoder and then connect this decoder to our display the number stored in that portion of the memory stack will be displayed One stack memory can only store one number It takes more memory than that to do the job We need an answer memory and a keyboard memory at the very least for simple addition and subtrac tion If we are also to multiply and divide we also need an arithmetic or operand memory and as an option if we are to store a constant we would need a fourth constant memory So there are three or four separate shift register memories in our memory stack one for keyboard one for a
16. CAN HAVE D 2 TOMORROW S Y IGNITION ON eT n re te de ne Fane Ca wen or ium ree SE a 3 Bikes Controls Relan w color set Silence is YOUR CAR TODAY Eanes towomers MY golden So is H esie on back label for ten Quietrole Proven by over 100 000 in operation BN ie es Also available vi bottles and the for over five years new Silicone Don t accept as good as there are ee Silitron none neha nee i a Product of Write Today for Literature 2 UIETROLE TU D S ON Q RESEARCH AND MFG CO th E COMPANY e i Spartanburg South Carolina CONSHOHOCKEN PA 19426 a ircle 65 on reader service card Circle 30 on reader service card NEW Build and test circuits as fast as you can think No soldering or patch cords Four new Continental Specialties Proto Boards let you make all circuit and power interconnections with common 22 AWG solid hook up wire while power distribu tion buses make wiring a snap Aluminum base plates offer solid work surfaces and perfect ground plane Rubber feet prevent scratching Each Proto Board features one or more 5 way binding 4 posts to tie into system or power supply gnd All are compatible with ICs digital or linear in TO5s DIP uss packs and discrete components a Each is completely assembled ready to use ae PAT PENDING uo y FREE Proto Board 14 Pin DIP Size Price M an Model No Capacity L xW U S o
17. MIDWEST Texas Arkansas Okla Ralph J Bergen The Ralph Bergen Co 6319 N Central Ave Chicago lil 60646 312 792 3646 PACIFIC COAST Mountain States Jay Eisenberg J E Publishers Representative Co 8732 Sunset Bivd 4th Floor Los Angeles Calif 90069 213 659 3810 420 Market St San Francisco Calif 94111 415 981 4527 SOUTHEAST E Lucian Neff Associates 25 Castle Harbor Isle Fort Lauderdale Florida 33308 305 566 5656 of repair work for the last three months or who have been engaged in this work for at least one year during the three years immediately prior to January 1 1975 The license will be good for six months at the end of which period the technician must pass an exam New ap plicants must show evidence of success ful completion of a course in an approved television appliance or home entertain ment repair school Licensees must be 17 years Of age or older Proposed fees are 25 for a technician s license 50 for a shop license renewable annually for the same fee In addition there is an initial 10 fee for the application and examination Provision is made for an Advisory Committee of 14 Six of the members would have had actual experience in the Practice of servicing or repairing the equipment enumerated in the bil for not less than the past ten years Three mem bers could be from the management of electronic repair facilities three from the management
18. NA WEP 3021 NA WEP 3021 NA WEP 716 NA WEP 716 NA WEP 729 NA WEP 729 ECG 127 WEP 235 ECG 127 WEP 235 EGG 127 WEP 5005 NA NA NA NA NA NA ZEN 101 NA NA NA NA NA NA ZEN 114 ZEN 105 ZEN 104 ZEN 105 NA ZEN 114 ZEN 115 ZEN 115 ZEN 118 ZEN 115 ZEN 115 ZEN 175 NA NA NA NA NA NA ZEN 107 NA ZEN 119 ZEN 103 ZEN 103 ZEN 111 NA ZEN 103 ZEN 103 ZEN 103 ZEN 107 ZEN 107 ZEN 115 ZEN 115 NA ZEN 328 NA Indicates a dual transistor for high speed switching diff amplifier etc Likely to be a matched pair Use two of the type specified matching when necessary On a curve tracer or lab type transistor checker NA NOT AVAILABLE 68 tie Fan continued next month Blanking circuits why and how they work Symptoms are often weird but easy to blank out Here s how by JACK DARR SERVICE EDITOR This column is for your service problems TVY radio audio or general and industrial electronics We answer all questions individually by mail free of charge and the more interesting ones will be printed here If you re really stuck write us We ll do our best to help you Don t forget to en close a stamped self addressed envelope If return postage is not included we can not process your question Write Service Editor Radio Electronics 200 Park Ave South New York 10003 R E s Service C WHAT IS BLANKING THE CLINIC MAN BAG gets pretty heavy sometimes wi
19. and Sperry neon displays have a well defined threshold that also eliminates the problem Liquid crystal readouts do not inherently multiplex very well and for this reason very few calculators use the otherwise ideal liquid crystal display systems m Driving a display Ideally we d like to come directly out of our calculator IC and go directly to the display without needing any interface circuitry at all Sl etal Aad ry a Pitti tala Pai DISPLAY AND DRIVERS CALCULATOR IC eR KEYBOARD FIG 1 CALCULATOR BLOCK DIAGRAM Keyboard generates 4 bit BCD numerals The clock a multivibrator controls operational se quence DIGIT LINES LIGHTS EXTINGUISHES ONLY ONE DIGIT DRIVER LINE GOES THESE LINES Bizio 51 41 3 ol 4 DECIDE WHERE ete AT ANY NUMERAL IS TO BE DISPLAYED Y V V V VNV V VW WV ALL SEGMENTS WIRED IN PARALLEL TO RESPECTIVE ON OTHER DIGITS THESE LINES Sey DECIDE WHAT NUMERALIS TO BE DISPLAYED a b c d e fig SEGMENT LINES LIGHTS EXTINGUISHES FIG 2 THE SEVEN SEGMENT READOUTS ARE MULTIPLEXED to re duce circuit interconnections and instantaneous power drain Unfortunately every display system in use today has some interface restrictions Owing to needing more current or more voltage than a calculator IC can provide Some typical interface circuits are shown in Fig 3 In the case of neon type displays Fig 3 a drive voltage is usually the problem Mo
20. can be checked with an ohmmeter VDR s must be substituted they can be checked but it is a long process Besides no one ever gives you any spec s on VDR just the part number R E REPLACE HV OK HV REG ORIG TUBE TUBE BAD R E s Substitution guide for replacement transistors PART XVII compiled by ROBERT amp ELIZABETH SCOTT ARCH indicates the Archer brand of semiconductors sold only by Radio Shack and Allied Radio stores Allied Radio Shack 2725 W 7th St Ft Worth Texas 76107 DM D M Semiconductor Co P O Box 131 Melrose Mass 02176 G E General Electric Co Tube Product Div Owensboro Ky 42301 1CC International Components 10 Daniel Street Farmingdale N Y 11735 IR International Rectifier Semiconductor Div 233 Kansas St El Segundo Calif 90245 MAL Mallory Distributor Products Co 101 S Parker Indianapolis Ind 46201 MOT Motorola Semiconductors Box 2963 Phoenix Ariz 85036 RCA RCA Electronic Components Harri son N J 07029 SPR Sprague Products Co 65 Marshall St North Adams Mass 01247 SYL Syivania Electric Corp 100 1st Ave Waltham Mass 02154 WOR Workman Electronic Products Inc Box 3828 Sarasota Fla 33578 ZEN Zenith Sales Co 5600 W Jarvis Ave Chicago Ill 60648 Radio Electronics has done tts utmost to tn sure that the listings in this directory are as ac curate and reliable as possible however no re sponsibility is assumed by
21. detector is first fed to a de differential amplifier consisting of Q102 Q103 and FIG 3 CONNECTION POINT FOR CONVENTIONAL center of channel FM tuning meter FIG 4 TYPICAL RATIO DETECTOR S curve swings over wide positive and negative dc voltage range For proper tuning 0 dc point must be exactly 10 7 MHz as shown Q104 In addition to affording accurate de offset control by means of VRIOT stable temperature tracking and isola tion from the circuits which follow this arrangement also provides the oppor tunity for frequency compensation so that the effective output of the FM de modulator has flat response all the way from de to 100 kHz important for the multiplex decoding circuitry to follow later This composite signal is fed via C20 to gain control VR201 and on to a T section filter consisting of C204 L201 C203 and C205 This high pass filter has a voltage gain of several dB at noise frequencies of about 110 kHz while effectively rejecting all lower fre quencies of the composite stereo audio signal The random noise frequencies are passed on to a high gain feedback pair of transistors Q201 and Q202 With no rf signal received condition of maximum random noise the peak to peak voltage at the output of Q202 is quite high approaching 30 volts R208 and Q203 form a voltage variable at tenuator in what amounts to an age loop while Q204 and Q205 are another high gain pair of transistors wi
22. g lase rectifiers signal axial leads 31 C amp M 13 MU RICIEI REEL R 9 R m sev aaa 3 50 GERMANIUM gla bmini silicon rectifiers C LM 1307 FP E RF IF amp 1 50 O 301 1 O 592 5 for 1 AMP 1000 PIV epoxy su fi 1 E 3028 Differential r 95 O 307 10 tor 1 1 Ow a OMW ZENERS acnal 4 6 9 10 12V recti 0 3 Sie Hi cm sooo Geet current mirror amp 9S 308 5 for 1 O 703 Sl D 4 2N3055 HOBBY 10W Ea ay Heeger e e A Sie A im e250 programabie oP amp ae z Zook Glovers Oos dororti 4 3 T CTIFIERS silicon epoxy assorted a a vpe 1 l 1 Dual peripheral driver 80 3 tor 1 0O 710 1 earner CT 1000 Y dumb tvp T a UE 5 al driver 44 H3 1 O 711 10 for 1 2 EPOXY 2 AMP SILICON BRIDGE RECT B es rs ogee nines LED DIP 1 65 O 381 pa 1 723 5 for 1 j filter 7549 uad se e 85 516 or 1 O 1 PHOTO TRANSISTOR With aran AR A QNSTT7 EM daS Hex digit driver 250ma DIP 1 8 4 mee ey a 733 Pr a F 4 PHOTO CELLS Giniren pancake S0K 70 ohms AY TO 5 Dip gt O sss 4for 1 07 0 a 2S 2 1 oz gt VER 1 000 000 PC INVENTORY s 15A TO 3 transistor 1 a Buy 3 1 2N3055 npn 100W a Fi T Buy 3 S 5 ER900 TRIGGER ote SSON anion TO 92 plastic a se a i SEA cube Ht to Savant cc E silicon 4 nanoseconds 1 discount ia 10 aE 0 5 oe et ee en ee Ne ee dom Edo EP ERG Aiki REEYir IERS aiicon yoreeluin to IkV E O 40 CT amp zeners W assor v LEST RE z 1
23. important information The cost of this 52 page package is 5 00 plus postage Use the coupon below to order Fill out the portion with your name and address You must print as it will be used as your shipping label Then check off the way you want it shipped this determines the price Mail your check or money order with the coupon to Radio Electronics Micro Computer P O Box 1307 Radio City Station New York N Y 10019 Pay ment must be in U S currency Radio Electronics Micro Computer P O Box 1307 Radio City Station New York N Y 10019 MUST PRINT Name Address City State Zip Brochure price 5 00 postage is addi tional U S Canada First class mail 5 50 U S Canada Air mail 5 65 Foreign Surface 5 90 Foreign Air mail 7 30 Only these four methods of shipment can be provided New York State residents must include 7 sales tax Brochures will be mailed within three weeks of receipt of your order 30 The heart of the Mark 8 Minicomputer is an Intel 8008 microprocessor C that con tains all of the arithmetic registers sub routine registers and most of the control logic necessary to interface the micro processor with semiconductor memories as well as input and output registers Standard TTI type IC s are used throughout and commonly available PIOI IOLA and LIOLAL type memories are used lor the cen tral Storage The microprocessor with its as
24. zontal output tuhe the high voltage reg ulator may have incorrect hias on tt This will cause an overload It can happen tn all types of high voltage regulators if the dc voltages are off The old shunt regulators are the easiest to check Just pull the plate cap off the reg ulator tube place it where it can t are to ground if the high voltage does come back Recheck If your high voltage rises to ahout 30 KV the regulator is overloading it Screen brightness and focus should be close to normal Try a new regulator tube If this still doesn t clear it up go to the de voltages on the regulator In practically all circuits using this circuit you ll find a k resistor in series with the cathode of the regulator tube This is for ease in reading the regulator cathode cur rent Just connect a vom across the k resis tor and set it on a low dc voltage scale For each 1 0 mA of current flowing you ll see a 1 0 volt deflection of the meter For practically all of these sets using 6BK4 s and similar tubes normal regulator current should never be more than about 1 0 mA with the pucture tube screen dark maximum current flowing in regulator This should drop to about 0 1 or 0 2 mA with the brightness full up If you see more than 1 5 to 2 0 mA with a bright screen the regulator is taking too much current This will overload the high voltage supply and you ll probably see an overload of cathode current in the horizontal output tu
25. 9465 1 50 ea 3 4 00 MJ2252 NPN S TO 66 90 R 2037 noon Soe 2N3638 PNP Si TO 5 5 1 00 y PRINTED CIRCUIT BOARD 2N2218A NPN Si TO 5 4 1 00 CD 4030 REEE S LEN 4v2 x6Y2 double sided fiber CAPACITORS MAN 1 RED OR YELLOW Full Wave Bridges glass board 1 16 thick un 6V 30 UF TANT 5 1 LED READOUT 3 25 T OV IOUR ELECT S a t BRV 2A GA i READDUTS 1 75 200 95 1 25 setea 8280 coy 100UF ELECT 8 40 MANGLED 1400 ts 186 NIXIE TUBES 25V 30UF ELECT 4 1 00 READDUTS 2 50 600 1 35 1 75 Similar to Raytheon 8650 1103 1024 bit RAM 6 25 5311 CLOCK CHIP 6 DIGIT BCD tubes with socket amp data Bede E PRAM e OID O TE a i yee e 5314 CLOCK CHIP 6 DIGIT HOLO sheet 2 25 3 6 00 8225 PROGRAMMABLE 2 75 COUNT OUTPUT STROBE 8 50 NSN 33 3 DIGIT LED 5316 ALARM CLOCK ARRAY MAN 3 SIZE 12 CON aa 6 25 CHIP l __ 13 95 INTERNALLY MULTIPLEXED AND TANE Elastometer low Injection laser a single diode DRIVEN BY 7448 1 95 EA profile calculator keyboard A OW 25A Ga As unit similar to RCA 40859 10 95 SANKEN AUDIO POWER AMPS S 1010 Y LOWATTS 7 95 2 x 3 flex key 19SK 6 keyboard having 0 9 e K C buttons with VERIPAX PC BOARD ele isa 1 16 nee off on switch 6 00 Si 1025 E 25 WATTS 18 88 ided paper epoxy board Si 1050 E 50 WATTS 29 95 4Yo x6YV2 standard ver 0 TTL Ie SERIES 52 TIS 7 T aE 7 ina DRILUED sn
26. ASST RADIO amp TV TUBES Ever 1 Tube a good number 5 AUDIO OUTPUT TRANSFORM Sut min for Trans Radioa 5 LF COIL TRANSFORMERS 456 kc for 8 Transistor Radios 6 UNIVERSAL SPEAKER Top qualts 1 29 Special buy Ea ALL AMERICAN TUBE KIT 12A 6 2 95 IZBE6 12BRA6 35 W 4 005 F STEREO MICROPHONE S Fl 197901 Made In Holland G se C UTAH CELESTA 3 WAY co axs 4 6 95 SPEAKERS 8 10 oz Mag 30 Watts UTAH CELESTA 3 WAY CO AX 24 95 SPEAKERS 127 20 o2 Mag 45 Watts VU 1 PANEL METER 1 29 O edhe Seale 8 MINITURE PILOT BULBS With 8 Leads 6 3V MA CARMI ICs orca aes were eee 1 E 8 MINITURE PILOT BULBS Wn 127 keid hav 150s IC 5000 dirs 1 Only applies to 1 Buys is waiting Control adjusts playback volume without affecting recording A fod onnonppooonongon oo0g00 Goo0000000000 OO aonan HOTTEST NEW VALUES FREE 1 BUY WITH EVERY 10 YOU ORDER CANADIANS Ordering is easy we do the paperwork try a small order RCA 110 SHANNON TRAN Re Illuminated 250 ASST SOLDERING LUGS test types 8 and sizes zou ASST WOOO SCREWS finest popu ar selection 250 ASST SELF TAPPING SCREWS 6 8 aM ete 100 ASST 6 32 SCREWS and 100 6 32 HEX NUTS 100 ASST 8 32 SCREWS and 100 8 32 HEX NUTS 100 ASST 2 56 SCREWS and 1002 56 HEX NUTS 1 100 ASST 4 40 SCREWS and 100 4 40 HEX NUTS 51 100 ASST 5
27. Catalog WE WANT TO BUY your used FM Gen eral Electric R C A and Motorola 2 way base stations and remote units IS YOUR BLOOD PRESSURE HIGH Only your doctor can contro hgh blood pressure Protect yoursalt 2 ways radios Get regular CALL US TODAY modical MOTOROLA D43GGV 3100 150 to 170 MHz GENERAL ELECTRIC MT42 450 470 MHz q am checkups and support yout Heart Associaton s fight against this leading Cause at t i 4 heart aftacas and Sirokas om Eh maT 12 volt 15 watts transistor power supply 6 12 volt 30 watts front mount with private line fully narrow band _ 88 ea j In 17 case multi freq deck wide band less ovens w accessories 88 nb oF HEART FUND GREGORY ELECTRONICS CORP PEF 251 At 46 Saddle Brook N J O07662 Phone 201 489 9000 this stripped down recorder will save your listening machine from a lot of wear Full track half track mono or stereo any old recorder will do as long as the forward rewind mechanism works The electronics is removed or deactivated Start by cutting the power leads to the recorders power supply testing the motor drive after each wire is removed to see if you cut an electric interlock circuit If so trace it out and rewire its circuit with a new wire H there is no power line fuse add one Remove any mechanical parts not connected with t
28. Easier Starting under any condition Increased Horsepower Sparkplugs last longer Perfect timing increases engine Efficiency and Gas Mileage up to 30 Quick and Easy Installation Tested and Proven reliability Only 4095 SATISFACTION GUARANTEED Complete 1 YEAR FACTORY WARRANTY State Make Year Engine Size Calif Res add Tax CCNVERT YOUR C D UNIT TO BREAKERLESS TRIGGER UNIT ONLY 34 95 Kk Send Postcard for FREE BROCHURE Today ALLISON AUTOMOTIVE CO P O Box 881 L TEMPLE CITY CAL 91780 Now the most enjoyable do it yourself project of your life A Schober Electronic Organ You ll never reap greater reward more fun and proud accomplishment more benefit for the whole family than by assembling your own Schober Electronic Organ You need no knowledge of electronics woodwork or music Schober s com plete kits and crystal clear instructions show you whoever you are whatever your skill or lack of it how to turn the hundreds of quality parts into one of the world s most beautiful most musi cal organs worth up to twice the cost of the kit Five superb models with kit prices from 500 to around 2 000 each an authentic musical instrument actually superior to most you see in stores easy for any musically minded adult to learn to play yet completely satisfying for the accomplished professional And there are accessories you can add any time after
29. Equipment Report JVC CD 1668 cassette deck New Hi Fi Test Gear What itis and how you can put it to work by Robert F Scott New FM Tuning Circuits Precise tuning is made easier by these interesting new circuits by Len Feldman Direct Coupled Audio Circuits Theory and design using solid state amplifiers by Mannie Horowitz TELEVISION 60 69 71 Step By Step Troubleshooting Charts Inside the high voltage regulator by Eugene Cunningham Service Clinic Blanking by Jack Darr Reader Questions R E s service editor solves reader problems DEPARTMENTS 98 92 87 16 Advertising Index Books 81 New Literature Circuits 78 New Products Letters 90 Next Month New amp Timely 101 Reader Service Card DOME S2 LAMP 12V ae L S S1 DOOR HEAD SWITCH LAMP NORMALLY SWITCH INSTRUMENT PANEL LAMP GROUND AN AUTOMOBILE HEADLIGHTS ON REMIN DER you can build as you study and become familiar with SCR s and their operation see page 42 Hugo Gernsback 1884 1967 founder M Harvey Gernsback editor in chief and publisher Larry Steckler CET editor Robert F Scott W2PWG CET technical editor Jack Darr CET service editor 1 Queen editorial associate Leonard Feldman contributing high fidelity editor David Lachenbruch contributing editor Barbara Schwartz editorial assistant Vincent P Cicenia production manager Sarah Martin production assistant Harriet Matysko circulation di
30. FOR 6 READOUTS BY THE DIGIT LOWEST PRICE ANYWHERE 1 Per Digit BUY ANY 9 DIGITS FOR s Lag Four Poly Paks pus complete National inventors of eligi missing NS5SN 343 Same as the 2 50 unit R Migi l out Properly Sioned a that you may use eg Hl units Line up as you Sh ena ret the desired comh nation Zero means that digit is missing ponera meaning 1004 good unit LOWEST PRICES A WHERE Imagine not 1 80 per digit Dut 1 00 per Char Hach Speci al gD EA 1 27 3 75 3 for 9 MAN 3 12 1 49 3for 3 MAN 4 19 2 50 3 tor 6 REFLECTIVE BAR TYPES 707 33 2 50 3 for 6 707 33 2 50 a 6 1 33 2 10 or 5 H SLa 3 x 70 4 95 3 for 13 By Litronix By Oncoa equal to F SLA 11 33t 3 50 3 tor 10 MAN 1 or MAN 4 specs Color RED O sta 21 33tt 3 95 3 for 10 Green tt yellow B National their Type NSN 33 With red lens filter Properly milifplesetk Three digits siz ee of MAN 3 Driver SNTAJIN 10 mils Case only Fi Aa BRN a 68 12 pins Por pe boards n l S itl 3 dard IC soeket For vdeulators DCMS DVM Clack and 1000 s of indieuting devices Price is lawest we have seen 100 perfect Buy all good limits ae re jeets as the Hewlett Packard s advertised by others ixit WILY PAY MORE Order by digit and save Take 10 READOUT Uhar MAN 1 27 b MAN 4 19 b 707 33 bh 0 704 33 h SLA 1 33h
31. Gordon St S W Lowers ones tae orgy TS 404 298 2232 er 737 Wy 55th SU oe aides eee eae ee ss gle Ne ome 3 5556 7 9110 W Brown Pa e ee oe Ql 12 675 0230 prers6t7 N PennsyWivania SK P 4 a Tel 632 3493 e ET 6833 Grand Av s TEN Tete 219 845 2676 2920 TattorBiva Le Dan ee G 502 634 3334 3025 Highland Avey Pe Lgl 318 861 7745 5505 Reisterstowe Rd P 2628 el 301 358 1186 P tTOst PagdAve SET af za el 314 429 0633 1 1412 Western Ave z i T o hl 702 384 4235 547 49 Fe te Ave i gt Highway amp 9 rel 201 792 3730 901 N Olden Ave TE Tel 609 393 0999 L 7480 Vine St pe ra Tel 513 821 5080 mn oe 4597 Pearl Rogd er Tel 216 741 2314 1732 N V 25thWWre alt Tel 503 222 9059 a 1215 Snapps Fefry Rd Reese Tel 615 639 8451 3158 Barron AE TT Ne ss Tel 901 458 2355 abe weg 14540 Garad Rd 0 0 0 o Tel 214 327 8413 bas mb 4538 E Princess Anne Rd Rgkj804 855 2518 9955 Franchises available Contact headquarters for information Circle 3 on reader service card 20th anniversary of color TV marks end of tube regime RCA celebrated the 20th year of color TV on March 25 1974 with an announcement that it was abandoning tubes altogether in its new 1974 line of TV receivers With the obvious exception of the kinescope the RCA XL 100 color TV line is completely solid state Pre er
32. Hz by a series of binary dividers then further divided for the minutes and the hours by counters and drivers that ac tivate light emitting diodes LED s or 6 LIGHT DIGIT SEGMENT EMITTING DIODES CRYSTAL QUARTZ TRIMMING RCA INTEGRATED PHOTO CAPACITOR CIRCUIT DOBE THE WORKS OF A DIGITAL WATCH seen with the faceplate removed The batteries are behind the circuit board The photo diode increases or decreases the disptay s bright ness according to the amount of ambient tight segments of liquid crystal numerals to display the correct time with an accu racy 10 times greater than that of mechan ical or electromechanical timepieces The integrated circuit that does the work contains more than 1300 transistors on a match head size silicon substrate Electronic revolution limiter tells motorist when to shift A new aid to the sports car enthusiast an electronic revolution limiter is now available The motorist says Siemens who introduced the device is likely to overlook the fact that his motor is speeding up to the point of possible engine damage especially when all his attention is being engaged by traffic conditions The new device reminds him to shift up when the engine reaches its preset revolution limit The limiter is a measuring amplifier with a gate function Squarewave pulses from the rev meter are rectified and filtered and the resultant dc voltage compared in an operation
33. IR IRTR 65 IRTR 70 TR 21 TR 21 IRTR 51 TR 25 IRTR 87 IRTR 87 IRTR 83 IRTR 83 NA NA NA NA NA NA NA NA IRTR 95 TR 24 TR 24 NA NA TR 01 TR 01 TR 01 TR 01 TR 01 TR 01 TR 01 TR 01 NA NA NA NA NA MAL PTC 144 PTC 115 PTC 121 PTC 139 PTC 153 PTC 123 PTC 123 PTC 123 PTC 127 PTC 127 PTC 127 NA NA NA NA PTC 103 PTC 103 PTC 103 PTC 127 PTC 144 PTC 144 PTC 144 PTC 123 PTC 107 NA NA NA NA NA NA NA NA PTC 133 PTC 136 PTC 136 PTC 136 PTC 152 PTC 105 PTC 105 PTC 105 PTC 105 PTC 105 PTC 105 PTC 105 PTC 105 NA NA NA NA NA NA PTC 136 PTC 103 PTC 127 PTC 103 PTC 123 PTC 123 PTC 136 PTC 127 PTC 127 PTC 136 PTC 136 PTC 133 MOT HEP S3001 HEP 720 HEP 720 HEP 55 HEP 55 HEP 736 HEP 736 HEP 736 NA HEP 709 HEP 709 HEP 803 HEP 803 HEP 803 HEP 52 HEP 52 HEP 52 HEP 52 HEP 52 HEP S3021 NA NA HEP 736 HEP 3 HEP S3021 HEP S3021 HEP S3021 HE P S3021 HEP S3021 HEP S3021 HEP S3021 HEP S3021 HEP 56 HEP 55 HEP 55 HEP 50 HEP 803 HEP 230 232 HEP 232 HEP 230 232 HEP 232 HEP 232 HEP 625 HE P 232 HEP 625 HEP S3002 HEP S3002 NA NA NA HEP S3002 NA NA NA HE P S3007 HEP 56 HEP 716 HEP 57 HEP 57 HE P 736 HEP 736 HEP 736 HEP 716 HEP 708 HEP 50 HEP 736 HEP 56 HEP R1301 HEP R1302 HEP R1304 HEP R1306 HEP R 1307 RCA NA SK 3018 SK 3018 SK 3124 SK 3124 SK 3024 SK 3124 SK 302
34. Ln Indpls In 46224 tion maintains solid rigidity improves signal transfer Use of lustrous gold colored alodized aluminum protects antenna All band vhf uhf FM splitter is included with each of seven models model LPV UC180 far fringe LPV UC150 fringe LPV UC120 near fringe LPV UC90 suburban fringe LPV UC60 suburban LPV UC40 local suburban LPV UC30 local JFD Electronics Corp 1462 62nd Street Brooklyn N Y 11219 Circle 40 on reader service card OSCILLOSCOPES models To 55 amp TO 66 TO 55 is a single trace instrument TO 60 is a dual trace instrument Automatic features in clude astigmatism and automatic selection of TV vertical and TV horizontal triggering Vertical sensitivity of both instruments has been in creased to 10 millivolts em TO 55 vertical bandwidth ts 10 MHz while TO 60 has a 15 MHz system All switching is done in the 1 2 5 step sequence TO 60 provides five operating modes for the dual trace vertical amplifier These include in dependent operation of each channel plus dual trace alternate and dual trace chopped and the sum of each channel Letrotech Inc 5810 North Western Avenue Chicago III 60659 Circle 4 on reader service card HEX SOCKET SCREWDRIVERS LN 8MM Set has fixed handle and comes ina range of metric sizes that are available as a set or individually Set consists of eight drivers with black plastic handles and hex tip sizes from 1 27 mm to mm
35. SK 3124 SK 3124 SK 3045 SK 305 SK 3036 SK 3036 SK 3036 SK 3025 SK 3025 SK 3124 NA SK 3104 NA NA NA NA NA NA SK 3034 SK 3035 SK 3034 SPR NA NA NA NA NA NA RT 108 RT 108 NA NA RT 131 NA NA NA RT 115 RT 115 RT 115 NA NA RT 115 NA RT 102 NA NA NA NA RT 110 NA RT 115 RT 115 RT 1 2 RT 102 RT 102 RT 102 RT 102 RT 102 RT 102 RT 102 RT 110 RT44131 RT 131 RT 131 RT 131 RT 115 RT 115 RT 108 NA NA NA ZEN NA NA NA NA NA ZEN 208 NA NA ZEN 104 ZEN 104 ee oo al SYL WOR ECG 5501 NA NA NA NA NA NA NA NA NA NA NA NA WEP 242 NA WEP 242 ECG 107 WEP 56 ECG 107 WEP 56 NA WEP 3021 NA WEP 3021 ECG 130 WEP 704 NA NA NA NA NA NA ECG 129 WEP 51 ECG 159 WEP 57 ECG 159 WEP 57 NA WEP 3002 NA WEP 3002 ECG 129 WEP 52 NA NA NA WEP 728 NA WEP 709 FCG 108 WEP 56 NA WEP 709 ECG 133 WEP 801 ECG 133 WEP 801 ECG 133 WEP 801 ECG 133 WEP 8014 ECG 108 WEP 728 ECG 108 WEP 729 ECG 108 WEP 729 ECG 108 WEP 723 ECG 108 WEP 729 ECG 108 WEP 729 ECG 123A WEP 729 NA NA NA NA NA NA NA NA ECG 154 WEP 3021 NA WEP 3021 ECG 159 WEP 716 ECG 159 WEP 57 ECG 123A WEP 735 ECG 123A WEP 55 ECG 123A WEP 55 ECG 123A WEP 723 ECG 123A WEP 732 ECG 123A WEP 55 ECG 123A WEP 55 ECG 123A WEP 55 ECG 154 WEP 3021 ECG 130 WEP 247 ECG 130 WEP 704 ECG 130 WEP 247 ECG 130 WEP 704 ECG 129 WEP 242 ECG 129 WEP 242 ECG 107 WEP 54 NA WEP 3021 NA WEP 3021
36. T s i ow TELEQUIPMENT ve a ERE A T Osc ioscope 061 off z E a Ee i i p 4 fe ae i En nee ama Cael 1 def ce o i ih Ea oe a E EE if ars m i reiii cal O Svpp probe test Chre 1 Channel 2 4 i i Tropa gh volts divisien i positon cee ine pui 5 time division 1 500 2 200 mS AO 100 pS ir ten vo4s division tog ievel pull auto DL ag i ga ext cht ch2 W de 7 PO Ea PETA oF Yee triq ext x rates up to 100 ns div It is ideally Suited for students technicians frame displays are selected automatically in the TV trigger position And chopped or alternate modes are deter mined automatically to optimize display clarity Bright stable viewing Stable waveforms displayed on an 8 x 10 cm crt are easy to view even under unfavorable ambient light conditions Two identical inout channels sim plify generation of X Y displays This is particularly useful in analysis of vector patterns Application versatility Because of its X Y Capability the D61 simplifies alignment and troubleshooting of color television sets Its performance equals or exceeds the require ments for servicing audio equipment pocket calculators public safety control alarm and communications systems microwave ovens digital clocks and similar co
37. Volts P C 5 for 1 00 150Mfd 150V 50Mfd 50 V 3 for 1 00 100 Mfd 50 Volts 4 for 1 00 5 Mfd 250 Volts 0 0 5 for 1 00 l6 Mfd 450V ro eee oe 4 tor 1 39 30 Mfd 450 Volts 3 for 1 19 10 Mid 600 VONS 2 225 255 3 for 1 00 25 Asst d Axial Leads 3 95 25 Axial PC Trans Work 3 95 COLOR CRT BOOSTER 70 4 29 COLOR CRT BOOSTER 90 4 59 70 Conv Assembly 1 79 TUNERS SYLV TRANS 54 29331 3 6 95 SYLV TRANS 54 35055 2 6 95 GEN ELECT TRANS 86X15 6 95 G I PARALLEL 6GS7 6HAS 3 95 SYLV SER 54 27887 1 5GJ7 3HA5 5 95 PHILCO SERIES 76 13579 6 4 95 G E Seriles 5GJ7 3HAS 5 95 G E Par ET38X3J 8 a eee 6 95 MINIMUM ORDER 15 00 SEND FOR FREE CATALOG TUBES UP TD 80 OFF SEND CHECK OR MONEY ORDER TV TECH SPECIALS P O BOX 603 Kings Park L I New York 11754 86 Circle 62 on reader service card EQUIPMENT REPORT continued from page 26 driven from the cassette take up spindle Attached to the counter drive is a shutter or segmented disc similar to rotary shutters used on some movie projectors Fig 5 On one side of the shutter is a small lamp on the other side is a photocell whose output LAMP CDS PHOTOCELL AC TO EJECT SOLENOID CONTROL SHUTTER BELT M SHUTTER TAKE UP REEL HOLDER Fig 5 feeds an amplifie
38. a solid state preamp lifier circuit with adjustable output of 0 30 dB gain to match most transceivers input require ments Slide switch on the underside permits selection of relay or electronic switching Press to talk bar may be locked in talk position Frequency response is 100 8000 Hz impedance is 1000 ohms cable is six foot three conductor coiled cord with plug Fanon Courier Corp 990 South Fair Oaks Avenue Pasadena Calif 91105 Circle 34 on reader service curd DIGITAL MULTIMETER mode 134 is a3 V2 digit five function full range DMM digital multime ter with bright Yz inch seven segment planar gaseous display Has 1999 count display and automatic decimal point positioning Displays three full digits plus overrange one for all functions with minus sign displayed and plus sign implied Offers direct digital reading with no analog interpolations necessary for positive Be TH bee See AGG Piece and negative dc volts and current automatic polarity ac volts ac current and resistance Dc volts 4 ranges 1 000 V to 1500 Vf s with 100 overrange in each range to a limit of 1500 V Sensitivity is 1 mV on the 1 volt range Input resistance is 10 megohms on all ranges Accu racy on all dc voltage ranges except the 1 kV range is 0 2 f s 0 2 reading The 1 kV range accuracy is 0 5 f s 0 5 reading On the ac range frequency response is 50 Hz to 1 kHz extended to 5 kHz at slightly r
39. aid will be available by the time this appears he says Write for it to the same address Grid clamps diodes and VDR s A very simple form of high voltage regu lation is used in Some sets mostly the small er screen types with lower high voltage This uses a diode rectifier in the grid return circuit of the horizontal output tube Figure 3 shows a typical circuit The diode D1 is biased by a resistor network back to B plus The pulse from the flyback wall cause the diode to conduct whenever the voltage goes above the bias level The diode conducts and charges the Capacitor This is a negative voltage It s fed to the bottom of the hori zontal output tube grid resistor If the high voltage tries to rise the pulse voltage also rises This makes the diode de velop a higher negative voltage This is fed to the grid as a higher negative voltage This cuts down conduction of the tube and the output drops back V11 6LE6 HORIZ OUTPUT The VDR clamp You ll find VDOR s Voltage Dependent Resistors used in some of these circuits These are rather special resistors When the voltage across them rises their resistance goes down So they will actually act as rectifiers if a high amplitude pulse is fed across them The resulting de voltage will have the same polarity as the applied pulse If this is a negative going pulse a negative de voltage will appear etc Figure 4 shows a schematic of this type Y
40. as d with hum in the trace SWITCH TYPE FREQUENCY SELECTION is used in Heathkit IG 18 solid state sine square wave generator for precise resetabil ity A bridged T oscillator is used Frequency range is 1 Hz to 100 kHz sinewave and 5 Hz to 100 kHz squarewaves Sine and squarewaves are available simultaneously Distortion on sinewaves less than 0 1 Square wave rise time less than 50 ns Sine wave output adjust able from 3 mV to 10 V in eight ranges square wave output 0 1 to 10 Vp p in three ranges A 212 in panel meter indicates output levelin volts and in dB 0dB 1mWinto 600 ohms An internal 600 ohm load resistor can be switched into the circuit on all output ranges up to 1 V In setting up the first two significant figures of the frequency are selected on 0 100 and 0 10 switches the third figure on a 0 1 vernier con trol Multipliers are set by X1 X10 X100 and X1000 switch PUSH BUTTON ATTENUATOR and a continu ously variable control adjust the output of the B amp aKk Precision E 310B sine squarewave generator from the maximum of 8 Vrms to less than 0 25 mV Its sinewave frequency range is 20 Hz to 2 MHz in five decade ranges Distortion is 0 1 typical 0 25 maximum Maximum am plitude variation over the frequency range is 1 dB Frequency calibrations accurate 2 100 Hz to 2 MHz 2 or 1 Hz below 100 Hz Squarewave frequency range is 20 Hz to 200 kHz in four decades Output is 0 to 10 V peak
41. connector Misc PC board No 24 wire solder LED REGISTER DISPLAY BOARD C1 100 uF electrolytic C2 C3 C4 O 1 uF disc D1 thru D32 MV 50 MV 5020 or equivalent Red visible LED s IC1 thru IC6 7404 IC7 C8 7475 quad latch IC9 7442 decoder IC 10 7402 P1i Molex type 09 52 3081 connector R1 thru R32 220 ohms Misc PC board No 24 wire Solder CONTROL PANEL D1 MV 5020 or equivalent red visible LED R1 220 ohms S1 thru S11 spdt switches rocker or toggle 513 thru 17 spdt momentary spring return rocker or toggle PS Power supply logic power supply available from Precision Systems P O Box 6 Murray Hill NJ 07974 5 volts 8 5A and 12 volts 2 0A adjustable to 9 volts Also other voltages available See text Misc Metal case red plastic filter line cord hardware hook up wire solder The microprocessor integrated circuit is available from Intel Corporation 3065 Bowers Avenue Santa Clara CA 95051 at a cost of 120 00 A complete set of circuit boards is available for the Mark 8 Minicomputer from Techniques Inc 235 Jackson Stree Englewood N J 07631 Prices include ship ping charges inside the United States Complete set of six boards 1 of each GPU BOard a a a cc a eeone Address Latch Board Input Multiplexer Board 1K Memory Board LED Register Display Board Output Ports Board Techniques had 100 sets of boa
42. expected to reach the market soon At present the res olution see photo is not as great as in commercial television cameras but it is hoped that future models may approach and possibly equal broadcast quality Secret of the new camera is the charge injection solid state imager which takes the place of the conventional camera tube The imager a quarter inch square metal oxide semiconductor chip covered with 10 000 pairs of miniature Capacitors does the same job as the camera tube in large television cameras converting a visual image into a video signal WORLD S MOST SENSITIVE TV CAMERA above is Compared in size with a set of keys The resolution is shown in the picture below Each of the pairs of capacitors on the chip is a light sensing device collecting a charge proportional to the light Striking it Scanning circuits then release the charges on each pair of capacitors in jecting them into the base of the chip The imager can be scanned at speeds compatible with ordinary television sets Unlike earlier devices which used charge coupled imagers the signal is not passed from element to element down the scanning line So if a pair of capacitors should fail the result is only a minute dark spot on the screen instead of the darken ing of possibly a whole line Since this miniature camera can be fabricated with current solid state man ufacturing techniques states Arthur M Bueche GE v
43. get started right now by checking the coupon and mailing it today Classroom Training at Los Angeles You can take classroom training at Los Angeles in sunny South ern California NTS occupies acity biock with over tia GENERATOR pees VECTOR MONI OR Fe ma SCOPE SOLID STATE SOLID STATE 2 METER FM TRANSCEIVER AND POCKET RADIO POWER SUPPLY AMFLFIER P COLOR BAR DOT ar i SSE J Pt Et Sry o Ea bakta ED ie cs eng UER T PEPIN sy SIGNAL SOLID STATE GENERATOR a million dollars in facilities devoted exclusively to technical training Check box in coupon Approved for Yeteran Training Accredited Mem ber National Association of Trade amp Technical Schools Natianal Home Study Council SCHOOLS TECHNICAL TRADE TRAINING SINGE 1905 Resident amp Home Study Schools 4000 South Figueroa St Los Angeles Calif 90037 BETTER FM TUNING A stereo multiplex receiver must be tuned very precisely if you want the optimum channel separation and the best signal to noise ratio Two unique circuits simplify tuning in new Harman Kardon receiver THE PERFORMANCE OF MODERN HIGH quality FM tuners and receivers has reached a point of near perfection that generally exceeds the performance of a majority of FM stations broadcast practices There are tuners and receiv ers avallable now that can recover audio programming from the incoming signal at signal to noise ratios
44. important information on the facing page Then fill out and mail the reply card or coupon today We ll send you all the details and for your convenience we will try to have a representative call Act now and get your high paying job just that much sooner How You Can Succeed In Electronics Select Your Future From Seven Career Programs The right course for your career Cleveland Institute offers not one but seven different and up to date Electronics Home Study Programs Look them over Pick the one that is right for you Then mark your selection on the reply card or coupon and mail today In a few days you will have the complete details 1A Electronics Technology A comprehensive program covering Automation Communications Computers Industrial Controls Solid State Devices and prepara tion for a 1st Class FCC License 1B Electronics Technology with Laboratory Includes all areas of Course 1A including 1st Class FCC License preparation In addition student receives 161 piece Electronics Laboratory and 17 lab lessons for hands on experience 2 Broadcast Engineering Here s an excellent studio engineer ing program which will get you a 1st Class FCC License Now includes Video Systems Monitors FM Stereo Multiplex Color Transmitter Opera tion and Remote Control r ye GD G rbd h i Gna Aaa Er a a AHA w te Se ETE rs oe oe gt CAE MG 3 First Class FCC License If a tst Class
45. in Ooto Calculator Components GIANT SALE ON LED S LIGHT EMITTING DIODE GaAs INDICATORS WRIST WATCH ony 19 95 LIQUID CRYSTAL DISPLAY 3 1 2 digit 7 segment g ery TO 18 hak green visible Seaan 1 00 green small dome green diff lite Te f O 2 MV2 clear small plastic dome green diff lite T ioo 7 Only 1 1 16 X 11 16 x 1 4 O 2 MV3 miarospiini fin head dome TO 18 green lite 1 00 see POPULAR ELECTRONICS Jan 197 1 for building L 2 MV3 visible coax pin pak areal mini dome lens 1 00 ba your own electronic digital wristwatch being the Liquid DO 1 MV4 stud high power red watts Fe o A 3 95 Crystal Display LCD as its basic Easy to see 32 Za C 1 MV4H stud high power ce la red 2 watts 3 95 digit display requires less than 1 1000 of power as O 5 MV10B visible red clear dome lens TO 18 a 1 00 LED S Visibility increases with ambient light Difficult 0 5 MV10C visible red diffused dome iens TO 18 eo 1 00 i he Wing al LED Sin light Pulsates SECONDS in center U 5 Mv50 axial leads micro mini dome clear red TO 18 1 00 re display NO NEEN OF TRANSISTOR RESISTOR inter D i MVS an enoaan ail creendeneercen lite 1 00 Gite us LED S thus smaller package Chip contains O MVS3 micro mini axial yellow lens yellow lite 1 00 VAT tiny connecting ferminals and slide in place O S MV54 micro mini axial leads red lens red hie 1 00 a ee spring face pl
46. involved in the muting and stereo threshold switching circuits of the 900 Q208 and Q209 comprise a Schmitt trigger circuit which in com bination with Q210 determines at what signal strength the stereo demodulation circuitry should be turned on V R203 is used to adjust this sensitivity and is accessible to the user from be neath the chassis Q211 and Q212 con stitute a second Schmitt trigger with the voltage at the output of the Zener 49 GEE RATIO DETECTOR VR201 C205 10K Ss xO ii 002 ak IN TUNE LIGHT FIG 5 PARTIAL SCHEMATIC OF HARMAN KARDON 900 showing complete quieting meter and in tune light circuits diode Q217 acting to trigger the cir cuit Sensitivity of this circutt how ever is adjusted independently with a rear panel potentiometer VR204 Thus the user may hear an audio signal with the muting switch in the on posi tion well before the IN TUNE light becomes illuminated If the program is one he desires to listen to he then pro ceeds to tune more carefully until the IN TUNE light goes on otherwise he can quickly pass it by and proceed to the next station which defeats the muting circuit Any other arrangement would have resulted in an extremely tedious and long process when using the muting feature The combination of quieting meter and IN TUNE light indicator on this receiver is vor as might first appear a International friendship theme
47. like the 2SB405 2SB474 and 2SB492 plus a lot of others you ll find in our guide But our cross refetence guide ECG 212E lists a lot more than just audio transistors It lists over 75 000 parts that can be replaced with a minimum number of D Sylvania ECG parts A For you it means one source for practically all your replacement needs including industrial components What more could anyone ask for SYLVANIA GTE Syilvaxa Hecwonic Components Waltham Mass O02154 Radio Electronics THE MAGAZINE FOR NEW IDEAS IN ELECTRONICS More than 65 years of electronics publishing VOLUME 45 NO 7 JULY 1974 SPECIAL 29 FEATURE Build the Mark 8 Minicomputer Your personal home built computer Use an ASCII keyboard input or tie in a TV Typewriter Complete with expandable semiconductor memory by Jon Titus SOLID STATE 38 ELECTRONICS 42 63 How Calculator IC s Work The secrets of these special IC s are uncovered by an expert by Don Lancaster Working With SCR s An experimenter s guide to the device plus a construction project by Brian Bixby R E s Transistor Replacement Guide 2N3554 to 2N3732 compiled by Elizabeth amp Robert Scott GENERAL 4 ELECTRONICS 72 STEREO 7 AUDIO HI FI 23 34 48 58 Looking Ahead Tomorrow s news today by David Lachenbruch Appliance Clinic Battery chargers by Jack Darr Equipment Report Technics by Panasonic SL1200 direct drive turntable
48. measurements for direct Comparison readings pote a 22 FIELD EFFECT MULTIMETER j EH x igs i 1 mr Fik ee Se m f i m ee ee oe me mi M T EE uan PF my E SENC ORE against peak to peak test point voltages labeled on schematics Sensitivity provides eight over lapping voltage ranges between 0 3 volts and 100 volts full scale dc and ac Current range covers dc from 10 mA to 1 amp full scale and five ohm ranges measure resistances from 1 ohm to 1000 megohms 150 00 Sencore Inc 3200 Sencore Drive Sioux Falls S D 57107 Circle 39 on reader service card VHF UHF FM ANTENNAS LPV UC Color Best combine patented log periodic design with ultra sensitive corner reflector and uhf driver for more Sharply detailed reception incolor or black and white on all channels Capacitor coupled dipoles provide synergistic response of vhf channels Staggered multi element phased driver minimizes ghosts and snow on vhf and uhf bands Rugged triple square crossarm construc ARE YOU A PROFESSIONAL TECHNICIAN If you are experienced and well trained as an electronics service technician why don t you let someone know about it Become a Certified Electronic Technician You will need 1 4 yrs experience and or schooling 2 2 to 4 hrs time to take the exam 3 10 00 exam fee write for more info and dates of exams NAME ADDRESS S City STATE ZUIP_ PHONE mail to ISCET 1715 Expo
49. meter movements and a peak signal indicator lamp As long as the meter shows the prog ram Is below 0 VU and the peak signal indi cator is not flashing the input signal is being recorded undistorted The value of this professional calibration is immediately ap parent upon listening for combined with the ANRS the CD 1668 can turn out a tape copy of a record indistinguishable from the original The optical eject is one of those ideas that takes time to appreciate In the typical auto eject system a mechanical device is activated when the tape is stretched as it reaches the end of the reel Though the tape has run out the applied capstan drive causes the tape to stretch and an arm riding on the back of the tape senses the stretch after afew seconds either the motor is stop ped or the eject mechanism is activated The optical eject avoids the tape stretch by using a shutter generated signal to con trol an eject solepoid The reset counter is continued on page 86 10MHz 5 scope with easier calibration and voltage measurement AAS m i 7 1 Model 1465 400 Here are some B amp K extra touches Besides DC to 10MHz bandwidth triggered sweep automatic sync 16 6mV cm vertical sensitivity DC coupled amplifier and front panel Vectorscope capability Model 1465 also has 5X magnification to increase sweep speed to0 2usec cm for complex waveform analysis And Cali Brain which collapses horizontal
50. off This happens if the blanker coupling capacitor opens or the blanker tube goes dead Key clues low plate voltage on color difference amplifier tubes along with low cathode volt age and absence of blanking pulse on cathode with scope In another set of about the same vintage RCA CTC 38 etc the blanker tube is ac tually in series with the picture tube bias control which varies the de supply to the picture tube grids It does this because the control is in the de supply line to the color amplifier plates Figure 2 shows this version Note that there is a de path for current from the bias control through the plate cathode circuit of the blanker tube and then on to ground actually completed through the cathode resistor of the 2d color bandpass amplifier if the blanker tube goes dead this will upset the de voltages They will go higher more positive and the picture tube grids will 69 _ ele flatic NY COLOR ACCESSORY KIT PA 222 KIT CONTAINS CR 280 S cR 115 REPLACEMENT SOCKET CR 90 110 TUBE TEST ADAPTOR m CR 110 90 CHASSIS SERVICE ADAPTOR SERVICE EXTENSION AVAILABLE INDIVIDUALLY FREE Reference Charts e elllatic Brooklyn N Y 11207 70 Circle 16 on reader service card follow This will overdrive the picture tube and the raster will flare up In some sets the raster will flare up then go dark This is due to the overload on the high v
51. or distantly placed component identifications and puzzling schematic layout 5 Updating This is a serious problem One manufacturer has put out schema tics for early production and another set for late production models The hitch is that the technician may not have any way of knowing which he is working On Or he may even be servicing a hybrid with some early and some late features For efficient servicing it is necessary that whenever production changes are made the chassis number be modified and the service data be modified to correspond in such a way that the technician can be sure he has the correct data for the set 6 Availability of data It should be pub lished available and mailed to subscrib ers prior to the date the product appears on the market 7 Photographs pictorials and draw ings Each component service adjust ment and control must be identified in both photos and drawings Also included should be all mechanical tuner parts drive assemblies dial stringing diagrams and cabinet parts including knobs R E nician It requires ourselfers e a TV service tech go ll y r TV set Se ing more money it takes MO know how espe actually do more for repairs OF ad tocal TV technic is et Tinkenn Se ependent TV technician bgt first gn O n at that urs an be dangerous a wW for safety as well as dontp f trouble 50 sive Call your atisfaction AGUE PROD WET mam AL T z A
52. purchase 1 00 304 Negative Voltage Regul TO 5 1 25 ea 305 Positive Voltage Regul TO 5 1 25 ea 3002 LSI simifar to 001 exc des for battery 307 Op AMP super 741 MINI DIP TO 5 45 ea operated Data supplied with chip 8 95 ea 308 Micro Power Op Amp MINI DIP 1 25 ea 309H 5 V Regulator TO 5 1 25 ea Data only Refundable with purchase 1 00 309K 5V 1A Regulator 10 3 1 2 ea l pee 310 Voltage Follwer Op Amp TO S 1 45 ea 5005 LS 28 pin Full 4 funct mem 12 dig displ amp 311 He pert Volt Compartr MINI DIP TO 5 1 25 ea calc 7 seg mitplx outp Data suppl w chip 10 95 ea 319 Hi Speed Dual Compartr DIP 165 ea re a h 320 5 2 V Neg Regulator TO 3 1 95 ea Data only Refundable with purchase 1 00 320 15 V Neg Regulator 103 1 95 aa MM5736 18 Pin 6 dig add subtr mult div 4 95 ea 324 Quad Op Amp DIP 2 25 ea ai m haai 7 339 Quad Comparator DIP 2 50 ea 340T Pos Volt Reg 5 5095 6V 8V 12V 15V 18V 24V TO 220 25 ea DIGITAL CLOCK CHIPS 370 AGC Squelch AMPL TO 5 or DIP 1 65 ea 372 AF IF Strip detector DIP 85 ea MM 5311 28 pin any readout 6 dig BCD 373 AM FM SSB Strip DIP 3 60 ea with spec sheet 11 95 ea 376 Pos Voit Regulator MINI DIP 65 ea 377 2W Stereo amp DIP 2 75 ea MM 5332 24 pin any readout 4 digit Ipps output 380 2 Watt Audio DIP 1 75 ea BCD with spec sheet 8 95 ea 380 8 6W Audio amp MINI DIP ee ea MM 13 28 3 6d 38 Low Noise Dual Pre Amp DIP 25 ea A O A aik 10 95 ea 382 Low Noise Dual Pre Amp DIP 2 25 ea
53. rise time less than 100 ns at 20 kHz symmetry balanced within 5 or less LAB GRADE PERFORMANCE is claimed for the Leader L80 505 5 inch solid state dual channel scope Triggerend and automatic sweep with speeds adjustable in seventeen steps from 1 ps cm to 0 5 s cm Sweep also continuouly variable over the same range Pre set positions for syncing to TV vertical and horizontal scanning rates Has X10 sweep magnification Sweep trigger selection alter nate chopped or channel 1 or 2 Internal or external on or slope Ac or de coupling on each vertical channel dc to 15 MHz bandwidth 10 mV cm sensitivity adjustble to 5 Vp p cm in nine calibrated steps Rise time 35 ns Input impedance 1 megohm shunted by 40 pF 10 megohms shunted by 10 pF or less with 10 1 prone Takes external 15 Vp p negative polarity signal for intensity modulation A panel control provides continuous scaie illumination A 0 5 Hi FI Test Instruments than it was just a few years ago and you ll need lab grade Learn what instruments you ll need and how they re used iC ae o 0 e 6 aa Vp p square wave calibrating voltage is avail able at a jack on the front panel IM AND THD ANALYZER includes sensitive audio vtvm and dB meter The Eico 902 uses a continuously variable 20 20 000 Hz Wien bridge rejection filter for harmonic distortion measurements IM distortion measurements are made with 60 Hz and 7 kHz signals mixe
54. sociated logic will be refered to as the cen tral processor unit or CPU Phe central processor unit is an amp bit parallel processor A string of eight binary bits D through Do is used to indicate the Instruction data or memory locations Rather than repeat eight bits of binary data we refer to the eight bits as a byte As vou will note some of the instructions take up to three bytes of data and they are therefore called three byte instructions The computer takes 20 us to execute each byte of these instructions so the time to execute any of the basic instructions may vary from 20 to 60 us The time that the computer takes to execute one byte of the Instruction is culled the computer s cycle time Most minicomputers have a cycle time that is about ten times faster than the Mark amp 8 but this will not restrict the use of this Minicomputer in most situations The Intel 8008 microprocessor provides us with some sophisticated features only found on larger more costly computers These include a pointer register interrupt pointers and a stack register for multiple subroutines Fhe Mark 8 is programmed in assembly or machine language the basic language of all computers which consists of Is and 0 s grouped into bytes While it may seem cum bersome at first this is one of the most Ilex ible ways to program while keeping down the cost of added storage or memory The use of just the I s and 0 s to represent the binar
55. sweep to let you measure instan taneous peak to peak voltage easily while simulta neously displaying the full scale voltage range Now in stock at your local distributor or write Dynascan PRODUCTS OF I DYNASCAN 1801 W Belle Plaine Ave Chicago IL 60613 312 327 7270 Circle 14 on reader service card 26 Your time is prime waste it checking ages when youcan ing time in half with sion Analyst Its fiy transforms the 3 x4 ency we provide into a injection outputs for every stage from the flyback all the way back to the antenna terminals Pinpoint problems in minutes not hours There s a dot bar crosshatch genera tor for color too Unique In stock at your distributor now or write Dynascan test pattern in prime time time So why dozens of volt a aa cut troubleshoot i our 1077B Televi ing spot scanner eS ee test pattern transpar Ss standard TV signal with PRODUCTS OF DYNASCAN 1807 W Belle Plaine Ave Chicago IL 60613 312 327 7270 Circle L15 on reader service card Better electronic service data is aim of ISCET study According to the International Society of Certified Electronic Technicians ISCET Serviceability chairman Dean R Mock three ingredients are necessary to the efficient repair and service of elec tronic products 1 A product designed to be service able 2 Availability of proper service parts 3 Proper Service Data NESDA the paren
56. that project Then turn to that company s listing for their com plete address and details on what they offer VINTAGE RADIO second edition by Harold Greenwood Revised Edited and Expanded by Morgan E McMahon Vintage Radio Box 2045 Palos Verdes Peninsula Calif 90274 8 1 4 x 5 1 4 in 264 pp Softcover 4 95 Hardcover 6 95 A pictorial history of wireless and radio covering the period from 1887 to 1929 This is the story of one of mankind s great achievements the ability to talk across the miles to one person or to millions of people This authoritative collector s and historian s handbook contains photos and information on more than 100 items As you turn the pages you can recapture the feel of pioneer days of wireless and radio You will be browsing through old time ads pictures and trivia FET CIRCUIT BOOK G C Electronics Co 400 South Wyman Street Rock ford til 61101 5 1 2 x 8 1 2 in 14 pp Softcover 25c Provides the hobbiest and experimenter with a basic understanding of how the FET works and a number of interesting circuits Each of the nine projects is complete with parts list and ali other information needed to duplicate the device SOLDERLESS IC PROTOTYPING TECHNIQUES by Cari T Helmers Jr M P Publishing Co P O Box 378 Belmont Mass 02178 7 x 10 in 76 pp Soft cover 4 95 The techniques and methods described in this manual are meant to inform the reader about methods of electronic prototype construct
57. third dimension in NRI training practical experience Train with the leader NRI Compare training kits texts techniques and overall training and you ll find that you get more for your money from NRI Whatever your reason for wanting more knowledge of Electronics NRI has an instruction plan that will meet your needs Choose from major programs in Advanced Color TV Servic ing Complete Computer Electronics Industrial Electronics and the other special courses designed to meet specific needs With NRI home training you can learn new skills while you re still working at your present job and turn yourself into the man in demand GET FACTS ABOUT GI BILL If you have served since January 31 1955 or are in service now check GI line on postage free card Send for free NRI catalog MAIL THE POSTAGE FREE CARD FOR THE FREE NRI CATALOG IN THE FIELD OF YOUR CHOICE YOU WILL BE UNDER NO OBLIGA TION NO SALESMAN WILL CALL If the card has been used write direct to NRI TRAINING E 3939 Wisconsin Ave Washington D C 20016 11 E 1Ie2 W Er ti mely continued from page 6 Compact solid state TV camera can work by candle light The world s most sensitive TV Ccamera capable of taking pictures by the glow of a candle weighs less than a pound and is more compact than most photographic hand cameras Developed at the General Electric Re search and Development Center Schenectady N Y it is
58. tions caused by variations in supply voltages to the drive or capstan motors or gradual changes in take up tension continued on page 76 struments at the same time Lets say that you ve decided on I a sine squarewave audio generator 2 a sweep and marker generator especially for FM work the shop s sweep marker generator is always tied up on the TV ser vice bench 3 an FM stereo multiplex generator and 4 an AM rf signal generator for AM radio work In this case you d want to look closely at something like Sencore s SG165 AM FM Stereo Analyzer It re places the functions of the four instruments you want while including such goodies as dual 100 watt speaker dummy loads and two wattmeters with I0 and 100 watt ranges The same type of thinking can be applied to your equipment needs and other types of all in one instruments As you gain experience in hi fi servicing you may find a need for such instruments as a tone burst generator X Y recorder or an electronic counter And you will accumulate such accessories as test records test tapes stylus pressure gauges stylus microscopes and head cleaners and demagnetizers for reel to reel cassette and cartridge tape equipment You ll be working with high quality gear so purchase the best equipment you can afford ar 2 a m bas say o Mue i ee a l ARI T F O m H oH i m se i i ear m You have a wide choice of instrumen
59. to the video detector test point or anywhere else after the video detector diode and the demodulator probe to the bandpass amp ifier output They re all clip on connections and the 415 comes with all the accessories need Once I ve made the initial signal and bias hookups there s nothing else to connect or reconnect All intercabling changes and generator functions are controlled from the front panel There s even a 15 750Hz filter to eliminate disabling PRODUCTS OF i 9 DYNASCAN 1801 W Belle Plaine Ave Chicago IL 60613 Phone 312 327 7270 Model 415 440 the set s horizontal output section Shaping the waveform is easy because the 415 has 10 crystal controlled IF markers each of which lights up on the front panel waveform diagram as it is used Markers can be shown either vertically or horizontally on the scope trace There s a 100kKHz modulated mark er that makes nulling the traps so easy it s almost automatic And three low impedance reversible polarity bias supplies two 0 25VDC one 0 50VDC CHROMA 42 17 ADJ PIX 39 75 Vertical Markers Markers Tilted Horizontally Every step is easy to understand too thanks to the comprehensive manual Since have nothing to sell but my time have to make the most profitable use of it can That s why have a B amp K 415 In stock now at your focal distributor or write Dynascan Complete Line of Analog and Digital Multimeters Osci
60. treat the instruments as if they owned them RCA hopes to gather data on the suitabil ity of the machine under ac tual home use and the reac tion of potential owners R E by David Lachenbruch Contributing Editor TUNER SERVICE CORPORATION PROVIDES YOU WITH A COMPLETE SERVICE FOR ALL YOUR TELEVISION TUNER REQUIREMENTS VHF Or UHF Any Type 9 95 UHF VHF Combo 15 00 In this price all parts are included Tubes transistors diodes and nuvistors are charged extra Fast efficient service at our conve niently located service centers This price does not cover mutilated tuners All tuners are cleaned ultrasonically repaired realigned and air tested Universal Replacement In Canada 14 95 This price buys you a complete new tuner built specifically by SARKES TAR ZIAN INC for this purpose All shafts have a maximum length of 10 which can be cut to 142 Specify heater type parallel and series 490mA or 600mA Customized tuners are available at a cost of only 15 95 In Canada 17 95 15 95 Send in your original tuner for com parison purposes to TUNER SERVICE CORPORATION Backed by the largest tuner manufacturer in the U S SARKES TARZIAN Inc HEADQUARTERS BLOOMINGTON INDIANA 47401 ARIZONA TUCSON ARIZONA 85713 CALIFORNIA BURLINGAME CALIFORNIA 94010 CALIFORNIA MODESTO CALIFORNIA 95351 CALIFORNIA NORTH HOLLYWOOD CALIF 91691 F
61. use a one of N de coder to provide supply power or digit line power to Only one entire numeral at a time Thus while all the digits know what the numeral is to be only one of them receives supply power at any single in stant and only one of them lights at a time We bring the digits information out one digit at a time and at the same instant we step and decide which digit line gets power The result is a sequence of digits being lit The sequence repeats so fast that you see everything aS a continuous display One very handy circuit saving trick the calculator people use is that they sequence the digits at the same rate they do the calcula tions and in the same order thus our digit sequencing is essentially free as the numbers have to go around anyhow when a calcula tion is being made When a calculation is NOT being made the numbers still go around but the internal arithmetic unit more on this in a bit goes into a do nothing mode and does not change the contents of the display or answer register that is Storing the number being output Multiplexing needs a display system that has internal diodes thresholds or nonlinearities If the system was perfectly linear you would get sneak paths through series combinations of supposedly off segments causing ghosting and other problems Light emitting diode displays are inherently diodes and eliminate the problem as do the nonlinearities associated with fluorescent displays Panaplex
62. ver sion of an old technique in the near future e i Adding up calculators The electronic calculator became a billion dollar market at retaillast year according to a study by Creative Strategies The biggest share of the mar ket was held by consumer cal culators of which 7 million were sold Some 3 5 million of last year s unit sales were bus iness calculators and another 300 000 were in the profes sional category The study indicated that the market for consumer calculators would grow about 50 this year in terms of dollar volume more in terms of units due to de clining prices Component costs for calculators have dropped sharply LC chips fal ling from an average of 30 in 1970 to about 5 currently LED displays which cost cal culator manufacturers slightly less than one dollar per digit will be closer to 50 cents be fore the year is over e a ae RCA s home VTR i EE ee RCA meanwhile has em barked on a market test of its 34 inch cartridge VTR to de termine whether it has poten tial as a Consumer product In the initial phase demonstra tions are being conducted by television retailers Observers at the demonstrations are asked to fill out a question naire designed to determine their interest in purchasing the device The second phase of the test starting this sum mer will involve loans of VTR s and monochrome cameras to about 200 selected consumers who will be asked to
63. your Organ is finished lifelike big auditorium reverberation automatic rhythm presets chimes and more Circle 61 on reader service card Circle 66 on reader service card Join the thousands of Schober Organ builder owners who live in every state of the Union Often starting without technical or music skills they have the time of their lives first assembling then learning to play the modern King Of Instruments through our superlative instructions and playing courses Get the full story FREE by mailing the coupon TODAY for the big Schober color Catalog with all the fascinating details the Schober Organ Corp Dept RE 128 5 43 West 61st Street New York N Y 10023 i Please send me Schober Organ Catalog i O Enclosed please find 1 00 for 12 inch L P U record of Schober Organ music fname I ADDRESS I e gcity STATE Ps A a oo h college level trainin x all z i E f ale il i Ppr et Se oe Ret Ee BS program which gives you in electronic circuit design Electronic circuit design source of all new development in the application of electronics to new products and services Without this skill we would be unabie to monitor the heartbeat of men in space Without it the computer revolution would never have occurred And we would have yet to see our first TV show Yet only CREI teaches electronic circuit design at home ELECTRONIC CI
64. 1 just out MINIMUM ORDER 5 00 Gregory Electronics Corp ENIE E 96 XI International Electronics Unlimited 95 i m a i S4 JTM Associates oh 6 Lakeside Industries s a OR Lesco Electronics l l e94 a Logic Newsletter gt fess 98 R2 Meshni Electronics John Jr 93 BOX 1 LYNN MASSACHUSETTS 01903 Potolume Corp 2 2 2 m ss 83 Poly pitks 2 im R Phenei GE ge ein n Solid State Sales ee 98 Circle 80 on reader service card 10 POWER TAB SCR S With Tremolo SoLip STATE ter v low priee Peak j P Aiie ra ae ee el Pea circuits are Saya h k power a dal al or solo guitar The four rontrols nne j lt of ee gins TONE TREMOLO INTENSITY and i ghee it gt EA There are terminals on hoard for Le SA mor a vis s Only 35 fant pee connection Supply voltage h Jens J f 9 2 hm hi qguality speaker Input impes dit e y a lt git rent drain 20 mils External power s Dp eo ate 1 th With instructions hookups and TAE ah Size R x 25g x A 40 mils Size 7 x 315 a Buy Any 3 Take 10 1210 Zine O t1r03 12513 C 2516 7489 Gis 8225 MM552 Rit RASNI MOS 02 4 Bir RAM MOS Character Cen ROAM haracter Gen ROM Ha Bit RAM TTL rorrinim ible l bhit rened or re pP AMP PLASTIC 6 95 12 50 12 50 2 95 hi ROAD Write 50 P AM2 95 L 12 50 8 WATT STEREO AMP ak STATE Ty
65. 1 1641 DA 1503 738 0001 g i co aoa 449 9794 MO ivvl 1816 7370066 tx oN E214 234 4137 And they re precise Measurements Approximate cy 703 525 747 Mo 164 a ni zmn TX 15 T aeee Fie 1933 94 5815 A 19 S558 E01 1 ly 5 t 10 times more accurate Ihan what you It get GA agai 457 7147 WJ 51 7151975 R711 WA 7061 7692710 from an analog meter And a great deal easier to read Ht IROA 262762786 NJ iw 201 8635660 Can w aig 787 1208 Th 1312 59530252 HbA 1505 264 6471 CAN W 1613 777 5874 Model 134 measures DC and AC volts OC and Data Precision Corporation Audubon Road Wakefield MA 01880 617 246 1600 ara PRECISION years ahead Circle 74 on reader service card FREE 74 CATALOG Fast Flameless CONCENTRATED HEAT up to 1000 F 2 gt CONCENTRATED Hear Up to 1000F Flameless Fast Portable HEAT BLO GUN The Heat Gun of a Thousand Uses A model for every need ranging from 150 to 1000 F without an open flame Safe and easy to operate use wherever concentrated heat is needed Fingertip switch control permits operator to aim heat right at desired point Temperature can be varied by air intake adjust ment Also blows cold air when desired MEETS DOZENS OF NEEDS in laboratory and on production lines softens plastics dries paint glue or photo prints thaws _ defrosts heat seals does blister packs preheats for welding or soldering desoldering excellent for softening repairin
66. 2 a XC22Y ex cept yellow clear lens al FACTORY FALLOUT _ 1 49 EA luminator use 24 angle 4 FUNCTION MEMORY XC 556Y a XC22Y except vellow diffused lens indi CALCULATOR KIT O eator use 40 view angle A Pochet type the lowest price 4 funetion memory with all arithmetic Com a plete with all parts instruction Booklet j Terms add postage Rated net 40 Phone Orders Wakefield Mass 617 2415 3829 vt Retail 16 18 Del Carmine St Wakefield Muss off Water Street COLS MAY Bk PHONED t5 CATALOG on Fiber Optics iCs Semis Parts POLY PAKS P O BOX 942R LYNNFIELD MASS 01940 Put Your Trust In Poly Pak s Money Back GUARANTEE 97 service card gue neeuioine evantes a ADVERTISING INDEX With Lakeside Industries re building equipment you can rebuild any pic PROFITABLE ONE MAN ELECTRONIC FACTORY Investment unnecessary knowledge not ture tube required sales handied by professionals For complete details RADIO ELECTRONICS does not as Ideal home business Write today for Ode send name address zip sume responsibility for any errors B Bo code to me ta 4 3 J Bea eee cA Basan fe PG Box 448 H Canesioe mouses al which may appear in the index 1 z 3520 W Fullerton Ave Chicago IIi 60647 below OIGITAL THEORY DESIGN Phone 312 342 3399 CONSTRUCTION LOGIC READER SERVICE CARD NO PAGE NE SL
67. 2 00 Ea Motorola 24D66926A07 2 00 Ea DIODES TRANSISTORS 25 IR 2 5 Amp 1000 PIV 4 9 100 IR 2 5 Amp 1000 PIV 16 9 6500 FOCUS RECT aueues secs 4 for 2 00 13 5 KV Focus Rect 5 for 3 00 25 1N34A Crystal Diodes 2 09 5 Color Boost Rect 4ge 250226555 2 00 COLOR FLYBACKS ROA 2745 oa A 7 95 Ea REA S664 0 ee ee eee aes 7 95 Ea EMERSON 738229A 3 95 PHILCO 32 10132 1 2 2 3 95 10 Asst d Align Tools 1 98 TUNER CLEANER SPRAY 8 O2 1 00 50 Asst d W W Resistors 27 99 20 Asst d MALLORY CONTROLS 2 00 SLIDE SWITCHES ASST D 10 for 1 00 DELAY ININES saree see reece 2 for 1 19 25 Asst d Terminal Strips 1 00 20 Asst d Tube Sockets 1 00 CRT Harness COLOR 5 for 2 00 CRT Harness B W 3 for 1 00 7 amp 9 Pin Tube Sockets P C 20 for 1 00 R F Cables Tinned Ends 6 for 1 00 Shunt Reg Hoods 2 for 1 00 50 Asst d IF Xfmrs Rad TV FM 2 49 100 Asst d MICA COND 1 19 CONDENSERS CANS 300 Mfd 200 Volts 4 for 7 29 400 Mfd 200 Volts 4 for 2 59 30 20 10 Mfd 350 V 1 Can 4 for 1 00 40 20 Mfd 150 Volts P C 9 for 1 00 200 Mfd 80 Mfd 350 V 3 for ae ee 25 Asstd Filters vane ate nee 1500 Mfd 50 Volts 3 for i 38 CONDENSERS AXIAL LEADS 100 Mfd 150 Volts 10 for 1 98 500 Mfd 25
68. 3 PTC 103 PTC 103 PTC 110 PTC 110 PTC 103 NA PTC 121 PTC 126 PTC 136 PTC 126 PTC 152 PTC 152 PTC 152 PTC 152 PTC 121 PTC 121 PTC 121 PTC 121 PTC 121 PTC 121 PTC 121 NA NA NA NA NA PTC 144 PTC 127 PTC 103 PTC 136 PTC 136 PTC 136 PTC 139 PTC 139 PTC 139 PTC 139 PTC 139 NA NA NA NA NA PTC 142 PTC 142 PTC 153 PTC 110 PTC 110 PTC 110 PTC 110 PTC 127 PTC 127 PTC 121 PTC 121 PTC 122 PTC 122 PTC 122 MOT HEP R1301 HEP R1302 HEP R1304 HEP R1306 HEP R1307 HEP 53021 HEP 242 HEP 242 HE P 56 HEP 56 HEP 714 HEP 714 HEP 704 NA NA NA HEP 51 HEP 57 HEP 57 HEP S3002 HEP S3002 HEP 52 HE P 3001 HEP 728 HEP 709 HE P 56 HE P 709 NA HEP 729 HEP 734 HE P 729 HEP 729 HEP 729 HEP 803 HEP 803 HEP 803 HEP 803 HEP 714 HEP 714 HEP 716 HEP 57 HEP 735 HEP 55 HE P 55 HEP 723 HEP 732 HEP 55 HEP 55 HEP 55 HEP 714 HEP 247 HEP 704 HEP 247 HEP 704 HEP 242 HEP 242 HEP 54 HEP 714 HEP 714 HEP 714 HEP 714 HEP 716 HEP 716 HEP 729 HEP 729 HEP 234 HEP 235 HEP S5005 RCA NA NA NA NA NA NA NA NA SK 3039 SK 3018 NA NA SK 3036 NA NA NA SK 3025 SK 3114 SK 3114 NA NA SK 3025 NA NA NA SK 3039 NA SK 3112 SK 3112 SK 3112 SK 3112 SK 3039 SK 3039 SK 3018 SK 3018 SK 3124 SK 3122 SK 3122 NA NA NA NA SK 3045 NA SK 3114 SK 3114 SK 3024 SK 3124 SK 3025 SK 3124 SK 3124 SK 3124
69. 4 SK 3018 SK 3018 SK 3018 NA NA NA NA SK 3114 SK 3114 SK 3114 SK 3114 SK 3021 SK 3021 SK 3021 NA SK 3006 NA NA NA SK 3018 SK 3019 SK 3019 SK 3019 NA SK 3009 SK 3009 SK 3009 SK 3009 SK 3009 SK 3009 SK 3009 SK 3009 SK 3039 SK 3025 SK 3118 SK 3114 SK 3018 SK 3122 SK 3124 SK 3114 SPR NA RT 108 RT 108 RT 102 RT 102 RT 114 RT 114 RT 114 RT 113 RT 113 RT 115 RT 115 RT 115 RT 115 RT 128 NA NA NA NA NA NA NA NA NA NA NA NA RT 113 RT 102 RT 102 RT 102 NA RT 127 RT 127 RT 127 RT 127 RT 127 RT 127 RT 127 RT 127 RT 113 RT 115 RT 115 RT 115 RT 102 RT 102 RT 102 RT 115 RT 115 RT 102 RT 100 RT 113 SYL NA ECG 107 ECG 107 ECG 123A ECG 123A ECG 128 ECG 128 ECG 128 ECG 108 ECG 108 ECG 108 ECG 106 ECG 159 ECG 159 ECG 159 ECG 159 ECG 124 ECG 124 ECG 124 NA ECG 160 NA NA NA NA NA NA NA NA ECG 108 ECG 123A ECG 1234 ECG 123A NA ECG 121 ECG 121 ECG 121 ECG 121 ECG 121 ECG 121 ECG 121 ECG 121 NA NA NA NA NA ECG 159 ECG 159 ECG 123A ECG 123A ECG 123A ECG 159 ECG 129 ECG 123A ECG 123 ECG 108 ECG 5501 WOR WEP 712 WEP 720 WEP 720 WEP 55 WEP 55 WEP 736 WEP 736 WEP 736 WEP 56 WEP 709 WEP 709 NA NA NA WEP 52 WEP 52 WEP 52 WEP 52 WEP 53052 WEP 3021 WEP 701 WEP 701 WEP 736 WEP 3 WEP 3021 WEP 53021 WEP 3021 WEP 53021 WEP 3021 WEP 53021 WEP
70. 40 SCREWS and 100 5 40 HEX NUTS 1 500 ASSOATED RIVE S most useful ve 1 lected sizes 300 ASSORTED WASHEAS most useful se 1 lected szea 100 ASST RUBBER BUMPERS for cahi net battoma other uses 100 ASSORTED RUBBER GROMMETS Hest 8 sizes 5 10K 2 WATT BIAS POTS sed in solid state application 12 UNIVERSAL SPEAKER Top Qualits A A9 Large Magnet 10 PHILCO SPEAKER Top Quality 2 99 pi Magnet 8 UNIVERSAL SPEAKER Large 2 99 Magnet Special Ruy 1 29 4 UNIVERSAL TWEETER 1 oz Magnet UNIVERSAL 4 PM SPEAKER 1 Top Qual ty 217 x 4 SPEAKER Special Buy 10 c Es For 5 a 6 4 X 6 QUAM 16 OHM SPEAKER ie e magnet Spenal BUY 10 for 1 79 RONETTE STEREO CARTAIOGE latest dual 2 sapphire flipover type STEREO HEADPHONES Hi Fi Quality a 95 Complete with Stereo plug 10 STANDARD TRANSISTORS NIN amp 8 PNP 2N404 2N414 ete UTAH 8 HEAVY OUTY t0 O2 9 95 SPEAKER Ceramic Type R Ohm TUBE amp CONTINUITY CHECKER Made FT424 Tests fuses heaters lamps 1 98 Ete 2 FRAGIL ELEC CONDENSERS 40 30 4 1 Mfd 475 2 ELECTROLYTIC CONDENSERS 2 31 4 8 mfd 350V 8 TRACK TAPE PLAYBACK ay A 50 Campact design fits anywhere 1 3 ELECTROLYTIC CONDENSERS 100 mfd 100 V 50 mfd 75 32 TEST PROD WINE DELUXE QUALITY red amp black SOLID STATE UHF CONVERTOR hans 7 95 nels 14 83 easy to instal VARCO STEREO CARTRIOGE CW 72 95 With mounting brac
71. 4178 40 74185 475 7486 37 74H21 37 74H22 37 74H30 37 74H40 a 74H50 37 74H52 37 74H53 69 8214 69 8220 69 8230 69 8301 1 55 8309 1 05 8312 1 75 8520 250 8551 2 95 8552 3 95 8554 65 CD4013 65 CD4016 1 00 CD4017 65 CD4019 65 CD4022 65 CD4023 256 bit RAM MOS 1024 bit RAM MOS 1024 bit RAM Low Power 64 bit RAM TTL Programmable ROM MEMORIES o 55 65 55 1 15 69 95 40 60 60 60 60 89 B0 25 ao _ 37 37 NNN e a e d ee N aea VOOROONWwWY Wun 85 74C 74 1 50 85 74C76 1 70 95 74C107 1 50 95 74 151 2 90 85 74C154 3 50 85 74C157 2 25 74C160 3 30 74C161 3 25 74141 74145 74150 74151 74153 74154 74155 74156 74157 74161 74163 74164 74165 74166 74173 74175 74176 74177 74180 74181 74182 74185 74190 74191 74192 74193 74194 74195 74196 74197 74198 74199 74L90 74191 74193 74L95 741164 74L165 74L98 74H55 74H60 74H61 74H62 74H72 74H74 74H76 8810 8811 8812 8822 8830 8831 8836 8830 74C762 74C163 74C164 74C173 74C192 74C195 80C97 1 50 CD4025 1 50 CD4027 2 95 D4030 1 35 CD4035 2 75 65 gt N N Aa A AS Se SS Ss a oe st aad OOwOenuwnuwrsl Ss ONNEN MVA VN DNDN KNN Sa e ee DoOoONNWN Wing UFO Ww 45 45 45 45 60 70 70 95 1 25 2 95 25 2 95 69 1 50 65 1235 65 2 85 2 50 7 95 7 95 3 25 6 95
72. 451 Dual Peripheral Driver MINI DIP 39 ea 75452 Dual Peripheral Driver MINI DIP 49 ea MCA 2 30 Darlington 95 ea 735453 351 Dual Periph Driver MINI DIP 69 ea A 75491 Quad seg driver for MCD 2 Diodes 1 95 ea LED readout DIP 1 60 ea MCT 2 Transistor 1 45 ea 75492 Hex digit driver DIP 1 75 ea Circle 81 on reader service card 1 25 ea 6 for 5 00 2 75 ea 6 for 15 00 LINEAR INTEGRATED CIRCUITS MAN3A type 7 seg 127 1 40 ea DL707 type Mana 1 Repl CALCULATOR CHIPS Please specify which data sheets are required with order Add 50 per data sheet for items priced less than 1 00 each PHASE LOCKED LOOPS Type red 7 segment 270 Type red 7 seg 127 1 75ea Type red 7 seg 190 2 35 ea Type grn 7 seg 270 4 75 ea Type SLA1 red 7 seg 2 50ea ype yel 7 seg 270 5 50 ea Type MAN 1Repl 3 50ea 3 95 ea 4 4 85 4 7 95 4 15 75 4 7 95 4 18 95 4 13 00 MASTER CHARGE AND a BANKAMERICARD ACCEPTED tinniutmtano BY MAIL OR PHONE Supply all card numbers and bonk some Minimu m cho g ordar 510 00 Phone orders Monday through Fridoy 100G om 400pm 408 6394773 ON ORDERS OVER 25 00 DEDUCT 10 All items are new unused surplus parts tested functional Satisfaction is guaranteed S
73. 5 Piansistorized 3 TV TUNER Tess Lubes ee GE TV TUNER FT 86X196 60 K5 6B1 8 RCA COLOR POWER TRANS FORMER 26R1S0 Good for most sets List 36 75 CO AX CABLE R amp s59L hlack 740 59 1V 2 ELECTROLYTIC CONDENSERS 10075 mfd 3I00V TO intdel N ar 2 ELECTROLYTIC CONDENSERS 300 mid 200 V 200 V 300 60 mtd 1 S00 V IMMEDIATE DELIVERY HANDY WAY TO ORDERS 37 7 95 A oF 3 69 SO i MARKET SCOOP COLUMN R a y a a E KLEPS CLEVER TEST PROOS Third hand test prods reach into out of way places accommodates plug ono soldering 7 BRUF 10 VERSATILE TEST a9 PROBE _ KLEPS 10 BOATHOOK CLAMP 9 39 4 lon ial KLEPS BOATHOOK CLAMP 4 49 ee on G KLEPS 30 FLEXIBLE FORKED 4 79 TONGUE 6 lon KEEPS 40 FLEXIBLE PC BOARD 9 59 TERMINALS 6 lon KLEPS 1 ECONOMY KLEPS FOR LIGHT WORK CVE CES Sie Eee ee 3 ae sla def D Scientifiz _ Send check or money order add extra for shipping Lists of new offers will be returned in your order WESTINGHOUSE ALL SISTOR HOME OFFICE MESSAGE CENTER leaves messages for other for replay Built in speaker microphone for talk into convenience cords up to 3 minutes of messages signal shows when a message volume Capstan Drive BRAND NEW SOLD AS IS ZENITH COLOR OEMOOULATOR CHIP PART 2221 39 Sprague Fay TVC M 3 95 1 BLUE LATERAL MAGNET ASSY Re 1 59 placement for most color TV s UNI
74. 58 2N3659 2N3660 2N3661 2N3662 2N3663 2N3665 2N3666 2N3667 2N3668 2N3669 2N3670 2N3671 2N3672 2N3673 2N3675 2N3676 2N3677 2N3678 2N3680 2N3681 2N3682 2N3683 2N3684 2N3685 2N 3686 2N3687 2N3688 2N3689 2N3690 2N3691 2N3692 2N3693 2N3694 2N3695 2N3696 2N3697 2N3698 2N3700 2N3701 2N3702 2N3703 2N3704 2N3705 2N3706 2N3707 2N3708 2N3709 2N3710 2N3711 2N3712 2N3713 2N3714 2N3715 2N3716 2N3719 2N3720 2N3721 2N3722 2N3723 2N3724 2N3725 2N3726 2N3727 2N3728 2N3729 2N3730 2N3731 2N3732 ARCH NA NA NA NA NA NA NA NA RS276 201 1 RS276 2011 NA NA NA NA NA NA RS276 2021 RS276 2024 RS276 2024 NA NA RS276 2023 NA NA NA RS276 2001 NA NA RS276 2013 RS276 2013 RS276 2013 NA RS276 2013 RS276 2013 RS276 2013 NA NA NA NA NA NA RS276 202 1 RS276 2024 RS276 2009 RS276 2009 RS276 2009 RS276 2009 RS276 2009 RS276 2009 RS276 2009 RS276 2009 NA RS276 2025 RS276 2025 RS276 2016 NA NA NA NA NA NA NA NA NA NA NA DM SR 1301 SR 1302 SR 1304 SR 1306 SR 1307 TS 3021 T 242 T 242 T 56 T 56 T 714 T 714 T 704 NA NA NA T 51 T 57 T 57 TS 3002 TS 3002 T 52 TS 3001 T 728 T 709 T 56 T 709 T 801 T 801 T 801 T 80 1 T 728 T 729 T 729 T 734 T 729 T 729 T 729 T 803 T 803 T 803 T 803 T 714 T 714 T 716 T 57 T 735 T 55 T 55 T 723 T 732 T 55
75. 5A Master Chro Bar Generator 189 00 56 00 Down Model WT 333A Picture Tube Tester Rejuvenator with SIMUL TEST 189 00 56 00 Down Model WP 702A Dual Output DC Power Supply 99 00 30 00 Down TRADEMARK s REGISTERED MARCAS REGISTRADA s Specialists demand the best tools of their trade Electronic Instruments Circle 77 on reader service card y 4 Giant Steps Forward 12 04 truly fantastic BRAND NEW W TV Service Instrument More than two years in development Modular microcircuit construction Masterpiece of miniaturization MASTER SUBBER MARK V The GIANT ina tiny package Designed for servicing the ENTIRE signal circuit system of any Color or Black amp White Television receiver by signal substitution Substitutes the following signal stages VHF Tuner Sound detector stage Each video i f stage Audio amplifier stage Video detector stage Provides tests for Video amplifier stage Positive and negative going signals available UHF tuner simultaneously Antenna system 4 5 MHz sound i f amplifier stage AGC system Sound limiter stage Use on the bench or in the home Equipped with wall plug in transformer for 120 vac line instrument automatically changes over to internal battery power when transformer is disconnected Inbuilt monopole antenna allows use without connection of outside ante
76. 7ai6 a6 O S5N7447 145 Fl SNeaes ioe m SNF AiAi TE EOS 120 S J SN7411 3s SN7448 1 50 O SN7486 ss 0 SN74145 155 O SN74181 3 95 l C amp LED HOBBY ONIC og SN7413 95 SN7450 30 L SN7489 350 Ll SN74148 4 59 C SN74182 1 20 F l 1 SN7416 58 0 SN7451 30 C N7490 1 49 5N74150 1 61 O SN74185 2 50 i 709 dip pak op amps untested x Dzin i SN7420 30 O 5N7453 30 Cl N7491 1 35 C N74151 1 25 O SN74192 1 95 ae wee Caz3000 OE PAMES Ts jcasen J Put Your Trust 1 O SN7421 55 O SN7455 55 D SN7492 1 35 O SN74152 492 O SN74193 1 95 ae SE LOCK LOOPS hobby 565 560 561 ao Paks Sk C SN7422 135 O SN7462 35 SN7493 135 O SN74153 1 60 SN74194 1 95 O 3 PHA Case 536 140 565 BAT T4410 CUAWANTE EY lt 1 J N742S5 50 SN7464 30 C SN7494 1 35 5N74154 210 L N74195 1 25 ope TTINEAR AMPS 709 710 711 741 TO 5 i C SN7426 55 O sn7465 50 5 SN7495 1 35 SN74155 1 55 L SN74196 2 50 M10 LIN DIO AMPLIFIERS Westinghouse 10 5 S i O0 SN7430 30 SN7496 1 35 SN74156 1 45 O N74197 2 50 S were RY CELLS SN7481 up to 16 cell DII oer O SN74100 1 65 2 SN74157 1 55 C 5N74198 26 z S AOS REGISTERS 50 to 5017 TO 5 ile ae i DIP Pachages SN74107 70 O SN74158 1 55 SN74200 sae CSM s TIC and CD4000 series DIP pa z s E A a A E E UBT hohhy TOE S1 maau RCUIT SOCKETS OP AMPS 709 i 1 DI Ps TO 5 1 INTEGRATED CI O 10 MINI DIPS 33 536 550 555 i x ALi a a O AGER
77. 8195 FREE catalog IC s PUT s transducers ther mocouples LED S transistors circuit boards parts CHANEY S Box 15431 Lakewood Colo 80215 LOW noise resistors W 5 carbon film from 10 to 3 3M ohms for 3 5c each Fifty of one value for 1 25 Specifications upon request 75c postage and handling charge Deduct 10 on orders over 50 00 COMPONENTS CENTER RE Box 134 New York N Y 10038 DIGITAL clocks close out sale four digit L E D readout wired case 34 75 each ASTRO LABS Box 524 Mesa Arizona PRINTED circuits made hobby prototype P C TECHNOLOGY Box 919 Cupertino Calif 95014 JAPANESE transistors wholesale prices free catalog WEST PACIFIC ELECTRONICS Box 25837 W Los Angeles Calif 90025 FREE C B channel locator map for all hwys of the U S Send 10c to cover postage CLASSIC ENTERPRISE 4069 E Gage Ave Bell Calif 90201 SEMICONDUCTORS components unusual items discount prices Catalog 20c SEABOARD INTERNATIONAL ELECTRONICS Box 906 Clute Tex 77531 BURGLAR fire alarm catalog Wholesale sup lies for home do it yourselfers From the simp est to professional alarm parts and tools Free catalog WHOLESALE SECURITY DEVICES 21415 West 8 Mile Detroit Mich 48219 DIGITAL electronics Complete schematics parts lists theories Discrete component digi tal clock 3 00 Increase technical compe tence hobby skills Complete course in Digital Electronics is hi ni
78. 9 RS276 2009 RS276 2021 RS276 2021 RS276 2009 NA RS276 2011 DM TS 3001 NA T 720 T 55 T 55 T 736 T 736 T 736 T 56 T 709 T 709 T 803 T 803 T 803 T92 T 52 T 52 T 32 T 32 TS 3021 T 240 T 240 T 736 T 3 TS 3021 TS 3021 TS 3021 TS 3021 TS 3021 TS 3021 TS 3021 TS 3021 T 56 T 55 T 709 T 50 T 803 T 230 232 T 232 T 230 232 1232 T 232 T 625 T 232 T 625 TS 3002 TS 3020 TS 3020 TS 3020 TS 3020 TS 3020 TS 3020 TS 3020 TS 3020 TS 3020 TS 3020 TS 3020 T3 3007 T 56 T 716 T 57 T 57 T 736 T 736 T 736 T 716 T 708 T 50 T 736 T 56 SR 1301 SR 1302 SR 1304 SR 1306 SR 1307 NA NOT AVAILABLE G E NA GE 61 GE 20 GE 62 GE 62 GE 20 GE 18 GE 20 NA NA NA NA GE 17 GE 20 GE 20 GE 20 GE FET 1 NA NA NA ICC ICC S0001 ICC 720 ICC 720 ICC 55 ICC 55 ICC 736 ICC 736 ICC 736 NA ICC 709 ICC 709 ICC 803 ICC 803 ICC 803 ICC 52 ICC 52 ICC 52 ICC 52 ICC 52 ICC S3021 NA NA ICC 736 ICC 3 ICC 3021 ICC S3021 ICC S3021 ICC S302 1 ICC S3021 ICC S302 1 ICC S3021 ICC 3021 ICC 56 ICC 55 ICC 55 ICC 50 ICC 803 ICC 230 232 ICC 232 ICC 230 232 ICC 232 ICC 232 ICC 625 ICC 232 ICC 625 ICC 3002 NA NA NA ICC S3002 ICC S 3002 NA NA NA ICC S3007 ICC 56 ICC 716 ICC 57 ICC 57 ICC 736 ICC 736 ICC 736 ICC 716 ICC 708 ICC 50 ICC 736 ICC 56 ICC R1301 ICC R1302 ICC R1304 ICC R1306 ICC R1307
79. ATIONS 26 FOR it 5 LM308 ULTRA HI IMPED OP AMP eee LM208 PRECISION ULTRA HI IMPED OP AMP 22 2 i 33 NES55 TIMER WITH SPECS amp APPLICATIONS 1 10 NES96 DUAL 959 TIMER WITH SPECS amp APPLICATIONS 9998 A QUAL 741 OP AMP NES65 PHASE LOCKED LOOP nnna eee eee 2 95 NES6G FUNCTION GENERATOR 99 NESG7 TONE DECODER jiocce cine tem eaea host mea anc eins 2 95 9314 DIGITAL CLOCK CHIP 2c 2c osc oaan 9 95 ALL IC S BY FIRST CLASS MAIL NO XTRA COST JTM ASSOCIATES P O BOX 843 MANCHESTER MO 63011 Circle 84 on reader service card WIRE GRABBER To avoid the hazard and mess caused by flying component lead trimmings add a wire grabber to your diagonal cutters First thoroughly clean the in side of the jaws with a degreasing sol vent Then fill the hollow of the jaws with silicone rubber sealer GE Dow Corning ete and slip rubber bands over the handle to hold the jaws closed Let the sealer cure over night then slit the seal with a razor blade by running the blade between the cutting edges Curl B Van Wormer Pa g FILL RECESS WITH RUBBER DN SLICE WITH RAZOR BLADE R BBER BANDS REWIND WHILE YOU LISTEN If you make this rewind unit from an old tape recorder you can rewind tapes without tying up vour good tape deck Using only the transport mechanism of GREGORY ELECTRONICS The FM Used Equipment People send lor Naw
80. E aie ai or 2n pin 4 IC S FOR EXPERIMENTERS auy any 3 D14 2 DIP sas O 1 5311 14 e A A CHIP nowy exp 40 pin specs e Money Back Guarantee Factory Marked 1 00 7 Take 10 gt 16 Pin DIP f E at arpa N GENERATORS hobby for MAN 2 1 SN7400 20 tor 1 O SN7490 5 tor 1 i EE Discount jyo s5 8 or 10 Pins Di 2516 GENERATOR Hobby for MAN 2 1 O _SN7403 20 tor 1 SNv4tey7 12 for 1 4 J 14 Pin Wire Wrap 69c m e Se ee many parts from computors a O SN7413 5 for 1 O SN74121 10 for 1 Lage Ol 16 Pin Wire Wrap 89c J BS Ee oe Gace a by Sprague DIP u test em es 1 119 SN7441 S forsi CI SN74123 10 ftor 51 4 j O 16 Pin 1 AM RADIO ON A ee oe n A Chip fallout Sprague ties 442 5 for 1 SN74150 3 ter 1 u postage Rated net 40 E ATT Stereo Amp O 1 O SN7 perms atn post 517 248 3829 O 1 DUAL 2 W like MAN 5 green l or more segs gone 1 C SN7444 5 for 1 C SN74154_ 5 for 1 hone Orders Wakefield Mass 617 ld Ma OP p Or Moure segs i 1 gt vi ine St Wa A r See os SLA 3He A P cherie readout 1 or m te pacts jae 1 D SN744s __ 5 for 1 SN74181 3 for 1 Retail 16 18 Del Carmine S k DE PHONED s SIMONSANTO onte isolators no test 1500V cts no test 1 Ll SN7446 _ for 1 D SN74192 5 for 1 olf Water Street C O D S MAY B ee 5 MO BY SURPRIZE asst types factory reje on l O SN7447 _ 5 tor 1 D SN74193 5 for 1
81. EE 1974 catalog listing all of our outstanding kit projects KDB TRIT eee sera ees 39 95 ppd Southwest Technical Products Corporation Tr DEPT RE 219 W Rhapsody San Antonio Texas 78216 Circle 2 on reader service card HI Fl TEST INSTRUMENTS continued from page 37 A typical audio voltmeter has one or more ranges with full scale readings in the mill ivolt range so you can measure the output hum and noise from such low level sources as microphones tape heads and phonograph cartridges Many audio voltmeters include a built in high gain amplifier that can be used as a preamp for a scope when measuring low level signals The lowest full scale range is to 2 millivolts and the decibel range is from around 80 dB to 60 dB with 0 dB referenced to 0 775 or 1 0 volt A number of FET multimeters have full scale ac voltage ranges low enough to permit making valid measurements of all except the lowest signal voltages found in modern audio equipment So if you are just getting Started in hi fi servicing and have one or more good FET multimeters you inay want to defer purchasing a more specialized audio voltmeter until the volume of business war rents it An audio voltmeter is especially useful in signal tracing where you may need to detect small differences in voltages at correspond ing points in the two channels of a stereo amplifier Audio attenuators Decade attenuators are used between the audio test oscill
82. ER is available from your Chemtronics Distributor Try it You ll love it INCORPORATED 4260 RALPH AVE BROOKLYN NY 44236 Our business is improving yours Circle 9 on reader service card 17 pi et aes bns s A 4 e rrr a e A vals may Aiai r i e i te ok Lf Re i Sy kl i i w vu tea oo m A a aT D seers er This important job land its big income is reserved for a qualified electronics technician It can be you It s a fact There are thousands of jobs like this one available right now for skilled electronics technicians What s more these men are going to be in even greater demand in the years ahead But how about you Where do you fit into the picture Your opportunity will never be greater Sso act now to take advantage of it The first step Learn electronics fundamentals develop a practical understanding of transistors trouble shooting techniques pulse circuitry micro electronics computers and many other exciting new developments in this growth field Prepare yourself now for a job with a 18 bright future unlimited opportunity with lasting security prestige and a steadily growing paycheck Cleveland Institute of Electronics courses have been stepping stones to good jobs in electronics for thousands of ambitious men Why not join them You can learn at home in your spare time and tuition is remarkably low Read the
83. ETTER s 66 Allison Autamotive hY m x SAMPLE COPY 1 00 Bell amp Howell Schools 4 57 LOGIC NEWSLETTER Your en 414 15 BA K Division of Dynascan Corp 26 2 POB 252 70 Brooks Radio amp TV Corp oe RD WALDWICK N J 07463 a gt Association Castle TY Tuner Service Iac m COVER IV 2 Channellock Ine l 79 9 Chemtronics Ine ele 10 CIF Cleveland Institute of Electronics 18 2 PASS FCC EXAMS Memorize study Tests 67 Continental Specialties Corp 7 n r Or n n Radio i i pi a eta ohh caste fen CREI Division of the McGraw Hill noice Queslons and diagrams Cover al areas Continuing Fducation Center B2 NS tested in FCC exams plus Seif Study Ability 6 Crown International 14 Test 995 postpaid Moneyback guarantee s 2 COMMAND PRODUCTIONS P O BOX 26348 E ie S ne RADIO ENGINCERING DIVISIONS SAN FRANCISCO CALIF 94120 A a a Cl lt lt z Digtal Concepts 73 BUILD A SPARE AGE TV CAMERATI D Oep ONLY KNOWN SOLID STATE CAME RA IN KIT FORM x e Also available factory assembled Ideal for Bal Edie Electronics 76 autlinpevarnance wehed by over geven arnt 76 Fdmund Scientific Co n L00 lob aa Field testing Fully aad La J 4 Z EICO Electronic Instrument Co 0 a Soe mnatelans Sire Ae 72 E amp L Instrument Ine 90 A UE Rocked Ceo odet XT t Seles D com EMC Fleetronic Measurement Corp Egil ele w Y 14 anywhere in USA ag st hess eer 4 116 95 pp Many other i 5 ES Enterprises A BO kits parts on
84. Each digit QO 11 character with its own bubble lens Needs as litthe as 1 mw digit for power Requires standard SN74 48 driver combination of LM 74491 and T drivers Fits into l4 pin dip IC socket able 4 digits to right 4 digits te left spate and digits for clocks Buy digits obtain your X digits for lators Very versatile moni readouts X equals fect digit Zero empty digit Common cathode properly multiplexed EST PERFECT PRICE 100 MIDGET DIGITS AT MIDGET PRICES by HP top manufacturer 7400 Series LOWEST You ve seen these you ve seen them but never at our low Made 5062 ane heral digit redout find pel per 3 types and 2 guaranteed Circle 83 on a outper fea not incandescents not nixie but the modern LED Choose from such famous Litronics thar same the ultra modern 9 digit LED array FOR EVERY Properly multi Individual BUBELE LENS for enlarged viewing keyboard and calculator chip per height or 71492 segment and digit avail digits back to back 4 8 or 12 digit caleu per type 1 perfect DIGITS AT THE LOW bomoa reader a MEDIUM LED Mta b Sa y OAK F 210 125 yellow dif For Unique Panel RTTY tvo aa kaii aj or fused lens for indicator Switches same as used in Peli ster 0O 1 0 CEt use 2 4V a 10 mils Calculator SPST Normally O 2 0 cit Upright Open AV 1l amp contacts O 3 D t T Seats Characters and letters O 3 0 4 o
85. F at 1to0 300 mV and by 20 pF at1 to 300 V Amplifier output Is approximately 2 5 Vrms fullscale at 200 ohms Power supply 115 230 V 50 60 Hz 37 ae Me s ee ee or ee oe UNDERSTANI r app F Bean ia j E aa Basically the electron it were not for the great ar it would be priced faf ey OF i feam i gta i z iR r gi 1 mF py i EtA 4 f HE by DON LANCASTER MOST LOWER PRICED CALCULATOR SYSTEMS CONSIST OF very few parts a display and driver assembly a keyboard a bat tery and case a clocking system and decimal point and constant selectors and finally a single integrated circuit that does all the work A block diagram of a typical calculator is in Fig 1 Numbers and program commands entered by the keyboard are carried out and used by the integrated circuit and answers are then routed to the display Since the integrated circuit does everything our overall system complexity changes very little if we add squares square roots per centages metric conversion etc All that happens is that the inner workings of the integrated circuit get slightly more complex and perhaps a key or two is added The way to understand these circuits is to understand what the IC does and how it works Let s take a closer look Some basic operating principles If we had no worries about total calculation time supply power circuit complexity or the number of pins and interconnections on the packa
86. FCC ticket ts your goal this streamlined program will do the trick and enable you to maintain and service all types of transmitting equipment 4 Electronic Communications Mobile Radio Microwave and 2nd Class FCC preparation are just a few of the topics covered in this com pact program Highly recommended for jobs with telephone companies 5 Industrial Electronics amp Automation This exciting program includes many important subjects such as Instru mentation Solid State Devices used in Pulse Digital and power controls 6 Electronics Engineering A college level course for men already working in Electronics covers Steady State and Transient Network Theory Solid State Physics and Circuitry Pulse Techniques Computer Logic and Mathematics _ through Calculus Circle 10 en reader service card An FCC License or your money back The CIE courses described here will prepare you for the FCC License specified In fact we are so certain of their effec tiveness we offer this Money Back Warranty when you complete any CIE licensing course you ll be able to pass your FCC exam or be entitled to a full refund of all tuition paid This warranty is valid during the completion time allowed for your course You get your FCC License or your money back cie s AUTO PROGRAMMED Lessons help you learn faster and easier Cleveland Institute uses the new programmed learning ap proach Our Auto Programmed L
87. GD MoJULY 1974 adio Electro THE MAGAZINE FOR NEW IDEAS IN ELECTRONICS DON LANCASTER TELLS How Calculator BUILD THE MARK 38 IC s Work Your Personal Minicomputer NEW FM CIRCUITS For Precise Tuning DESIGN YOUR OWN Direct Coupled Transistor Amplifiers WHAT YOU NEED In Hi Fi Test Gear WORKING WITH SCR s An PAPeEORIeT Sa Guide a PLUS Appliance slin aak Deiat f Jack a rs Ser ice Gynic step 4 tep FV iro bleshooterts Guide a R E s Ret ple i ent Transistor Directory of Xe writes ME cecrnones INC E f HOME OFFICE INDIANA 5233 S HWY 37 BLOOMINGTON INDIANA 47401 TEL 812 824 9331 ALABAMA 524 32nd ST SOUTH BIRMINGHAM ALA 35222 TEL 205 323 2657 CALIFORNIA NORTH 14611 AUBURN BLVD SACRAMENTO CALIF 95841 Does i z s proud to announce the ISAN DIEGO CALIF 92105 GRAND OPENING of our new Service Centers in BIRMINGHAMSALAY COLORADO 4958 ALLISON ST ARVADA COLD 80001 i 303 423 7080 FLORIDA 1918 BLANDING BLVD JACKSONVILLE FLA 32210 TEL 904 389 9952 INDIANA 15233 S HWY 37 BLOOMINGTON IND 47401 TEL 812 824 9331 KANSAS 3116 MERRIAM LANE KANSAS CITY KANSAS 66100 TEL 913 831 1222 x LOUISIANA 2914 WYTCHWOOD DRIVE METAIRIE LOUISIANA 70033 TEL 504 885 2349 MARYLAND 11105 SPRING ST SILVER SPRING MD 20910 R 301 565 0025 MASSACHUSETTS TALOUISSIMO
88. Ga amp 1 ied pushpull output Power supply require O LM 380 2 watt audio amplifier T iP 1 95 739 739 Dua stereo Pro 5 89 we ih Output to 8 ohms Order by Steck No O LM 381 Low noise sate pre ime DIP 1 95 E ee Watt lye ee 1 00 se dual Pre PA265 5 Watt v A i 00 5 LM 703 RF IF amp 12 5 al 36 ULN2300M 8 amp wih SER cae J LM 709 Operational amplifier A 45 I CA306S Video Audio system p SEMI KON Qr r LM 710 Differential amplifier 36 RC4195 Dual 15V Tracking V 1 95 SEMI KON J amp M 712 Dual Diferantiai a 69 4136 Quad 741 s DIP a N5296 35 WATT NPN PLASTIC TRANSISTORS for oe NEB AO as al eM zI o a tolle 95 AN Ton ne lah Buy any 3 O 2 2 PLASTIC TRANSISTORS capt 5 i M 72 nsir 1 E 2N6109 49 WATT PNP 3L j a 733 Differential Video a 2 igi ines GERMANIUM UHF oo ee al TE 1 T A ai Freq Comp 709 A ae EX KING Money Back 5 SCRs 7 AMP T0220 t ae 0 18 Fairchild 1 O0 amp M 741CV Mini DIP 741C 89 A 10 MOS FETS 3N187 3N200 3N128 T studs too 1 F LM 747 Dual 741 A 44 Susrantee ee SCRS amp TRIACS up to 25 amps 6 atti TU 18 HD F LM 748 Freq adiustabie 741C A 95 2 2N3819 A E E pe ee Texas 1 0 LM 1303 Stereo pre K a l 1 25 Sale 2N2646 UNIJUN Dia ee yen ae lt i 1304 FM Stereo Multlp m 23 re Z M BD o N glass rectifiers computer axial leads 1 J LM 1305 FM mult Stereo Dem DIP a g 300 5 for 1 565 See 1 C SO SILICON
89. LOG on Fiber Optics ICs Semi S Parts J 10 LED HOB i i 33 charac or more segs g N744 P 1 1 15 CATA o O 2 OPCOA SLA 1 MAN A a e ice a missing red O SN7448 S tors O SN74199 3 for 1 O S MONSANTO MAN a 12 charac red 1 or more mera missing M a euo LY PAKS Ges ANAL S some digits Kooti O 2 3 DIGIT E AAR OP ANDE cal 11 series 2120 series 2i a 1 or ahs Laat ont ee tacts who hee Mice D 1 MANS THE CLAW one dot missing 100 hl ee 1 _ P 0 BOX 942R LYNNFIELD MASS 01 hobby Digit Calculator on a Chip hobb 1 D 2 MM5736 6 00 Series ICs dips hobby NATIONAL 9000 Se g 10 FAIRCHILD Circle 83 on reader service card 99 LIVE IN THE WORLD OF TOMORROW TODAY Ainii Ee a ie iia physical science tomes 4 500 finds for fun study or profit for every mem ber of the family unusual ecological amp physical science items plus ee Saal NEW KIRLIAN PHOTOGRAPHY KIT ze CDCA ai n Wi RN Experiment in the fascinating new field of Kirlian electro photography images obtained on film without camera or lens by direct recording of electric charge transmitted by animate amp inan imate objects Each aura differs from another animate aura said to change corresponding to physical changes 50 Kit gives algae needed except film including portable darkroom double me 10 Pere SoS Ug isolated from power source complet
90. LORIDA FAMPA FLORIA 33606 GEORGIA 45 ATORNTA GEORGIA 3p3te i ILLINOIS CHICAGD ILLINOIS 60621 ILLINOIS T vane SKOKIE IWUNOIS 60076 INDIANAN INDIAWAMOTIS IND 46264 INDIANAL HAMMOND INDIANA 46323 TT KENTUCRY LOLISVIECE KENTUCKY 40298 LOUISfANA SHREVEPORT LOUISIAWA74104 MARYLAND BARTIMORE MD 21215 MISSOURI ST DOIG MOi 63132 f NEVADA LAS W amp GAS NEVADA 89102 NEW JERSEY JERSEY city NEW JERSEY 973407 NEW JERSEY TRENTON MEW JERSEY 08638 OHIO py onn tea nba CINCINNATI NQHIO 45216 f OHIO e056 y CREVELAND OMLO 44109 2 f OREGON PORTLABIDP OREGON 97210 WATCH US TENNESSEE GREENVICURSTENNESSEE 3774 S GROW TENNESSEE MEMPHIS TENNESSEE 38111 TEXAS DALLAS TEXAG 75218 VIRGINIA NORFOLK VIRGINIA 23502 j CANADA TUNER SERVICE CORP QUEBEC suum 537 SOUTH Walnut St aaan aa n Tel 812 334 0411 pinia 1528 S 6th St P O Box 4534 niata Ta Tages el602 7919243 wa 1324 Marsten Road 0 00 02 70b 415 347 5728 Eru oe 123 PAGONIX AVe cueie ina ada raaa Tel 209 521 8051 10654 Magnolia Blvd o 0 un diwali lads Ges Tel 213 769 2720 SAFTA 1505 Cypress St 0 ee eee ee ee ee TOR 818 253 0324 938
91. NIC test instrument catalog 160 il lustrated pages list over 5000 new used and reconditioned test instruments 600 manufac turers Send 2 50 refundable with first pur chase TUCKER ELECTRONICS P O B 1050R Garland Texas 75040 GIANT 126 page Canadian surplus catalog 1 00 ETCO ELECTRONICS Dept RE Box 741 Montreal Canada E TELEVISION course 13 lessons complete in cluding four monochrome color servicing manuals 832 pages only 13 95 PUBLICATIONS 1760 Balsam Highland Park IIl 60035 40 PIN SINGLE CHIP 740 Add subtract multiply and divide 74L51 12 Digit display and calculate 74H51 Chain calculations 7453 True credit balance sign output 7454 Automatic overflow indication 74 54 Fixed decimal point at 0 2 3 or 4 7455 u Leading zero suppression 7460 DATA ONLY refundable with 7471 purchase of chip f 7472 COMPLETE WITH DATA 74L72 7473 CD 2 COUNTER KIT 74L73 Unit includes board 7490 7475 quad 7474 latch 7447 seven segment driver and 74H74 RCA DR2010 a Z 2 74178 EUNA TERA 77 7480 7483 COMPLETE KIT only 11 25 FULLY ASSEM 7489 BLED 15 00 boards can be supplied 7490 separately at 2 00 per digit E KEYBOARD ASSEMBLY 333 TRW Data Systems unit 10 keys 0 9 3 7495 or 4 24V lamps printed circuit 74L95 board w 14 1N4001 diodes capacitors 74107 transistor and resistors Ail moun 74121 ted in an attractive case approx 4 x 4 x 2h These are
92. ODED a AS 10 TO DETECT KEYPRESSED EACH KEY b SHORTS Jenin ne WIRES are UNDER IT CALCULATOR IC MACH COMM P 33338 DIGIT DRIVER LINES TO SINK LINES DISPLAY c g FIG 4 KEYBOARDS MUST BE SIMPLE to minimize the number of lines and external parts Matrix c and scanning types d are best face circuitry Newer calculator IC s such as the General Instruments CZL 550 can directly drive some LED display segments and a companion IC is available for digit line driving At the same time LED systems are becoming more efficient and reducing their cur rent needs to levels that are compatible with calculator IC technol ogy Liquid crystal displays with their essentially zero current con sumption and low voltage operation should eventually dominate the calculator display market if and wher practical multiplexing schemes are worked out and a few other production and life prob lems are worked out With today s chips and circuitry you still must use some sort of interface circuitry either in the form of additional IC s or Darling 39 aq y eS Dar pp a e a CES ton connected transistors and resistors The interface circuitry ob viously must meet both the needs of the IC and the display taking into account the data sheet values of each device Scanning keyboards Our keyboard data entry system must use the simplest possible key switches minimum external encoding components a
93. R O N TRANSISTOR FIG 5 A shorted blanker transistor in the same chassis will cause one dark bar on the screen with an otherwise blank raster Same as before it s in the cathode circuit of the 6MN amp color difference amplifier tube Upsets the bias see Fig 5 R E reader questions AFC COLOR PROBLEM The color pops in and out in this Zenith PON IC36 However iff put the afe switch to off the color stays in Pve changed all f the tubes in the color section no help Whats wrong IM Phila Pa Nothing in the color section appar ently This is an intermittent afe prob lem Sounds as if it is detuned just enough to keep the color hanging on the edge and at any disturbance such as noise it lets go Realign the afe and it should stop the trouble TO YOUNG TIMER l have an old amplifier Its an YEr 4712 11 seems to he in good work ing order but don t have a schematic Ht has a pair of 7 pin sockets on the back that I don t understand The ac line ts con nected to pins 6 and 7 Whar s this for and what are the output impedances T d Tons River NJ Unfortunately can t help you with a schematic don t seem to have one for this make It s standard amplifier cir wood cuit though Class A output with 6V6 s The 7 pin sockets on the back are for the speakers The jumper between 6 and 7 is intended to break the primary circuit to the power transformer so that it can t he operat
94. R1 R2 220 ohms R3 560 ohms R4 1800 ohms R5 R6 R7 R8 R17 1000 ohms R9 thru R16 22 000 ohms XTAL 1 4000 000 KHz crystal type EX 3 95 from International Crystal 10 N Lee Street Oklahoma City OK Misc PC Board No 24 wire solder INPUT MULTIPLEXER BOARD C1 C2 C4 0 1 uF disc C2 1 0 uF 10 V electrolytic iC1 IC2 8263 multiplexer Signetics IC3 7400 IC4 IC5 8267 multiplexer Signetics IC6 7402 IC7 7442 decoder P1 P2 P3 P4 Molex type 09 52 3081 con nectors R1 1000 ohms Misc PC board No 24 wire solder ADDRESS LATCH BOARD C1 thru C6 0 01 pF disc ceramic C7 680 pF disc IC1 1C2 74123 dual monostable IC3 164 105 106 IC7 7400 IC8 IC9 IC10 IC11 74193 programmable counter P1 P2 P3 Molex Type 09 52 3081 connectors R1 thru R3 10 000 ohms 32 PARTS LIST R4 22 000 ohms R5 thru R16 1000 ohms Misc PC board 324 wire solder MEMORY BOARD C1 C2 C3 0 1 uF disc ceramic IC1 thru IC8 1101 1101A or 1101A1 memory circuits 256 x 1 IC9 thru C32 Same as above but optional with butlder IC33 7442 decoder IC34 7 400 P1 P2 Molex type 09 52 3081 connector Ri thru R11 R20 R21 1000 ohms R12 thru R19 10 000 ohms Misc RC board No 24 wire Solder OUTPUT LATCH BOARD C1 C2 C3 0 1 pF disc IC1 thru C8 7475 quad latch IC9 1C10 7404 IC11 7402 IC12 7442 P1 P2 P3 P4 Molex type 09 52 3081
95. RCUIT DESIGN A key skill which paces our nation s progress in count less fields from pollution control to satellite tracking to modern medicine to exploring the ocean s depths And beyond A skill which you must have to move to the top in advanced electronics CREI programs open up new worlds of opportunity for you In addition to electronic circuit design CRE provides you with a full advanced electronics education in any of thirteen fields of specialization you choose Communica tions computers space operations television nuclear power industrial electronics to mention just a few of the career fields for which CREI training is qualifying With such preparation you will have the background for a career which can take you to the frontiers of the nation s most exciting new developments And around the world a ee eee EE CREI Dept E 1407 E 3939 Wisconsin Avenue Washington D C 20016 graduate Name Address __ Employed by Type of Present Work Rush me your FREE book describing my opportu nities in advanced electronics am a high school City State If you have previous training in electronics check here O This free book can change your life Send for it If you are a high school graduate or equivalent and have previous training or experience in electronics then you are qualified to enroll in a CREI program to move you ahead in advanced electronics Send now for our ful
96. RED BY SPR THIS MESSAGE WAS PREPS Gi ioe CO eegrreTeae Pr we NT TV RAD YOUR INDEPE PUT THIS BUSINESS BUILDING TRAFFIC STOPPER ON YOUR SHOP WALL OR IN YOUR WINDOW See your Sprague Distributor for window size blow ups of this message Or send 25 to Sprague Products Co 81 Marshall St North Adams Mass 01247 to cover handling and mailing costs Just es 4112 ask for Poster RP 42 SPRAGUE THE MARK OF RELIABILITY THE BROAD LINE PRODUCER OF ELECTRONIC PARTS Circle 13 on reader service card 27 28 while the guy down the street complains about how tough alignments are 1 do them oe a a x z j we f a used to hook up a separate sweep generator marker generator marker adder and bias supply hope that everything was properly calibrated and adjusted and pray that the alignment would hold after discon nected the cables draped all over the bench didn t do it very often Now in the time it used to take me just to set up can almost complete an alignment And I m confident the set will perform as well as it possibly can My cus tomers notice too That s the difference B amp K s 415 Solid State Sweep Marker Generator made setud is no problem After connect the 415 s out puts tc my scope there s even low frequency com pensation to eliminate pattern errors connect its RF outputs channel 4 or 10 to the antenna terminals or mixer test point the direct probe
97. Radio Electronics for its use We have used the latest manufacturers material available to us and have asked each manufacturer covered in the listing to check its accuracy Where we have been supplied with corrections we have updated the listing to in clude them The first part of this Guide appeared in March 1973 2N3554 2N3563 2N3564 2N3565 2N3566 2N3567 2N3568 2N3569 2N3570 2N3571 2N3572 2N3573 2N3574 2N3575 2N3576 2N3579 2N3580 2N3581 2N3582 2N3583 2N3584 2N3585 2N3587 2N3588 2N3589 2N3590 2N3591 2N3592 2N3593 2N3594 2N3595 2N3596 2N3600 2N3605 2N3606 2N3607 2N3608 2N3611 2N3612 2N3613 2N3614 2N3615 2N3616 2N3617 2N3618 2N3619 2N3620 2N3621 2N3622 2N3623 2N3624 2N3625 2N3626 2N3627 2N3628 2N3629 2N3630 2N3632 2N3633 2N3638 2N3639 2N3640 2N3641 2N3642 2N3643 2N3644 2N3645 2N3646 2N3647 2N3648 2N3649 2N3650 2N365 1 2N3652 2N3653 ARCH NA RS276 2015 RS276 2015 RS276 2009 RS276 2009 RS276 2009 RS276 2009 RS276 2009 NA NA NA NA NA NA RS276 2023 RS276 2023 RS276 2023 RS276 2023 RS276 2023 NA RS276 2003 NA NA NA NA NA NA NA NA RS276 201 1 RS276 2009 RS276 2009 RS276 2009 NA RS276 2006 RS276 2006 RS276 2006 RS276 2006 RS276 2006 RS276 2006 RS276 2006 RS276 2006 NA NA NA NA NA NA NA NA NA NA NA NA NA RS276 2011 RS276 2021 RS276 2024 RS276 2024 RS276 2009 RS276 200
98. S 500 has been designed on the EICO Expandability Concept that enables you to add on protec tion to meet your own special needs Before you purchase any security system we suggest you read the EICO Security Handbook and see how easy EICO makes it to Do it Yourself FREE EICO CATALOG SPECIAL OFFER Security handbook Reg 2 95 only 1 50 with this ad Includes a catalog on EICO Security Systems Test Instruments Stereo Hobby Kits and name of nearest distributor For catalog only check reader service card or send 50c for first class mail service EICO 283 Malta Street Brooklyn N Y 11207 F NEW FREE CATALOG OF CIRCUIT DESIGN amp BREADBOARDING EQUIPMENT NOW TEST NEW CIRCUIT IDEAS 1 C S DISCRETE COMPONENTS WITH NO SOLDERING Circuit Design s new catalog has every thing you need to take you from circuit concept to working hardware in minutes Featured items include the great SK 10 socket for solderless circuit design and testing the NEW SK 20 socket only 2 75 for smaller circuits the versatile Digi Designer in kit form or assembled a new Op Amp Designer plus power Supplies pulse generators digital logic courses plug in socket boards and much more Write today for your free copy CIRCUIT DESIGNS INC P O Box 24 Shelton Conn 06484 Exclusive mail order dist for E amp L Instruments 90 Circle 72 on reader service card next mont
99. SCRAMBLER II EQUIPMENT At left is the mode selector normally mounted on the dashboard behind it the code processor with the lid raised to show its 18 code setting switches At right is a Scrambler base station the Factory Because they re missing something Like an ignition system built for today s driving Factory electronic ignitions were Okay for yesterday All they do is eliminate the points and condenser you know But today with fuel shortages the ever growing cost of maintenance power robbing smog control devices etc there s a crying need for something better That something better is a Delta Capacitive Discharge Ignition System the low cost now system that really makes sense Means up to 20 better gas mileage 75 fewer tune ups Three to 10 times longer plug life Instant starts even at 40 Better ac celeration and performance Easy to installon any automobile engine too even goes on in minutes right over the factory electronic system with no rewiring Delta Capacitive Discharge a Ignition Systems extra en ergy to beat the energy short age Available in two models Mark Ten CDI or Mark Ten B Priced as low as 29 95 in kit form Use coupon to order today tae ARI yg Bet aer IMARK T Taer Shoul P O Box 1147 Dept RE Grand Junction Colo 81501 303 242 9000 C Please send me free literature Enclosed is ____ O Ship
100. SION SYSTEMS Winegard Company 3000 Kirkwood Street e Burlington lowa 52601 0 0 0 0 0 0 0 0 0 0 0 0 0 0 6 0 0 0 6 6 6 6 6 0 0 Circle 73 on reader service card Accuracy like a VTVM Convenience like a VOM NEW BATTERY OPERATED FET SOLID STATE VOLT OHMMETER 116 Easy to build KIT 32 40 16K Factory Wired amp Tested 44 90_s ew Now you can get all the benefits of a VTVM laboratory accuracy stability and wide range but with its drawbacks gone no plugging into an AC outlet no waiting for warm up no bulkiness New Field Effect Transistor FET design makes possible low loading instant on battery operation and small size Excellent for both bench and field work Compare these valuable features e High impedance low loading 11 meg ohms input o7z DC 1 megohm on AC e 500 times more sensitive than a standard 20 000 ohms per volt VOM e Wide range versatility 4 P P AC voltage ranges 0 3 3 33 330 1200V 4 RMS AC voltage ranges 0 1 2 12 120 1200V 4 DC voltage ranges 1 Name 0 1 2 12 120 1200V 4 Resistance ranges 0 1K 0 100K 0 10 meg 0 1000 meg Address 40B ranges 24 to 56DB Sensitive easy to read 42 200 micro 1 it Y amp meter Zero center position avail State Zip able Comprises FET transistor 4 silicon transistors 2 diodes Met r and tran sistors protected against burnout Etched panel for durability High impact bake lite case with handle
101. T 55 T 55 T 714 T 247 T 704 T 247 T 704 T242 T 242 T 54 T 714 1 714 T 714 T 714 T 716 T 716 T 729 T 729 T 234 T 235 TS 5005 G E NA NA NA NA NA GE 32 GE 29 NA GE 11 GE 11 NA NA NA NA NA NA GE 21 GE 21 GE 21 GE 66 NA GE 21 NA NA GE 11 GE 20 NA GE FET 1 GE FET 1 GE FET 1 GE FET 1 GE 60 GE 60 GE 60 GE 60 GE 20 GE 61 GE 63 NA NA NA NA GE 25 GE 25 GE 25 ICC ICC R1301 ICC R1302 ICC R1304 ICC R1306 ICC R1307 ICC 2021 ICC 242 ICC 242 ICC 56 ICC 56 ICC 714 ICC 714 ICC 704 NA NA NA ICC 51 ICC 57 ICC 57 ICC 3002 ICC 53002 ICC 52 ICC 53001 ICC 728 ICC 709 iICC 56 ItCC 709 NA NA NA NA ICC 728 ICC 729 ICC 729 iICC 734 ICC 729 ICC 729 ICC 729 ICC 803 ICC 803 ICC 803 ICC 803 ICC 714 ICC 714 ICC 716 ICC 57 ICC 735 ICC 55 ICC 55 ICC 723 ICC 732 ICC 55 ICC 55 ICC 55 ICC 714 ICC 247 ICC 704 ICC 247 ICC 704 ICC 242 ICC 242 ICC 54 ICC 714 ICC 714 ICC 714 ICC 714 ICC 716 ICC 716 ICC 729 ICC 729 ICC 234 ICC 235 ICC S5005 IR NA NA NA IR 1844A IR 1846A IR 1849A TR 20 TR 20 TR 20 NA NA TR 30 NA IRTR 51 IRTR 80 NA NA NA TR 21 IRTR 87 NA NA NA NA IRTR 88 IRTR 88 TR 33 NA NA NA NA NA NA NA NA TR 27 TR 27 TR 27 MAL NA NA NA NA NA NA PTC 111 PTC 111 PTC 126 PTC 126 PTC 144 PTC 110 PTC 140 NA NA NA PTC 10
102. T 6 Schober Organ RI 2 Southwest Technical Products rey We supply the following parts to make a dual D C power 13 Sprague Products Corp l o supply with the following ratings O to 42 volts D C at a a Peet GeO 5 0 Amps and 12 volts D C at 5 0 Amps Switch tine fame Stuy Oricon 6467 cord pilot light transformer Variable Autotransformer 2 bridge rectifiers 2 high capacity electrolitic capacitors i p NS Tektronia Ine cas a Meters and cabinet not supplied a tees Cw waren m or she A STOCK NO J5166 Parts Kit 22 50 2 39 00 aU TRR cij aiji RR 3 luner Service Corp nea TUNG SOL DIGIVAC FLUORESCENT A CODE E READOUT TUBE fay Vintage Radio RR Tung Sol DT1704B 7 segment fluorescent 9 pin miniature Wahl Clipper Corp 7 5 readout tube Character size 360x570 Height 1 Fil 11 12 Weller Xeehte Electronics Division eee volts 1 6 AC or DC Segment voltage 12 to 50 volts 25 Winegard Co I s 91 volts typical Electrically identical to G E Y4075 amp Y o Readout colr is green but can be filtered to any O n MARKET CENTER color We supply a socket for each tube and man ages of application data WBa ATV Research Corp l 98 79 Babylon Electronics s ae 93 STOCK NO F5140 2 65 ea 2 5 00 6 14 00 Barta nc l 98 a Command Productions YR Cornell Electronics l 9R include sufficient postage Excess refundedSend for new catalog No so Deltu Electronics 38 1
103. VERSAL TV ANTENNA Back of s 2 79 Mountings 5 ose tion roda COLOR CONVERGENCE ASSEMBLY lni 2 49 versal type good for most sets COLOR TV RECTIFIER Used in most 1 95 color setas 6500 ky 3 for 2 COLOA TY CRT SOCKETS Wired lemis 1 for all color TV s 3 RCA 110 CRT SOCKETS Wired leads 1 for all TV s 70 COLOA TUBE 3 95 BRIGHTNER 90 COLOR TUBE A 95 BRIGHTNER 2 gt COLORBURST QUARTZ CRYSTAL 1 89 For Mixt Color TY seta 3579 HA KC 5 ASSTD GLOBAR VARISISTOR Popular ris g placements for most COLOR TV cannot slip banana Insulated bare wire or ASTATIC PICKUP MODEL 700 897 Con tains 89T ceramic eartridge LIST 8 95 ri 17 00 15 DIPPED MYLAR CAPACITORS 1 O N ce 15 DIPPED MYLAR CAPACITORS 1 33 60O N 15 DIPPED MYLAR CAPACITORS 1 KII LOOO N 19 PE MYLAR CAPACITORS 1 DES F AUN He MOLDED TUBULAR CAPACITORS 15 DIPPED MYLER CONDENSERS 1 0039 400 TUBE SPECIAL ADWa4 12DQ6 2B 17737 SES 75 ea TACHOMETER 2 SQUARE PAWEL METER 1 ViIXC fuil scale 33 Ohm col reawtance 0 6000 R PM t CASSETTE TYPE DYNAMIC MI CROPHONE with universal plugs 200 295 Ohms t0 SETS PHONO PLUGS amp PIN JACKS RCA type B8 PRINTED CIRCUIT IF TRANSFORMERS 4 Lug 456 KC STEREO TONE ARMS Most popuiar type turn over cartridge 4 50 HANKS HOOK UP WIRE assorted 1 colors 100 SPOOL SPEAKER WIRE 2 cond 2 mini zip Clear 101 uses 10
104. Y MODEL 80 176EH ee ios 26 50 Ppd eres nr ee ELECTRONIC SLIDE RULE 89 95 i ip Price breakthrough Texas Instrument cal Cculator easily does classic slide rule wk w split sec accuracy 8 digit s 2 digit ex onents rinus Signs overflows show in red Besides 4 std functions does sq roots Squares reciprocals auto conversion to sci entific notation mixed calc Max amp min s Great fortchrs students on the go 9 02 Incls long life Ni Cad apecneree tle batts amp AC converter charge A No 78 O11 H 6 1 4x3x1 1 4 89 95 Ppd B No 78 014EH ENGR s DESK MOD 139 95 Ppd Description MERCHANDISE TOTAL ADD HANDLING CHARGE 1 00 ON ORDERS l nae UNDER 5 00 50 ON ORDERS OVER 5 00 300 Edscorp Building Barrington N J 08007 a ai ne ke TOTAL Please rush Free Giant Catalog EH p an DAY we enclose 1 check i f MONEY BACK X O money order for Names E ES a a a a i S GUARANTEE u l address a Sa gt YOU MUST BE SATISFIED f x aap i SA OR RETURN ANY PUR F l OA CHASE IN 26 DAYS EA ADDRESS City DAS EREET RNN SSN EN I FUU REFUNG i an Wi ARE rf CITY STATE _ 2 P State A oe aad Seay eee ey 1 ee os L De ee pe mE eee a a a er LDC A E eC M ae LDC QSL A E A 100 Circle 76 on reader service card RCA introduces the easy way to buy test equipment RCA s new Easy Payment Plan makes it possible for y
105. a Calif 95051 ask for a copy of 8008 8 Bit Parallel Central Processor Unit Users Manual This 053 manual was offered free at the time this article went to press 006 177 106 040 000 000 123 026 004 031 110 043 000 021 110 043 000 007 SOFTWARE EXAMPLE OUTPUT LOOP LDAI 177 JSUN OUTPUT short timing loos so that it can not go faster than data may be entered to the TV Typewriter memory Load A with data Data 177 ASCII Jump to OUTPUT subroutine HALT Stop end of program OUT1 Data from A to output port 1 LDCI Load C Immediate 004 Data DECD Decrement D JPFZ LOOP Jump ona false zero flag to LOOP DECC Decrement C JPFZ LOOP Jump on a false zero flag to LOOP RTUN Unconditional return to main program 33 Selecting and Using by ROBERT F SCOTT TECHNICAL EDITOR WHEN MANY OF US BROKE INTO RADIO SER vicing there was no such thing as hi fi Radios were relatively simple AM receiv ers The audio amplifiers were the simplest circuits needed to drive a loudspeaker Later a phonograph pickup was added for record playing Now with FM and FM stereo touch tuning digital readouts and audio circuits flat from below 20 Hz to well beyond 20 kHz the listener s demands for good reproduction and performance have become more severe There was a time when a radio and its audio system could be serviced using a vom with output meter feature a simple rf af signal tra
106. adio Servicing Program you will actually build and keep an all solid state black and white TV set and a color TV set You also construct an oscilloscope which is yours to keep and use on the job FCC LICENSE TRAINING MONEY BACK AGREEMENT Take Sylvania s Communications Career Program or enter with ad vanced standing and prepare im mediately for your 1st 2nd or 3rd class FCC Radio Telephone License examinations Our money back agreement assures you of yourmoney Pe ana back if you take and fail to pass the FCC examination taken within 6 months after completing the course CONVENIENT PAYMENT PLANS You get a selection of tuition plans And there are never any interest or finance Charges SEND ATTACHED POSTAGE PAID CARD TODAY FREE DESCRIPTIVE BOOK YOURS WITHOUT OBLIGATION Sylvania Technical Systems Inc If reply card is detached Send this coupon SYLWANIA TECHNICAL SCHOOL 1 Home Study 909 Third Avenue New York N Y 10022 Please send meFREE illustrated career catalog lunderstandthatlamunderno obligation Name Address City State Zip Age __ Veterans Check here O 758 407 0 S Lae 3 E eee E g gt 7 In the Master TV Radio Servicing Program lt x you build and keep the all solid state black and white TV set the color TV set the os x gillascope and the multimeter shown above 67 ee 2N3654 2N3655 2N3656 2N3657 2N36
107. al amplifier with a fixed voltage across a dividing network When the vol tages are equal the transistor ignition sys tem is turned off then turned on again when engine speed drops below the limit and the voltage from the revolution counter drops accordingly This causes a slight vibration that warns the driver to shift Foragivenengine the system was Set to cut the ignition out at 6600 and to cut it in again at 6500 rpm By keeping the differ ence between the cut out and cut in points down to 100 rpm the resulting en gine vibration is small but nevertheless discernible Earlier mechanical limiters have not functioned precisely enough in certain extreme operational conditions to pre vent engine damage through late cut out or loss of performance because of cutting out before the engine reached ideal top speed The electronic nature of the new rev limiter makes it possible to maintain the 100 rpm separation of switch out and switch in precisely continued on page 12 V ALE k 4 100k 12 2k 8 330 s R4 p 8n Cl eens i t 9s 16 The TELEQUIPMENT D61 is alow priced 10 MHz dual trace oscilloscope with sweep No other 10 MHz oscilloscope gives you all this for 475 and hobbyists Operating Ease Front panel controls are engineered for instant recognition Line or m a i 2 mi E
108. anada BUSINESS OPPORTUNITIES NEW Complete Hong Kong Manufacturer supplier drop shippers lists 20 appd COMMERCIAL COMMUNICATION CENTRE G P O Box 13724 Hong Kong START small highly profitable electronic pro duction in your basement Investment knowl edge unnecessary Postcard brings facts BARTA AG Box 248 Walnut Creek Calif 94597 PROFIT from new emerging electronics Do zens of opportunities in mail order retail ex port service 28 pages of what s happening and how to benefit Send 3 00 CARLTON Box 1743 Ann Arbor Mich 48106 TUBES RECEIVING amp industrial tubes transistors All brands biggest discounts Technicians hob byists experimenters request free giant catalog and save ZALYTRON 469 Jericho Turnpike Mineola N Y 11501 WANTED QUICK cash for electronic equipment com ponents unused tubes Send list now BARRY 512 Broadway New York N Y 10012 212 WAlker 5 7000 WANTED Electro Voice 15TRX speaker BARB McGAHA 4 Craig Drive Springfield Ill 62704 FOR SALE NE555V 1 10 8038 waveform generator 6 95 Intel 1103 4 50 2N6084 10 50 Catalog 10c ELECTRONIC DISCOUNT SALES 138 N 81st 5t Mesa Ariz 85207 TWENTY disc or 10 bar magnets 1 00 MAGNETS Box 192 E Randallstown Md 21133 FREE catalog lists resistors tubes transistors rectifiers condensers tools tuners etc etc HYTRON HUDSON Dept RE 2818 Kennedy Blvd Union City N J 07087 ELECTRO
109. announced price Although home movies buffs presuma bly are welcome as purchas ers Kodak initially is aiming the videoplayer at profes sional users such as schools broadcasters and cable TV systems e Solid state TV ie fl a a a n The days of hybrid color TV seem to be numbered thanks to the energy crisis and the FCC RCA moved up its schedule for changeover to all solid state color sets by a full year and will stop produc ing hybrids at the end of June accompanied by a drumbeat looking ahea of publicity It appears that other manufacturers won t be far behind RCA hybrids are still on the market of course but they were made before the cut off date And they re not identified as 1975 models Several other manufactur ers have quietly stopped pro ducing tube type color sets too But they ve produced enough to last well into the 1975 model year so they re just not saying much about it and labeling their recently produced hybrids as 1975 models That s perfectly fair of course since the hybrids have gone through the cus tomary face lifting required to indentify them as new models You can expect solid state advertising for the rest of the year to feature energy savings claims They re perfectly true of course a_ solid state 25 inch color set uses less power than a _ tube type black and white There s another convincer which de cided some manufacturers to switch to solid state That s the FCC ru
110. as a Dolby encoded tape with ANRS decoding Figures 3 and 4 illus trate just what can happen The sweep tre quency is 20 to 20 kHz recorded 30 and 40 dB below the reterence or 0 VU recording level the primary working range of noise continued on page 26 PROFESSIONAL SCREWDRIVERS x Xcelite LARGEST RANGE GREATEST VARIETY What are you driving Slotted Phillips Frearson Reed amp Prince Allen hex clutch head Scrujox Bristol Spline or Pozidriv screws Xcelile makes screwdrivers for every type and size Metrics too e from 2 1 8 miniatures to huge 2 footers e 040 to 7 16 tip widths e round or square blades e tough forged alloy steel e nickel chrome black oxide finish or insulation coated e fixed handle or interchangeable blades e straight and tee handles regular and ratcheting e available individually or in handy kits Made in U S A to highest standards Ask yiii local distributor or write Weller Xcelite Electronics Division The Cooper Group ORCHARD PARK N Y 14127 PER INDUSTRIES Circle 12 on reader service card 23 24 The editors choice Heathkit Digital Design Color TV _ i t At ELEMENTARY ELECTRONICS they said The fact is today s Heathkit GR 2000 is the color TV the rest of the industry will be mak there is no other TV available at any ing tomorrow price which inco
111. ate Size of display in holder O 5 MV5SS micie mini axial lends red lens red lite 1 00 pa Vie x Vet Operating al 32 hertz O 5 MV5012 red small dome lens red lite TO 18 1 00 See Wie of power Operates from 5V hearing 5 MV5013 sm dome 2 hi red dome soft red diff lite TO 18 1 00 ez we cell Uses the new and latest C MOS Urals circuitry 1 5 MV5020 jumbo clear dome visible red TO 1 w 100 include copy of write up from PE magazine a AP O 1 MV5040 1 LED red array with lead pak re A EAS il im Ee veces a jumbo dome lens TO 18 red lite upright 1 00 j az Dl oe gii mess r 1 amp micro mini red dome red lite gt 1 00 a O 5 MY5080 TO 18 micro mini flat clear lens red lite 1 00 CANG ii NAtOr Seam i POLY PAKS 1 MV5094 red bi polar solid state lamp V to 110 115V AC DC 1 98 a 5 ae j o 2 MV5222 green jumbo dome green lite panel snap in 1 00 R 1 Y i BLUE RIBBON O 2 MV5282 mi cro mini green lens TO 18 green lite 1 00 AIS S o 2 MV5322 yellow jumbo dome yellow lite panel snap in 1 00 5 4 Q 1 MvV5491 jumbo Tri State RED GREEN OFF special 1 49 MAKE YOUR OWN A O 2 MT2 photo transistor light sensor TO 18 s 1 00 CALCULATORS Oo cy COUPLERS Li 2 MCT2 LAOOV isolation photo Toa 1 00 WITH OUR 19 95 2 MCD2 1500V isolation ation nh sto diode 1 00 LOW PRICED INCLUDES 7 AN LED TYPES GIANT SALE ON 3 DIGIT READOUTS 9 DIGITS Made by
112. ator and the amplifier to provide the precise low level signals needed when testing preamps and other high gain audio circuits Some attenuators like G en eral Radio s Microvolter include a preci sion audio voltmeter for setting the input to a predetermined level and two or more step attenuators with dials calibrated in volts and in decibels Typical decade attenuators used for gain and loss measurements of filters amplifiers active and passive networks and similar equipment are General Radio s model 1450 and the Hewlett Packard 4437A These provide attenuation of 0 to 110 dB and 0 to 119 9 dB respectively in 0 1 dB steps When measuring the frequency response of an amplifier an attenuator is needed be tween the audio generator and the amplifier to provide the minute precise adjustments in the input signal level during the frequency run With a constant signal voltage being fed into the attenuator the attenuator is ad PREAMP BANDPASS amp FILTER LIMITER 2 8 3 2 kHz HARMONIC SUPPRESSOR plifier gain varies 0 1 dB This amounts to a voltage ratio equivalent to a gain of 1 012 or a loss of 0 9886 This is a variation of about 1 5 very difficult to read accurately on an analog meter scale Wow and flutter meter If most of your experience has been in radio and TV servicing the terms wow and flutter may be all but meaningless to you but you d better know what it s all about if a musician or other critica
113. be too Most of this trouble will be caused by drift in the matched pair of resistors in the reg ulator grid Leakage in the small capacitor connected from grid to cathode of the reg ulator will also do it If this capacitor shorts you ll have zero grid bias and the regulator 61 LOW 10 kV ETC CATHODE CURRENT HORIZ OUTPUT LOW WEAK TUBE DC VOLTAGE LOW HV RETURNS TOO HIGH HV NOW OK BAD REG TUBE CATHODE CURRENT HORIZ OUTPUT TUBE HIGH HV OVERLOADED DISABLE HV REG HIGH VOLTAGE HV STILL HIGH CHECK DC BIAS HV REG CUT OFF NO CHANGE HV REG POSSIBLY OK FAULT IN OTHER LOAD CIRCUITS BOOST FOCUS ETC SHORTED HV RECT TROUBLESHOOTING CHART helps you find and eliminate defects in high voltage regulator cir cults fast and efficiently will conduct very heavily The 6BK4 plate will probably get red hot This has been known to blow horizontal output tubes and even burn up flybacks The pulse regulator tubes can be checked in much the same way In cases where the high voltage is far too high and the Hv AD JUST control won t bring it down even if it does make it vary check the dc voltages on grid and cathode In one typical set the grid voltage was found to be 200 volts Since the cathode had 390 volts the regulator grid had a 190 volt bias This is enough to make the tube cut off completely Normal grid voltage is 345 volts giving a 45 volt bias The r
114. called the least significant or 1 O part of the address Both the HI and LO address latches are made up of SN74193 programmable coun COMPUTER WITH ASCII KEYBOARD makes a complete working computer system You can use the computer without the keyboard but it is more difficult THE WORKING HEART of the computer is relatively simple The six primary circuit boards and the front panel controls are shown here If additional memory is needed more circuits boards are required ters since the address held in them may be incremented by counting up by one The usefulness of this will be seen later The HI and LO latches are also used for temporary data storage when they are not being used to store a memory address The manual control portion of this module allows us to program the computer and to control its operation from an operator s console We are able to externally address any memory location and deposit data or in structions in it We may also return to any location and check the data stored there Controls are also provided to allow us to single step the computer through a program One instruction at a time and to interrupt the computer while it is executing a program These controls will be described in detail later The Data Input Multiplexer module con trols the flow of all data into the computer All data going into the computer is placed on the 1 O bus during the IN cycle signalled by the IN signal Since data ma
115. cas sette player for autos features fast forward ad justable shafts for easy in dash installation FM ocr ra Q Pi bas ca ie local distant control AM FM selector with indi cator lights and slide rule dial scale New cas sette loading mechanism allows easy cartridge insertion even while driving Pushbutton casset tee ejector facilitates removal 2 12 x 7 x 6 Yein 179 95 Audiovox Corp 150 Marcus Blvd Hauppauge N Y 11787 Circle 32 on reader service card DIGITAL MULTIMETER mode 45 10 000 count digit DMM operates from either line or battery power and is applicable for tuning precision power supply and amplifier circuitry Has five ac and five dc voltage ranges with 10 uV resolution six resistance ranges with 10 milliohm resolu tion andfive ac and five dc current ranges with 10 nA resolution Battery charge life 10 12 hours power consumption 3 watts display 33 7 segment Sperry s Entire unit can be field stripped in less than five seconds Spare fuse and circuit card con nector for testing are housed behind a rear entry panel 2 5x6 25xQ9in 2 3 Ibs without batteries 399 00 Data Technology Corp 2700 South Fairview Street Santa Ana Calif 92704 Circle 33 on reader service card BASE STATION MICROPHONE model BIM4 features dynamic element with cardioid re sponse pattern to minimize background noise and an acoustical damper to preserve full voice quality Also included is
116. ce card The more specialized your field the more you ll need these books cuited logic electronics This practical book helps him over that hurdle It opens with a necessary explanation of the binary number system and Boolean algebra and progresses logically to the practical problems and limitations involved in preparing to work in this new field A glossary of digital terms is included 160 pages softbound No 21081 4 50 HOW TO DESIGN AND USE MULTIVIBRATORS by Courtney Hall This book examines the various types of multivibrators at the introductory level It explains how multivibrator circuits work in switching rapidly from one state to another how they can be designed using a minimum number of components and how they can be applied in practical circuits Many specific projects for multivibrator cir cuits are covered 96 pages softbound No 21043 3 95 PHOTOFACT TELEVISION COURSE 4th Edition by The Howard W Sams Editorial Staff This book has provided the basic knowledge for thousands who have become skilled in the field of tele vision engineering and service Newly updated it presents a complete course in black and white television de scribes the functions of important cir cuits and is supported by numerous schematics Each chapter is followed by questions with answers at the back of the book 208 pages soft bound No 20981 6 95 MODERN RECORDING TECHNIQUES by Robert E Runstein In ex
117. ceiver for use as a temporary replacement when the original tuner is removed and taken away for service This is understandable the Subber is an ingenious idea for signal circuit servicing and the receiver perfor mance is frequently better with the Sub ber than with the original tuner this con veniently leads to the well intentioned temptation to give the customer uninter rupted service from the receiver by loan ing the Subber to him This is a questionable practice and could prove to be a very expensive mis take A little investigation will reveal that any major changes in the operating controls or construction of the TV receiver from the design which received U L approval may well modify such approval It follows that some of the product hazard liability which the manufacturer sought to di minish by U L approval may then be transferred to the technician or service The FM 2400CH provides an accurate frequency standard for testing and adjustment of mobile transmitters and receivers at pre determined frequencies The FM 2400CH with its extended range covers 25 to 1000 MHz The frequencies can be those of the radio frequency channels of operation and or the intermediate fre quencies of the receiver between 5 MHz and 40 MHz Frequency Stability 0005 from 50 o 104 F Frequency stability with built in thermometer and temperature corrected charts 00025 from 25
118. cer and an rf signal generator with built in 400 Hz we called it 400 cycles modulation Now to restore a modern FM stereo receiver to its original performance specs we may need a multiplex generat or analyzer a lab grade audio signal generator with sine square wave and sweep output distortion analyzers dual channel wide band scope with triggered sweep wow and flutter meter audio vivm audio watt meter and a precision decade attenuator A piece of hi fi gear that is inoperative or has one channel weak or completely out ts generally easy to service by using an elec tronic multimeter for voltage and resistance measurements to localize the trouble But when it comes to satisfying complaints from musicians and other critical listeners you may need the whole bag of tricks along with some of the most sophisticated test equipment available for hi fi servicing The specialized gear you ll be likely to need should either be designed especially for hi fi servicing or have known response and distortion characteristics that are equal or better than the equipment you ll be ser vicing Now let s take a look at what fea tures we want in various test instruments and how we can best use them The audio oscillator The basic use of the audio oscillator is as a signal source when trouble shooting audio circuits either by signal tracing or signal substitution For this we are mainly in terested in the presence or absence of the test s
119. comes on with the colors oversaturated and well out of phase Raster s clears no impurity This is a Zenith 1449C50 1 ran an AEPC adjust ment and replaced the IC demodulator chip and the oscillator tube No help Pin lost G C Rockford Tl Polishing the crystal val I would say that this sounds like a 3 58 M H7 crystal which won t quite come to the right frequency Try this hook a 50K resistor in series with the probe of the vivm and read the de voltage on the grid of the 3 58 MHz oscillator tube Use a color bar signal on the set and set up for AFPC alignment Normally the grid voltage should be zero It should be able to go from a S volts to a 5 volts as you adjust the oscillator frequency If the crystal is off it will probably come up to about 0 5 volt or 0 5 volt and then snap out Final test is to try anew crystal of the right part number R E 1 BO 505 ar DUAL ae tae nok wild aed state accuracy For prod ay 6 field maintenance quality ee control labs design amp beating i Features toes oe 15MH bandwidth e Trig kauta sweep aide from 10 manoseccm t IEK mag to Tirte Me Steet re 17 staps calibi d od AC DC coupling per chan e Separate or simultaneous sweep display of ch 1 amp 2 dtermating chopped algebraically added amp vector X Y 1OmVp p em vert sensitivity Cont stale illumination w front panel control PA Hr P W x 15D 14 ibs af H
120. d 4 1 and 1 1 with fullscale ranges of 0 3 1 3 10 and 30 percent Accuracy 5 of fullscale Residual distortion 0 05 Harmonic distortion measurements at 20 200 200 2000 and 2000 20 000 Hz THD ranges 0 3 1 3 30 and 100 Voltmeter input impedance 2 megohms ranges 10 mV to 300 Vrms response 0 dB 10 Hz to 100kHz 3 dB at 300 kHz Decibel scale 20 to 2 based on 1 MW across 600 ohms AC MILLIVOLT METER has amplifier that can be used as a wide band scope preamplifier The Leader mode LMV 87A measures 1 MV to 300 V in twelve ranges Decibel range 0 dB 1 TAR AC Ni a wv g mW across 600 ohms Is 8 to 52 dB and bandwidth is 1 dB 10 Hz to 1 MHz Amplifier output is approximately 500 mVp p at fullscale Operates from 105 125 V 50 60 Hz around 50 Hz to 20 kHz For an instantaneous plot of an amplifiers response while checking the equalization curves the effect of tone con trols scratch and rumble filters cross over networks and for setting tape recorder bias we may use an audio generator with linear and logarithmic sweep outputs The generator sweeps the full range of say 20 Hz to 20 kHz The swept output of the generator is fed to the amplifier s tnput and the amplifier s output properly termi nated is fed to the vertical input of the scope The generator s internal sweep volt age is fed to the scope s horizontal am plifier The sweep can be linear each divi sion on the
121. d models of tape recorders projectors dictating machines video recorders and our simplified cross reference system makes it easy for you to order Drive tires wheels phono idlers also listed On most items we can ship the same day Call or write today for your free catalog cross reference chart PROJECTOR RECORDER BELT CORP 315 Whitewater St Whitewater Wisconsin 53190 414 473 2151 Circle 68 on reader service card sien to oe Send for FREE Tiger booklet 20 pages which answers all your questions Name Address City State n Zip CLIP OUT THIS AD AND SEND TO TRI STAR CORP P O Box 1727 Dept H Grand Junction Colo 81501 Circle 69 on reader service card ae LJ C LJ LJ O a O O E E O aes OOOU0 Best ZLAN ever made last word for stability of operation An opportunity to improve and bring your TV Re ceiver up to date FLYBACK TRANSFORMER We scooped the Market latest type standard for atl 130 TV s KCA s design of large Coil produces 18KV_2 assuring adequate width Incl Schematte Diagram application for any TV List price 13 90 3 3r lots of Your price 10 off in 116 TY DEFLECTION YOKE for all 49 TV s one sche matic E TIT SPECIAL RCA 110 FLYBACK 6 lus 110 DEFLECTION YOKE 0 r BACK TRANSFORMER for all 44 95 type TV s inc schematic 90 TV DEFLECTION YOKE for all type 2 TV
122. d cathode current Check the horizontal oscillator Do NOT try to read the pulse on the plate of a pulse regulator tube This is definitely a DO NOT MEASURE point you ll have the same pulse there as on the yoke around 5 kV To check this just hold the scope probe near it You ll have plenty of stray pickup to tel whether your pulse is normal Check a few sets that work to see about what kind of waveform you would see at this point Limit switches or lockouts in quite a few of the newer solid state color TV sets you ll find latching or lock out high voltage circuits used These will be triggered by a rise in high volt age When they re fired they disable some circuit In most of them it will stay off until the set is repaired One version kills the horizontal oscillator by killing its dc voltage supply A small SCR is used it s connected as a crowbar short across the 24 V This is fed by de when it is gated on it stays on The set must be turned off and left for about half a minute The charge leaks off the circuit and the SCR turns off So if you find a set where turning the BRIGHTNESS control up and down makes the raster go out this is probably what s doing it Check out the reg ulator which will be in the ow voltage sup ply in these chassis In some cases the SCR trips a little too fast Try a new one and see if there are any factory modifications to eliminate false tripping Resistors of course
123. d in Electronics 2 Your book on How To Get a Commercial FCC License I am especially interested in _ Electronics C Broadcast Electronic Technology Engineering Communications C Electronics C First Class 0 Industrial Electronics Technology FCC License with Laboratory Electronics Engineering Name Age please print Address City __State______ Zip Veterans and Servicemen C Check here for G I Bill information l amp Automation WITH THIS CONTROLLED OUTPUT SOLDERING STATION n Weller Model WTCP L Exclusive closed loop system of this 60 watt unit controls temperature output in three ranges 600 F 700 F and 800 F Tempera ture determined by selection of quick change anti oxidation coated heat sensing tips available in several types and sizes Easy to hold pencil grip iron with flexible non burning cord Power unit features rapid heat recov ery ON OFF switch red indicator light non sinking tool stand tip cleaning sponge receptacle Ask your focal distributor or write Weller Xcelite Electronics Division cooper P O BOX 728 INDUSTRIES Circle bl on reader service card The Cooper Group APEX NORTH CAROLINA 27502 report Technics By Panasonic SL 1200 Direct Drive Turn table Circle 56 on reader service card IN THIS AGE OF AUTOMATIC EVERY thing there are stil
124. d plons olso available PRONE or WRITE for CATALOG DIAL 402 987 3771 43 Fordham Radio Supply Co 6 _ F 26 Grantham School of Electronics Pe PARTS g GTE Sylvania Electronic Components Sa wv Send For Re 1X Heath Co aNs CORNELL S New Color A ORDER FREE Sn gt Indiana Home Study Institute m os Catalog IF NOT SHIPPED 1 N nternitional Components Carp Ta 48 iaa Gems IN TS OF 100 IN 24 HOURS x International Crystal Mtg Co 0 0 16 23 Jensen Tool amp at a 64 Judson Research amp Mfg Co gate 17 Leader 7a 2R MITS Micro Instrumentation Telemetry ji 74 G E 9T56Y8831 rated at 2 09 KVA 7 taps 14 a ee ees x ste Ad Be is E 2315r TOS m0 115 120 and 125 volts Input p90 voltage any voltage from 105 to 125 volts Output or 19 nisiiGanliCanienn Rm FA voltage any of the tap voltages above Currents in B a Ser 8 wees meine excess of 15 amperes per tap Ideal for raising or Sie R n ei lowering line voltages and getting 14 or 23 5 volts E at high current as well Many other voltage combin a ster e PALA Electronics E T ations possible we supply data sheet showing 4X Proiector Recorder Belt Co 0 8N many voltages possible with this transformer In Original factory PTS Electron K e Crer cartons Weight 12 Ibs ea 10 Quietrale Co STOCK NO J9868 10 00 ea 2 19 00 service tall RCA Electronic Components Test Equipment Cover ITI DUAL VOLTAGE HIGH CURRENT S ee wy T VARIABLE POWER SUPPLY KI
125. d rj T mae d pax 7400 24 7480 65 DNABOV EIN wae we om 50 ETCHED which will hold up 7401 24 7483 1 10 ER900 TRIGGER DIODES 4 1 00 to 21 single 14 pin IC s or 8 7402 24 7486 48 16 or LSI DIP IC s with bus Cpa 24 7489 3 00 LINEAR CIRCUITS 7405 26 7491 1 30 723 40 40V REGULATOR 75 nections Is als AS oe Bee ee ual 7406 43 7492 85 LM 300H REGULATOR POSITIVE 90 5 7407 50 7493 85 LM320 50r 15V REGULATOR 1 75 7408 27 7495 99 LM 376 V to 37V POS REG 1 25 FLV 100 VISIBLE LEO 50 JAIO 124 7496 95 741A 0r741C OP AMP 47 Ee egr ae ie E i 709C OPER AMP 47 P 9 n t DUAL 709 DUA A i GREEN GAP OSL 16 LED 90 7413 85 74123 1 00 101 OPER ee 1 Mieg To RED GAP OSL 3 LED _ 60 7416 48 74125 1 40 LM 308 OPER AMP LOW POWER 1 15 14 PIN DIP SOCKETS 40 Lae es ee te 747 DUAL 741 85 a 4 FET INPUT 52 10 WATT ZENERS 7422 30 74151 95 SS any PD 3 9 4 70R56Y 75 EA 7426 30 74154 1 65 LM 3900 QUAD OP AMP 75 4 WATT ZENERS 7427 55 74157 1 25 LM 324 QUAD 741 2 20 3 9 5 6 6 80R12V 30 EA 7430 24 74163 1 60 560 PHASE LOCK LOOP 2 95 7432 30 74164 2 05 561 PHASE LOCK LOOP 2 95 7437 60 74165 2 05 565 PHASE LOCK LOOP 2 95 7438 50 74173 1 80 567 TONE DECODER 2 95 7440 24 7417 7 80 703 RF IF AMP 65 7441 1 15 74181 3 95 LM 370 AGC SQUELCH AMP 1 15 7442 1 00 74192
126. d toa jack on the rear and by the setting of the range switch Fullscale frequency change requires about 1 volt input for either liner or log tuning Using the internal sweep source the generator sweeps the full frequency range in either a linear or logarithmic manner Sweep speeds are 2 5 ms 25 ms and 25 seconds Output High level sinewave variable up to 1 Vrms Low level sinewave is approximately 1 of the high level output setting Squarewave with 50 duty cycle at nominal TTL levels 0 to 0 5 V low and 3 to 4 5 V high Triangle output on rear panel 1 Vp p less than 2 mA peak current Operates from 9 volt battery NiCad battery and charger available as accessories AC VOLTMETER the Hewlett Packard 400GL features a 20 dB dynamic range on a 42 in linear scale and a single logarithmic voltage scale for mee ng 100 uY to 1000 Vrms fullscale in eight 20 dB steps Input im pedance is 10 megohms on all ranges The ac amplifier has a gain of 80 dB and delivers up to 1 volt rms open circuit for fullscale deflection Frequency response is 20 Hz to 4 MHz on 1 mV to 1000 V ranges 30 Hz to 100 kHz on 100 yV range A switchable 100 kHz low pass filter is provided to increase accuracy when meang low level low frequency signals The filter is switched in automatically on the 100 pV range A 10 1 voltage divider probe is available as an accessory to provide a low imput capacitaance at the point of measure ment Its response
127. device or When itis taking data in Two lines are pres ent on the CPU module IN and OUT These lines are used by the other modules to regulate the How of data in the correct direc tion at the correct time Fhe control of the IN and OUT lines is governed by the addi tional logic on the CPU module The Memory Address Manual Control module is used to hold data which is to be used as the memory address Two amp bit latches are provided since the computer will use one set of eight bits for a memory ad dress and the other set of eight bits for control functions Since the microprocessor can di rectly address up to 16 424 words of mem ory commonly noted as 16K we will need l4 binary bits for the complete address The complete memory address of any location is given by a 16 bit binary number X X Ba Ba B Bs Ba Bs Be Be Be Be Be Be Be Be where the X s represent bits that are not used The computer specifies any address by first sending out the Bz bits to one of the eight bit latches followed by the six Bs bits and two X bits Control of the correct latch is supplied from the CPU module The Ba bits have the most significance or value in the complete digit while the Be bits have the least significance This is like com paring 1000 and 1 The further to the left the digit in any numbering system the more value it has For this reason the Bs bits are culled the most significant or the HI part of the address while the Bz bits are
128. e a maaa ats jie ri Eoy gp YOU VE COME A LONG WAY KIN Gail Simione compares the RCA 15 V in line color TV tube system with the round 15 inch color tube system that many technicians will re member from the first sets sold in 1954 The new tube is smaller brighter and sharper and eliminates complex circuitry and difficult ad justments First reaching the market in 1954 color TV had no easy row to hoe Only 5 000 sets were sold in that first year and it was 1960 before a half million color sets were in use But 1960 was the turning point Increased color programming and greater availabil ity of color TV on the retail market com bined to more than triple the number to 1 7 million sets in 1963 Now there are 52 6 million sets in use 9 3 million were sold in 1973 alone and two out of every three homes in the United States has a color TV Integrated circuitry makes electronic watches practical The sharp upsurge in the demand for electronic watches due in no small part to the new digital types can be traced to the new COS MOS integrated circuits which make the digital readouts practical according to Harry Weisberg of RCA s Solid State Division These circuits he Says are so perfect for watches that it would almost seem that their original de signers had watches in mind The heart of the new watches like some of the older ones is a quartz crystal Oscillating at 32 kHz it is divided down to 1
129. e ae aoe eras LEADER ns INSTRUMENTS CORP Ag 669 95 With probes gn ali adapters leads eee ite ane Put us to the test Plainview L 1 N Y 11803 516 822 9300 Cirele 17 on reader service card 71 7 C f ati nal SERVICEMASTER sigs C International SERVICEMASTER The Money Making line with over 2000 types e The most com plete range of domestic and foreign consum er and industrial receiving tubes in the world Classic and antique too e Complete range of replacement semiconductors Discounted to give you higher profit margins e Quality your Customers can depend on For the name of your local distri butor call 516 293 1500 Or write International Components Corporation 10 Daniel Street Farmingdale New York 11735 Circle 8 oa reader service card appliance clinic by JACK DARR SERVICE EDITOR BATTERY CHARGES USED TO BE FAIRLY simple devices alow voltage transformer a rectifier and that was it They did the job but they could also do some damage Leave one on a battery too long and you re in trouble When a battery is partly dis charged a high current flows when the charger is hooked up As the battery charges up this current decreases How ever if the charger is left hooked up after the battery has reached full charge some current will still be flowing The actual amount depe
130. e control bits B C D and Dy ai and OR s them with IN to select the proper external data input port When the computer is instructed to get some data from memory it automatically selects the memory input section of the multiplexer The INPUT instruction is only used when you wish to input data from some external source such as a digital voltmeter or keyboard through one of the two input ports The Memory module uses the widely available 1101 type of semiconductor inte grated circuit memory The 1101 random access memory or RAM is organized as a 256 x bit memory so eight of the 101 type memories are used to give us 256 eight bit words This is the minimum configuration necessary for the Operation of the Mark amp Fach memory module can hold 32 of the 1101 memories for a total of 1024 or IK words of storage Up to four Memory mod ules may be used with the Mark 8 giving us a maximum 4K of storage space More than enough for most applications Each of the 256 words are addressed by the eight bits from the LO address latch Since 2 256 we can only address 256 words using the LO address alone Each memory also has un enable line so we may select blocks of 256 words using this line The HI address ts therefore used and de coded with a standard decoder and the de coded outputs are used to enable or select the blocks You do not have to be con cerned about the particular block where data has been stored just use the comp
131. e expensive and are not needed for one at a time arithmetic Op erations The rest of our calculator chip takes care of the housekeeping cycling the microprogram in the proper order taking care of con stants and decimal points accepting information into the keyboard register routing the display to a BCD to seven segment converter and the proper memory in the stack and so on What s available There are dozens of different calculator chips available today both as new and surplus items Some of these are now as low as 5 each surplus and quality new units in production quantities are pushing a 4 figure A few of the more common calculator IC s are on page 41 A list of some of the manufacturers is shown below A Few Calculator iC Manufacturers AMERICAN MICROSYSTEMS 3800 Homestead Road Santa Clara California 95051 CAL TEX SEMICONDUCTOR INC 3090 Alfred Street Santa Clara California 95050 GENERAL INSTRUMENTS 600 West Johns Street Hicksville New York 11802 INTEL CORPORATION 3065 Bowers Avenue Santa Clara California 95051 MOS TECHNOLOGY Valley Forge Center Norristown Penna 19401 MOSTEK 1215 West Crosby Road Carrollton Texas 75006 TEXAS INSTRUMENTS Box 5012 Dallas Texas 75222 As with any IC if you are building or experimenting with these be sure to have all data sheets and applications notes on hand before you start along with whatever other information you can possible get and r
132. e instructions KNOW YOUR ALPHA FROM THETA i For greater relaxation concentration listen to mea your Alpha Theta brainwaves Ultra sensitive J electrode headband slips on off in seconds eliminates need for messy creams etc Atch d to amplifier filters brainwaves signals beep for ea Alpha or Theta wave passed Monitor ing button simulates Alpha sound audio amp visual L E D feedback Reliable easy A to use unit comparable to costlier mod et Completely safe Comprehen instr bklt LOW COST Starter UNIT M Stock No 71 809E 0 49 95 Ppd SE 3 CHANNEL COLOR KIT Easy to build low cost kit needs no technical knowledge Completed unit has 3 bands of audio frequencies to modulate 3 independent strings of colored lamps i e lows reds middles greens highs blues Just connect hi fi radio power lamp etc amp plug ea lamp string into own channel max 300w ea Kit features 3 neon indicators color intensity controls con trolled individ SCR circuits isolation trans former custom plastic housing instr Stock No 41 831EH 17 50 Ppd MAIL COUPON FOR GIANT FREE CATALOG 180 PAGES MORE THAN 4 500 UNUSUAL BARGAINS 1 Completely new 74 Catalog Packed with huge selec tion of telescopes microscopes binoculars magnets magnifiers prisms photo components ecology and Unique Lighting items parts kits accessories man
133. e zero crossing 12 cm and within viewing area in normal mode Sync source channel 1 channel 2 or both polarity selectable or slope The CRT is an 8x10 cm flat face type The graticule is edge lighted IDEAL FOR STEREO is Leader s LMV 89 2 channei solid state millivoit meter The in trument features a single meter with two Inde pendent scales and separate pointers Espe claily useful where there Is a great difference in the voltage levels at the two points being me tered Individual switches and amplifiers are detector usually an infinite impedance detector that leaves the carrier whose am plitude is varying at a 60 Hz rate A low pass filter removes the carrier leaving only the modulation product The amplitude of the detected 60 Hz signal is read on the meter in terms of percentage of the high frequency signal passed through the high pass filter intermodulation measurements are usu ally made at different power levels up to the amplifiers maximum power rating Most IM meters often called analyzers include load resistors for the amplifier under test The instrument s panel meter can be used as a vivm to measure signal levels used in the test as a wattmeter to measure amplifier power output and to measure IM distortion The meter used is calihrated to measure the rms value of sinewaves so the non sinusoidal waveform resulting from the two tone IM test will have a value higher than the single frequency r
134. ead everything carefully Broken down into its component parts there s nothing really very fancy or exotic about a calculator except of course for the incred ible amount of engineering and expertise that goes into successful chip design Calculator 1C s are now cheap enough that you should be able to do much more with them than simple four functions arithmetic particularly if you add vour own external microprogramming entering in parallel with the key commands What applications can you think of R E GIVE somo ws ive HEART FUND WINEGARD AMPLIFIED PRODUCTS PROVEN IN OVER 1 000 000 INSTALLATIONS CASE IN POINT WINEGARD DISTRIBUTION AM Stirs For quality and dependability in distribution amplifiers look to Winegard You know they re good Because our distribution amplifiers have specs ycu can count on and the best reliability in the industry today When you install an MATV system you want it to work right and keep on working that way You want a headend amplifier that won t give you headaches No matter what size systems vou install Winegard offers the most trouble free circuitry around and at the most reasonable cost around On vour next commercial system start out with a Winegard distribution amplifier There s a model just right for every size and type of installation We invite LIFIERS comparison Best TV products for Best TV reception Wy WINEGARD TELEVI
135. ed without a speaker load this burned out the out put transformer Standard connections for this would be Pin common ground pin 2 4 ohms pin 3 8 ohms pin 4 16 ohms and pin 5 probably 500 ohm line HIGH VOLTAGE DROP With the switch in SERVICE position the high voltage is normal on this GE CA color chassis In NORMAL position it drops quite a hit and I have vertical retrace lines in the picture The horizontal scan also slowly collapses Would vou suspect the vertical output cirentis T replaced the vertical output tbe no help H K Chicago IH Not the vertical circuitry Fm afraid This kind of symptom is usually due to one of two things excessive beam current in the picture tube overloading the high voltage circuits or to a low output high voltage circuit which would include such things as the high voltage rectifier horizontal output tube etc Check the grid and cathode voltages on the picture tube in NORMAL posi tion of the service switch If the grids outduals EADER are too far positive or the cathodes too far negative the tube will draw too much beam current and overload the high voltage supply Maximum here is only S00 microamperes Check the set ting of the picture tube screen controls too If these are too high they can cause the same symptoms What you actually have is too much brightness This will almost always let retrace lines show ODD COLORS The picture
136. educed accu racy Basic accuracy 0 7 f s 1 of reading thru 100 V range Accuracy on t kV range is 0 7 f s 2 of reading Has 100 1000 10 000 100 000 ohm 1 and 10 megohm resistance ranges At low end measures to 0 1 ohm Accuracy is 0 5 f s 7 of reading through 1 megohm and 1 8 on 10 meg range Ac and de current 1mA to 1 Afs Minimum resolution 1 nA 3 2 x 7 Ye x 8 in 189 00 complete with combination handle tilt stand and test leads Data Precision Corp Audubon Road Wakefield Mass 01880 Circle 35 on reader service card FINE LINE SOLDER Cat No 9132 has low melt ing point and self feed plastic dispenser De signed for today s printed circuit needs this solder is 60 40 rosin core type and 032 inches in diameter Self feed dispenser holds over 12 feet of solder and is made of clear plastic so that the amount of remaining solder can be seen GC Electronics 400 South Wyman Rockford Ill 61101 Circle 36 on reader service card ANTENNA HARNESS mode JSL U is tapered line 300 ohm matching harness for combining idential uhf antennas into a single downlead Harness is ideal where vertical stacking of uhf antennas is required for increased gain and added vertical capture area Stacking gain is better than 2 5 dB theoretical maximum stack ing gain is 3 0 dB Can also be used as low loss mixer to combine two identical uhf antennas which are oriented in different directions such as ar
137. egative for npn If the pulse is fed to the emitter in a common emitter stage its polarity is reversed to that of a base pulse This is often found in hybrid or solid state sets Problems Now how about some of the odd prob lems that we can get from blanker troubles The worst ones are the type that cause a bias upset in the amplifier stage This causes ef fects not readily associated with blankers For the first one the older color sets using three color difference amplifiers with common cathodes for matrixing often had the blanking fed into the cathode circuit as in Fig The blanking pulse here is high negative going so that it causes cutoff of the picture tube It does this by making the color difference amplifier tubes conduct more heavily This causes their plate voltage to drop go more negative which in turn biases off the picture tube grids This kind of polarity reversal will be quite common and confusing so watch out for it What happens if the blanking pulse is R Y 2 RED GRID er Or 405V GY GREEN GRID 405V 270V B Y BLUE GRID 405V l 7 0V FROM BLANKER m alt BIAS 2702 FIG lost In this ctreuit we lose the raster The presence of the large blanking pulse on the cathodes of the color difference amplifiers develops a bias of about 7 volts Without the pulse this drops to a very low voltage less than 1 0 volt The triodes conduct very heavily and the picture tube cuts
138. egulator was doing nothing so the high voltage went up to around 30 kV This was due to a faulty resistor Diode clamp and hold down circuits can be tested in the same way Check to find out exactly whar the thing is doing Does it have normal high voltage very low high voltage or what Read the grid voltage of the hori zontal output tube In most sets this will be about 55 to 60 volts If you read 100 volts or even more you have some kind of trouble in the grid bias circuitry See if you read a higher negative voltage across the control diode than you get at the grid You can ground the bottom end of the horizontal output tube s grid resistor If this brings the grid voltage back to almost normal check the bias control circuits Check diodes for leakage or opens also since the control voltage is developed across the little capacitor as a negative charge check this for an open Scope the diode to see that the flyback pulse is there Average amplitude runs around 200 volts p p The key tests for trouble in this circuit will be both the high voltage itself and the cathode current of the horizontal output tube If you see low high voltage and the cathode current is also well below normal say about 100 mA 200 mA is normal aver 62 age this would point to a weak horizontal Output tube low dc voltages or something in that area Low grid drive on the horizon tal output tube will show low grid voltage and increase
139. el Fast B hr Service NEW YORK NEW YORK ciry new Jersey WHI take care of your tuner problems like no one else can WE RE PROFESSIONALS TEL 201 791 6380 CHARLOTTE N C 28205 5682 STATE RD OKLAHOMA All Makes TEL 405 947 2013 transit to one of our plants VHF or UHF 9 95 PORTLAND OREGON 97213 3 Lower Cost Up to 5 50 Jess than other tuner companies 1921 S 70TH ST PENNSYLVANIA WEST PTS ELECTRONICS INC is recommended by more TV manufacturers and TEL 412 761 7648 TEXAS NORTH MOPAC LANE LONGVIEW TEX 75601 TEL 214 753 4334 AND STILL TRYING HARDER NOT A FRANCHISE COMPANY Circie reader service card HI Fi STEREO SERVICING GUIDE 2nd Edition by Robert G Middleton Anyone servicing a m tuners fm tun ers stereo multiplex units and audio amplifiers can gain valuable service direction and assistance from this ins guide It also covers hi fi Speaker in stallations system evaluation trouble shooting and methods of verifying test equipment performance 104 pages softbound No 21075 4 50 LW TTL COOKBOOK i ix X by Donald E Lancaster rT NA G 3 Transistor Transistor Logic has opened 3 Cookbook Te up a fantastic number of applications MONUU mti z AS for digital circuitry It is not only bet a EE eee Gore y ter than traditional analog circuits it is often cheaper This timely book by hy a the author of the famous ATL Cook x So SS Sy PF
140. essons present facts and concepts in small easy to understand bits reinforce them with clear explanations and examples Students learn more thoroughly and faster through this modern simplified method You too will absorb retain advance at your own pace Employment Assistance available for all CIE students at no extra cost Once enrolled with CIE you will get a bimonthly listing of high paying interesting jobs available with top companies throughout the country Many CIE graduates hold such jobs with leading companies like American Airlines AT amp T General Electric General Telephone and Electronics IBM Motorola Penn Central Railroad Raytheon RCA Westing house and Xerox to name a few CIE Lessons are continually up dated All lesson books and materials from CIE are continually revised or replaced according to the current needs of indus try and the rapidly advancing and changing state of the art Approved Under G I Bill All CIE career courses are approved for educational benefits under the G 1 Bill If you are a Veteran or in service now check box for G I Bill information ci Cleveland Institute of Electronics Inc 1776 East 17th Street Cleveland Ohio 44114 Accredited Member National Home Study Council Mail coupon for 2 FREE BOOKS Cleveland Institute of Electronics Inc 1776 East 17th Street Cleveland Ohio 44114 Please send me your two FREE books 1 Your school catalog Succee
141. following order kit s of electronics only Modei CK 100 68 00 each cabinet s with face and mounting hardware Model C 31 18 00 each factory assembled calendar clock s Model EC 102 108 00 each Add 3 UG to cover costs of postage and handl ng New Jersey res dents add 5 9 Sales Tax Name Address City State 74 or KEYBOARD ENCODER 48 Keys ASC II Encoder For Computers Terminals TV Typewriters Calculators RTTY Displays CATV and more At long last a top quality fully pro fessional data entry keyboard at a sensible price Keyswitches are full typewriter travel and response type arranged in a modified ANSI lay out Full length spacebar with equalizer Keyswitches are mounted on a double sided fiberglass circuit board with plated through holes The encoder provides a standard ASC II output and includes a de bouncer circuit ASC Il code in cludes shift and control functions with two user defined keys available Keytops are first quality double shot molded types for permanent good appearance Gold plated con tacts on keyswitches NEW no sur plus parts Typewriter style NOT a modified kKeypunch board This keyboard is ideal for use with the Radio Electronics TV Type writer or any type of raclio tele type display ststem It will drive The DTE BEE CMOS and PMOS logic systems Requires only 5 Volts 100 Ma Circle our reader service number below for a FR
142. from 100 Nano Amps to 1 Amp 77 00 Case ex 12 50 Optional probe 5 00 40 MHz DIGITAL FREQUENCY COUNTER e Will not be damaged by Figh power transmission levels e Simple 1 cable connection to transmitters Output ES 220K Line frequency time base 1 KHz resolution 5 digit 69 50 Case extra 10 ES 221K Crystal time base 100 Hz resolu tion 6 digit 109 50 Case extra 10 00 DIGITAL CLOCK v ee ES 112K 124K 12 hr or 24 hr clock 46 95 Case extra Walnut 12 00 Metal 7 50 CRYSTAL TIME BASE ES 201K Cptional addition to ES 112K 124K or 500K Mounts on board Accurate to 002 D REMINDEF ES 200K Reminds operator 9 min 45 sec have passed Mounts on ES 112 or 124 board Silent LED flash 10 95 Optional audio alarm 4 00 extra Dependable solid state components and circuitry Easy reading 7 segment display tubes with clear bright numerals These products operate from 117 VAC 60 cycles No moving parts Quiet trouble free printed circuit Each kit contains complete parts list with all parts schematic illustrations and easy to follow step by step instructions No special tools required i ORDER YOURS TODAY Use your Mastercharge or Bankamericard Money Back Guarantee D418 La Cienega Inglewood Ca 903904 249 674 307 80 Circle 28 on reader service card supply transformers in some new TV sets Sepa rate function is provided for ac peak to peak
143. g and retexturing molded plastics shrinks vinyl to fit upholstery Sturdy adjustable metal stand permits positioning on bench or machine on assembly lines etc MILWAUKEE LOCK amp MFG CO 5078 WN 37TH STREET MILWAUKEE WIS 53205 92 Circle 75 on reader service card IN 1317 293 S827 Ay INi 1315 446 0770 CAME 1514 731 93276 new books ELECTRONICS FOR MODERN COMMUNICATIONS by George J Anger bauer Prentice Hall inc Englewood Cliffs N J 6 1 4 x 9 1 4 in 662 pp Hardcover 15 95 If you are Seeking an amateur or FCC commercial license this text provides the latest information that you need to prepare for the license examination Chapters include transistors and other solid state devices reflecting the latest FCC type questions Sample questions follow most chapters and have been compiled following the latest FCC Study Guide Revisions New circuits have been included wherever possible to Show the changing nature of electronic communications TRANSISTOR SPECIFICATIONS MANUAL 6th Edition By Howard W Sams Engineering Staff Howard W Sams amp Co Inc 4300 W 62 St indianapolis ind 46268 8 1 4 x 10 3 4 in 160 pp Softbound 4 50 This manual contains three main sections designed to provide a max imum of information about the transistor a Specifications section a lead identification section and an outlines section It also includes a special listing of Specifications for rf power transistors Using t
144. ge there d be a lot of different possible ways to do the job But when we take all these restrictions into account and at the same time aim at circuitry that eventually will sell for 19 95 or even 9 95 there s only one really good route to do the job While best current pricing is still 29 95 and up the inner workings and mechanical complexity of a 4 function calculator is far less than a 4 transistor radio What is the best route to do the job It s based on several circuit principles e Serial by digit arithmetic e Repetitive use of a simple unsophisticated arithmetic unit to do complex functions e Use of a multiplexed display e Use of a scanning keyboard e Use of a dynamic shift register stack to store inputs calcula tion products and answers Let s look at these one at a time Starting with the simpler con cepts and then going on to put the whole thing together as a working system Multiplexed displays Our display typically consists of a group of light emitting diodes LED s or an arrangement of neon display characters although some calculators also use miniature fluorescent display tubes or liquid crystal readouts Regardless of the method we use we have to select a means of driving the display that has a minimum need for 38 HF ee i i f y E by by ay a ky ey E 3 F ot Se bil bt bea ok be bal j u Fia b pa maen a Sa o Sy Epio a i EL AATA eLa aA ja ey a S TP et pi 2 p rap p T t if Tee
145. ging from 20 dBm to 30 dBm Input im edance 400K ranges are 30 10 3 1 0 3 and 1 percent fullscale for rumble wow and flutter measurements Accuracy is 0 01 The 3 kHz test oscillator delivers 1 5 volt into 120K 35 mV into 600 ohms and 10 mV into 250 ohms The instrument can be used as an audio voltmeter with 400K input impedance and fuliscale ranges of 1 mV to 100 Vrms in eleven 10 dB steps Frequency response 6 dB pein is 0 3 Hz to 100 kHz The 10 to 2 dB scale is referenced to 1 mW into 600 ohms Powered by eight C cells ALL SIGNALS REQUIRED FOR FM STEREO and monophonic alignment and troubleshoot ing are supplied by the Heathkit G 37 FM stereo generator Generates mono FM or com posite multiplex stereo FM signals a phase test signal composed of left and right channeis in phase a crystal controlled 19 kHz pilot ad justable from 0 to 10 for checking receiver lock in range and a selection of 400 Hz 1000 Hz 5000 Hz 19 kHz 38 kHz and 65 or 67 kHz for complete alignment of decoder circuitry in ad dition the IG 37 delivers a 100 MHz sweep signal adjustable 2 MHz for overall rf and if alignment and provides crystal controlled 10 7 90 95 96 30 101 65 and 107 MHz mar kers for i f and dial tracking checks Sweep width adjustable to 75 kHz Rf output level variable in three 20 dB steps Operates from 105 125 210 230 V 50 60 Hz lines IN LINE READING DIALS show attenuat
146. h AUGUST 1974 Build A 35 Infrared Viewing System It s easy to build and literally makes it possible for you to see in the dark A great project for the experimenter Security System Installers A new job for the technician Forest Belt explores the job of the security sys tem installer Discover if this is a field worth getting into it is Learn what you must know to enter this profitable field ABC s Of Public Address A short review of the basics that must be remembered to set up a proper PA sys tem Designing Output Transformerless Output Circuits How to design one that will be sure to work Its a useful circuit but must be handled with care Tunnel Diode Theory amp Circuits A delightful article that does more than just explain how and why tunnel diodes work It concludes by showing how to assemble a wireless FM mike PLUS Technical Topics Appliance Clinic Jack Darr s Service Clinic R E s Transistor Replacement Guide a _ aii a R UNDERSTANDING CALCULATOR IC S continued from page 41 library or Electronic Design 50 Essex St Rochelle Park N J 07662 With 500 or so machine cycles available each second we can use rather sophisticated algorithms and still come up with an apparently instant answer to a tough problem Minicomputers and regular computers use parallel computational systems with much faster machine cycle times of fractions of a microsecond These are much mor
147. he drive system This Is a good time to inspect the belts they are probably cracked and it s worth while to replace them now when it s easy and convenient In any case make a note of how many there are and also copy down all the information you can find about the recorder from the chassis and case A simple sketch taped to the bottom of the transport can save you a lot of head scratching if you have to replace a belt later Strip out any electronic components you can remove This lightens the re winder and you might be able to reuse some of the salvaged parts Leaving the steel guide pins the capstan with its roller and one pressure pad take off all the rest of the components that the tape passes over including the erase and record playback heads With the re maining pressure pad held away from the tape what s left should cause enough drag to keep the tape from flut tering during fast rewind If it does not lower the pad and adjust the spring ten sion until the tape will run fast and smoothly Keep the pad moist with tape lubricant Leave the counter hooked up its handy for editing You might be able to make the rewind unit smaller by making a simple case just the size of the deck covering the box and deck with contact paper for a quick finish Complete your modification with knobs on any unused exposed control shafts as well as the functioning ones for appearance Gene Cabot Poly Paks 4 in
148. he police departments of Tallahassee and Jacksonville in Fla in Abilene Tex and Grand Rapids Mich as well as over the whole island of Jamaica One of the police departments reports that a 22 de crease in burglaries can largely be cre dited to the use of Scramblers Computer aided stimulation brings light to blind A wave of articles in newspapers and magazines recently told of experiments in which two blind persons were able to see spots and patterns of light Readers of this magazine who have been following the results of such experimental work since 1958 may have been puzzled as to what was new in the work described It did however represent significant advances as well as wider study of fields previously partly explored The approach of the researchers W H Dobelle and M G Mladejovsky of the Uni versity of Utah and J P Girvin of the Uni versity of Western Ontario was to place a matrix somewhat similar to the mosaic ofa TV camera against the portion of the subject s brain that responds to light Stimuli This array of 64 platinum disc electrodes 1 square millimeter each in diameter arranged in 8 rows of 8 discs was Similar to that used by Brindley and others in England A small window was made surgically in the skull to insert the electrodes IN was then closed in such a way that the matrix could be removed without reopening the incision The new technique was the use of continued on page 1 4 BOEING
149. he result as the percentage of totul harmonic distortion or THD The harmonic distortion meter is a rela tively simple instrument as indicated by its block diagram in Fig 2 A low distortion audio oscillator is connected to the input of the amplifier being tested and the analyzer is connected to the preamp output or in the case of a power amplifier across a dummy load resistor equal to the amplifier s output impedance The oscillator is set to a test frequency and its output level adjusted to within the range of the amplifiers input rat ing The harmonic analyzer mode switch is set to CALIBRATE and its sensitivity or level set control is adjusted so the analyzer s meter reads 100 the level to which the har monic level is compared When the meter is switched to MEASURE a Wien bridge or FIG 2 BASIC HARMONIC METER Instrument is calibrated at the test frequency and then a tunable filter is switched in and adjusted to null the test signal Meter reads distortion tf FUNCTION HF o CONTROL GENERATOR 3 608 7 kHz WATTMETER CORRECTION f NETWOAK LOW PASS ANALYZER FILTER ae _ AN LFA TEST SET TPUT Mi a LEVEL meee IM T gt viv FIG 3 BLOCK DIAGRAM of the Heathkit audio analyzer used for intermodulation measurements The instrument also functions as an audio vtvm and as an audio wattmeter 35 similar active filter is inserted in the
150. hinline 1 6 x 9 HEAVY DUTY 10 O2 8 98 SPEAKER Ceramic Type 8 Ohm 10 ASSORTED DIODE CRYSTALS INN IN60 INGI ete 6 TOP BRAND SILICON RECTIFIERS amp 1000 PIY PNP TRANSISTOR general purpose Ti 5 case 5 NPN TRANSISTORS general purpose TCS case 25 ASSORTED TRANSISTORS hig fac Lory scoop sold as is TV TWIN LEAD IN 300 ohm S00 i S0 oY t0 MINIATURE ELECTROLYTIC CONDENS 1 ERS For Transiator amp miniature work 20 SHIELDED TWO CONDUC TOR CABLE Cires 1 TOSHIBA CASSETTE DECK Record amp P Whack Model 95 K f 319 8 ELEMENT COLOR OUTDOOR AN 5 95 TENNA Biz shot Jr List 11 95 4 POLARIZEO CHEATER CORDS 1 Cores CONDENSERS 1 ae ae 1 1 1 1 7 100 LJ e T ea TRAE 25 SHIELDED MICROPHONE CABLE 25 Cites 4 ELECTROLYTIC 75 mfd 150 TEST EQUIPMENT SPECIAL DISCOUNT PRites Leaner SENCORE Minimum Order 3 00 Please specify retund on ihippino overpayment desired CHECK POSTAGE STAMPS MERCHANDISE our choice with advantage to customer BROOKS RADIO amp TV CORP 487 Columbus Ave New York N Y 10024 Circle 70 on reader service card 212 874 5600 TELEPHONE 89 Save hundreds of dollars in alarm installation and monthly service charges The EICO SS 500 install it yourself burglar fire alarm sys tem offers you the kind of professional protection you have been look ing for at a price you can afford The S
151. hipment will be made via first class mail pastage paid in U S Canada and Mexico within three days from receipt of order Minimum order 5 00 California residents add sales tax INTERNATIONAL ELECTRONICS UNLIMITED P O BOX 1708 MONTEREY CALIF 93940 USA 95 MC4005 SCRATCH PAD MEMORY IC 1 25 16 FLIP FLOPS IN A 4 BY 4 MATRIX DOUBLE RAIL READ amp WRITE SEVEN SEGMENT READOUTS MAN 3 STRAIGHT LEADS SUPER SPECIAL MANESM EUAW TYPE eee e eeraa ti eea 1 20 MAN 4 DIP A EE ES 1 93 MAN 1 THE REAL THING eee cr eae 3 33 MAN 1A LATE VERSION oe eee ee 3 79 DL 707 UNIVERSAL LED READOUT 2 45 B7971 HUGE 4x2 NIXIE BRAND NEW CLOCK SCHEMATIC INCLUDED 1 50 4 FOR 5 50 6 FOR 50 SOCKET FOR B7971 USED Seer ee ee 40 OM7880 00 700 B7971 DRIVER wn 1 95 MY 50 LED RED 7 FOR 1 00 NSL 100 LED RED aoaaa eee FOR 2 00 MY 2 LEO GREEN 4 FOR 2 50 7400 7401 7402 7403 7404 7410 7420 2 7430 7440 7450 7453 7454 7460 aaa oe 7496 74L00 74102 74103 74104 74L10 74120 74130 7451 39 74408 50 7473 744174 75 74186 PANG 74t93 TALIS o a aa 1 65 743206 MEMORY IC os cs ceed cen deca 3 75 BIPOLAR TTL RAM 11256 10 FOR 30 00 3 CHIP ENABLE LINES FULL QATA FURNISHED 8223 FELO PROGRAMMABLE 256 BIT ROM 6 95 CUSTOM PROGRAMMING 0 2 ee eee 5 00 8424 LO POWER OUAL RS T FLIP FLOP 12 FOR 5 00 INCLUDES SPECS amp MANY APPLIC
152. his manual you should be able to determine the essential electrical and mechanical specifications of more than 4000 transistors ELECTRONICS SHOP PRACTICES EQUIPMENT AND MATERIALS by Clyde N Herrick Prentice Hall Inc Englewood Cliffs N J 6 1 4x 9 1 4 in 340 pp 14 95 Any technician in training or a technician employed in the areas invoiv ing assembly techniques assembly line testing quality Control or tuning calibration processes will find this book most useful Demonstra tions and projects combined with more than 300 illustrations provide invaluable hands on experience as well Starting with safety rules basic tools and equipment the text goes on to cover parts identification hardware and test equipment KITS amp PLANS by Joseph Rosenbloom Oliver Press 1400 Ryan Creek Road Willits California 95490 8 1 2 x 5 1 2 in 274 pp Softcover 3 95 More and more people are building things for themselves these days As a result there are more and more kits and plans available The problem is how to find out who makes what kit or plan This guide is essentially an attempt to ease the problems faced by anyone who wants to find out who makes what kit Those companies that supply kits or plans have been located and identified Their catalogs have been analyzed and their proj ects or products have been broken down into useful Categories Look up a product in the index and you ll find out what companies offer kits or plans for
153. hoto of the 900 quadriphonic receiver its function and mode of operation is quite different from that of meters normally called signal strength tuning meters Typically conventional signal strength meters obtain the voltage necessary for their pointer s deflection from either an 1 f age voltage which of course Increases with increased 48 by LEN FELDMAN signal strength or from a rectified por tion of the 10 7 MHz if signal ob tained at the output of the first or sec ond limiter in the FM Lf system as shown in Fig 2 The disadvantage of this kind of signal strength indicator is that it is difficult to determine the exact center of channel point because the FIG 1 FRONT PANEL VIEW of Harman Kardon model 900 quadriphonic recelver LIMITER STAGE A n Bi FIG 2 CONNECTION POINT FOR TYPICAL signal strength FM tuning meter maximum indication follows the typ ical limiter voltage curve which in a wideband limiter has a poorly defined and broad maximum value Further more maximum indication on this type of meter does not necessarily corre spond to best received audible signal if by best received signal We mean the signal tuned to greatest degree of quiet Ing Ratio detector circuits used in mod ern FMi tuners lend themselves to a fairly simple metering system which works better for center of channel tun ing Since the ratio detector circuit shown in Fig 3 has a de outpu
154. ically resistant sound absorbing feet The mounting feet have a moderate height adjustment which permit precise horizontal balance of the pickup arm JVC CD 1668 Cassette Deck Features New Noise Reduction System Circle 87 on reader service card WITH THE INTRODUCTION OF THE JVC automatice Noise Reduction Svstem termed ANRS the audiophile now has available two anti noise systems which do not degrade a tape recorder s overall frequency response In many respects the ANRS is similar in basic operation to the Dolby and as we ll show both ANRS and Dolby tape recordings can be inter changed with a reasonable or acceptable degree of matching As with the Dolby the ANRS is a closed loop system all circuits between the input signal encoder and output signal de coder are included in the anti noise processing the tape the playback preamp lifier and the playback line amplifiers up to the decoder These circuits represent the inherent tape noise the transistor noise from the amplifiers and the bias noise aris ing When electrical signals are converted to magnetic variations all of which appear as a background hiss Also silimar to the Dolby a single equalizer circuit functions for both encoding and decoding so that the overall record play frequency response is optimally Hat In the record mode the input signal is passed through the high frequency boost equalizer which is connected in parallel with a
155. ice president for research and development it can potentially be made fora fraction of the cost of a conven tional television camera Immediate ap nlications according to Dr Bueche in clude surveillance as on military bases and other high security installations banks museums and businesses As the Camera is improved the field of applica tions will become wider and it might be combined with a small video tape recorder and a home television set to produce in stant replay home movies Mobile telephone scramblers cut down profits of crime Much of the value of a police radio sys tem is lost if criminals can eavesdrop on it Burglars narcotics dealers car thieves and others find it worth their while to in vest in the relatively simple and inexpen sive equipment needed to follow the police radio Plain language transmis sions become little more than broadcast programs attempts at secrecy by using word and number codes are almost useless even the police buffs under Stand them A new 7 pound mobile phone Scram bler does foil the villains Mounted in the trunk of a police car with a mode selector on the dash it makes the radio messages a hash of meaningless gabble except to a receiver set to the same code And unauthorized unscrambling is made more difficult by the fact that there are more than 200 000 possible codes Boeing Electronics manufacturer of the Scrambler reports that they are in use by t
156. ignal The amount of distortion or the flatness of the generator s output over the tuning range is of little importance at the moment On the other hand an audio generator used for measuring or tracking down distor tion measuring frequency response the re sonant freqency of speaker enclosures and checking input and output impedances should deliver a signal with distortion li mited to0 5 or less over the range of 20 Hz to 20 kHz and preferably to 50 kHz Output versus frequency should be dB or better from 20 Hz to 20 kHz or higher 34 Modern hi fi equipment is more sophisticated and complex equipment and exacting procedures to service it Most audio generators are R C types using either phase shift or Wien bridge cir cuits to cover a tuning range in four or five bands with 10 1 or 100 1 tuning ratios Some function generator type audio signal sources cover the range of 20 Hz to 200 kHz in only three bands Output impedance ts generally 600 ohms unbalanced 600 ohm is a figure designed to match long audio lines When driving high impedance loads most manufacturers recommend loading their generators with a 600 ohm resistor Most audio generators have a step at tenuator calibrated in decibels followed by an output level control for adjusting the out put from maximum down to zero Note that most the attenuators included in these in struments do not have the fine precision ad justments of output level that are re
157. ing from the various com binations of fundamentals and second har monics are 2 60 120 Hz gt x 7000 1400 Hz 120 7000 7120 Hz 7000 120 6880 Hz 14000 60 14060 Hz 14000 60 1300 Hz 14000 120 14120 Hz 14000 120 13880 Hz A block diagram of a typical IM meter is shown in Fig 3 The 60 H2 test signal is tapped off the power transformer the high frequency signal is supplied by an internal audio oscillator Level controls are provided so the 60 Hz signal can be adjusted to four times the amplitude of the high frequency signal for the standard4 I ratio or for a ratio as high as 10 1 depending on the test stan dard you are using The two signals are mixed and fed to the amplifier s input The signal is taken off the amplifier s output and fed into the analyzer circuits in the IM meter A high pass filter removes the 60 Hz signal leaving only the high frequency signal call it the carrier along with any possible 60 Hz modulation The carrier is then rectified by a linear 4 IM DISTORTION 5 3 25 3 75 4 25 4 75 5 25 5 75 INCHES FROM CENTER FIG 4 IM RISE due to a worn Stylus 36 FUNCTION GENERATOR the model 30 by Wavetek covers 2 Hz to 200 kHz in three over saa 1000 1 ranges 2 Hz to 2 kHz 20 Hz to 20 kHz 200 Hz to 200 kHz delivering sine square and triangular waveforms Can be used as a vcg voltage controlled generator with the frequency controlled by a voitage apele
158. ion and layout Information is included on wire wrapped interconnections preparing layouts methods of building prototype boards and how to sys tematically wire projects DIGITAL HANDBOOK G C Electronics Co 400 South Wyman St Rock ford Ilt 61101 5 1 2 x 8 1 2 in 64 pp Softcover 50c Basic fundamentals for the digital integrated circuit with charts schematics and eight easy to build projects for the hobbyist and experi menter are featured These projects include a digital dice game digital clock digital burglar alram and others All are complete with parts lists and construction details R E 7400 DI 7400 25 74H00 a Three digits with right hand decima 7401 a Plugs into DIP sockets 7402 u Similar to LITRONIX DL337 74H01 a Magnified digit approximately 1 7403 a Cathode for each digit 7404 a Segments are parallel for multiple 74H04 operation 7405 n 5 10 MA per segment Bee 0G EACH 3 95 4 12 Digits 13 00 74H05 7408 RCA 2010 74H08 Numitron Digital Disoslay Tube incan 7410 descent 5 volt 7 segment 74H11 o 6 High numeral visible from 30 ft 7413 a Standard 9 pin base solderable 7417 n Left hand decimal point 7420 74L20 EACH 5 00 5 FOR 20 00 74H20 74H22 CT5005 a singie MoS chip with 7430 all the logic necessary for al2 digit 74H30 four function calculator with an ex 74L30 tra storage register for constant or 7440 memory applications 74H40 28 Lead DIL package 744 Standard 9 pi
159. ion ata glance on the Hewlett Packard 4436A shown and 4437A decade attanuators Both have a maximum attenuation of 119 9 dB in 0 1 dB steps Frequency range is dc to 1 5 MHz 0 to A aial ET F L a fi E nou oA ke r iib atigH ATOR 5 y gece MaS 110 dB and dc to 1 0 MHz 0 to 119 9 dB input and output impedances 600 ohms balancedin the model 4436A and unbalanced in the 4437A Maximum input power is 1 wart 24 5 V max imum WOW AND FLUTTER METER features a sepa rate panel meter for measuring drifi in tape speea Drifttestrangets 5 2850 Hz to 5 3150 Hz in one range The Leader LFM 36A measures wow and flutter in 0 1 0 3 1 and 3 push button selected ranges Can be used with scope to observe wow and flutter content input signal level is 15 mV to 10 Vrnis Input impedance is over 100K unbalanced A 3 kHz test source is included in this instrument Op erates from 115 235 V 50 60 Hz COMPOSITE AUDIO OUTPUT for direct injec tion into multiplex decoder as well as for mod ulating the 100 MHz carrier with deviation up to 75 kHz is generated by precision circuits in the Eico 242 FM multiplex signal generator Chan nel separation is 40 dB from 200 Hz to 10 kHz 30 dB from 50 Hz to 15 kHz Composite signal out put is continuously variable from 0 to 8 Vp p at 1500 ohms Internal modulation 1 kHz with less tnan 0 3 THD External moduiation 1 V rms into 10 000 ohms for 100 modulation Stereo so
160. is 0 to 10 MHz The 400GL operates from 115 or 230 volt 48 to 440 Hz lines Terminals on the rear panel are for optional operation from batteries delivering positive and negative voltages between 35 and 55 volts DECADE ATTENUATOR model 1450 TB by General Radio has an attenuation range of 111 dB in steps of 0 1 dB and handles up to 1 watt Each ofthe three decades has eleven positions 0O to 10 inclusive so the ranges overlap Frequency discrimination less than 0 1 dB 1 of indicated value for frequencies below 200 kHz For increments in attenuation the 1 tolerance holds out to 1 MHz impedance is 600 ohms in either direction An etched calibration chart indicates mis match losses for circuit impedances other than 600 ohms Each decade is individually shielded with the shields connected to the panel and a ground terminal The decade attenuatoris also available as the model 1450 TBA for rack mounting WIDE BAND AMPLIFIERS are featured in the Heathkit ID 101 electronic switch Each chan nel has 1 mehohm 50 pF input impedance Re sponse dc to 5 MHz 1 5 dB 3 dB gain is greater than 10 Minimum input signal 50 mV maximum 600 Vp p or dc Maximum output 8 Vp p Chopping rates approximately 100 500 1000 and 5000 Hz Hum and noise single chan nel only less then 40 mV p p WOW AND FLUTTER measurements can be made with any Carrier in the range of 2 kHz to 8 kHz with the Manke model M 1 at input levels ran
161. istors Blanker transistors are found in most hy brid and solid state sets Like all of the rest they can cause some unusual Symptoms In Sylvania s D 1 color chassis a bad blanker transistor can cause a series of faint vertical lines to show up in the raster Scoping the blanker transistor will show you the same signal on both base and emitter quite low in amplitude This happens when the transistor is leaky If this transistor should open the roaster will still be there but it will turn purple Don t ask I know not why but it does Another jail bar symptom but this time affecting only the color shows up in circuits such as Zenith hybrid 14Z8C50 chassis The B W picture will be good but when you turn up the color control you get a jail bar effect in the color Here again the cause Is a shorted horizontal blanking diode This time it is in the emitter circuit of the second color bandpass amplifier transistor The reaction Is just the same as before the shorted diode allows the ringing on the baseline to get hhrough and blank out only the color signals Fig 4 shows this one FROM i 1ST CHROMA AMPL TO COLOR KILLER CONT 2ND CHROMA BANDPASS AMPL 121 587 p F gt 562 10K ae 1W HORIZ PULSE PULSE GATE 2 2K FIG 4 1 3 Stand ae 6MN8 GRID e 8 Dz 405V 7 ue GREEN aa eS GRID 405V 270V B Y Ve BLUE 6MN8 GRID 2 4 405V 10 13V FROM FLYBACK ie 12K SK HORIZ BLANKE
162. it In fact this current rises slightly more than it would if all of these were standard resistors This is because of the reduced resistance of the thermistor with increased current Its resistance drops so does the voltage drop across the bottom section of the di vider This results in the SCR gate becom ing not quite positive enough to be turned on So it blocks current flow and the bat tery will not be over charged This won t be a complete cutoff The meter will generally flicker slightly The Zener diode and the re sistor across the supply also help out in this action by providing a fixed reference vol tage What to do if it doesn t work The old standard test that we used to make to see if a battery charger was work Ing was popping the clips together to see if there was a Spark don t think I d recom mend this any more Solid state devices dis like any transients so don t take chances In most of these chargers you will have a panel ammeter This will tell you whether any current is flowing or not Connect the clips to the battery If you see an indication of current on the meter OK Many of these chargers have a clever little reverse polarity indicator circuit which tells you if you have managed to connect the battery up backward This is the diode and lamp shown across the de output If the bat tery is hooked up correctly the cathode of the diode has a positive voltage applied to it It won t conduc
163. ither way across the bad diode A normal diode reading is a very low resis tance one way and a very high resistance with the chmmeter prods reversed R E SOLDERING IRON CORD HOLDER If your workbench is usually clut tered with small parts and tools you have probably often gotten your solder ing iron cord tangled up in something and pulled it to the edge of the table and watched it crash to the floor A way to prevent this is to use a gadget that the little women may be using on her iron ing board These were intended for use on the end of an ironing board to pre vent ironing over the cord etc but works equally well holding the solder ing iron cord up out of the way The holder installs on the edge of a table or work bench and is secured by a thumbscrew Kent Mitchell W3WTO CATALOG of over 1500 unusual tools A carefully selected and tested assortment of unique hard to find tools clever gadgets precision instruments bargain kits One stop shopping for the technician craftsman hobbyist lab specialist production supervisor Many tools and measuring instruments available nowhere else One of the most unusual and complete tool catalogs anywhere Get your copy of the NC FLASHER today National Camera ATS 2000 West Union Ave Dept GBC Englewood Colorodo 80110 um 303 789 1893 Circle 19 on reader service card ELECTRONIC TECHNICIANS Raise your professional standing and prepare for prom
164. ket flipover needle 1 ELECTROLYTIC CONDENSER Mo Mfd D0 RANS 1 1 15 MINIATURE 456KC IF FORMERS PC 2 X 4 good value 2 12BH7 RCA TUBES ELECTROLYTIC CONDENSERS 1 D0 Aan aw Mfg ADY 2 ELECTROLYTIC CONDENSERS lium 1 mfd 35V 1 5 SPEAKER with output trans 1 39 former MERCURY TUBE TESTER MODEL 39 95 Compact latest model MIDLAND STEREO AMPLIFIER Medel 2 6 56 26 072 12 Watt solid state MIDLAND STEREO AMPLIFIER Model BB 00 26 00 25 Watt Solid State 1 00 2 ELECTROLYTIC CONDENSERS 40 Mfd 300V 40 Mfd 400 50 ASSORTED FUSES Popular asstad ampere ratings 50 RADIO amp TV SOCKETS ull 1 ype 7 pin amp pin 9 pin ete 1 5 7 UNIVERSAL SPEAKER 10 20 40 OHM Imped 95 eramic Mag ve s2 TELEMATIC TUNER MATE KT 730 Portable Subst i uner 333 95 TELMATIC TEST JIG odel F J 190 light packing for safe delivery at minimum cost euneaneese CASSETTE C 120 FREE GIFT WITH EVERY ORDER MYLAR RECORDING TAPE CASSETTE C80 CASSETTE C 90 ae 8 Track 64 Min 1 29 a 8 Track 80 Min 1 59 ee es 8 Track Cleaner 1 49 wes 3 TAPE REEL 07 maple 3 TAPE REEL 09 ed 5 TAPE REEL 19 ae 7 TAPE REEL 24 MATCHED PAIRS TRANSISTORS NPN amp PNP 12N4252 2ON2OS CUN222U ONDODTI i Rash set KNOB SPECIAL 100
165. l 550 Prec Voltage Regulator DIP 95 ea MM 5314 24 pin LFD Incandescent readout 555 Timer MINI DIP 1 25 ea digit with spec sheet 10 95 ea 703 RF IF Amp MINI DIP 59 ea 709 Operational AMPL TO 5 or DIP 45 ea MM 5316 40 pin norm alarm set snooze alarm timer 741 Dual Different Compar DIP 39 ea 12 or 24 hr operat with spec sheet 15 95 ea 723 Voltage Regulator DIP ea 739 Dual Hi Perf Op AMP DIP 1 25 ea 741 Comp Op AMP MINI DIP TO 5 45 ea 747 Dua 741 Op Amp TO 5 or DIP 95 ea MVIOB Visible red TO 18 25 ea 748 Freq Adj 741 MINI DIP A5ea MVSO Axial leads micromin dome 25ea 5 1 00 1303 Stereo Pre Amp DIP 95 ea MV5020 fumbo clear dome visible red 35ea 3 1 00 1304 FM Mulpx Stereo Demod DIP 1 50 ea ME4 Infra red invisible ditf dome 60 ea 1307 FM Mulpx Stereo Demod DIP 95 ea 1458 Dual Com Op Amp MINI DIP 75 ea a LH2111 Dual LM 211 Volt Comp DIP 2 95 ea DISPLAYS d 3065 TV FM Sound System DIP 75 ea j 3075 Fat Det LMTR amp Audio 560 Phase tocked Loop DIP 2 95 ea Pre Amp DIP B5 ea 561 Phase Locked Loop DIP 2 95 ea care Ss eer na pe r 1 Fit 362 Phase Locked Loop DIP 2 95 ea 7524 Core Mem Sense AMPL DIP 195 ea 565 Phase Locked Loop DIP 2 95 ea 7525 Core Mem Sense AMPL DIP 95 ea 566 Function Generator MINI DIP 2 95 ea 7534 Core Mem Sense Amp DIP 2 75 ea 567 Tone Generator MINI DIP 7535 Core Mem Sense Amp DIP 1 25 ea S 2 95 a 8038 Function Generator DIP 8 95 ea OP TO ISOLATORS 9601 Retriggerable One Shot DIP 95 ea m 75
166. l client tells you that his 200 turntable or 00 tape deck sounds funny Wow and flutter are symptoms of mechanical troubles in tape and record player mechanisms that can make the players sound real sick You need specialized equipment to test tape and re cord player mechanisms and to keep acheck on the effectiveness of your servicing pro cedures Both of these troubles are variations in the tape or record speed that frequency modulate the recorded and or recording signal The rate of variation determines whether it iswow orflutter When the record ing or playback speed varies at a rate of 0 5 to2 Hz we have wow Flutter is heard when the speed varies at arate of 2 Hz and higher When speed changes at 2 to 6 Hz even the most unmusical ear can detect the periodic changes in pitch At 6 to 10 Hz notes begin to sound as though vibrato is being used At higher variation rates the signal may sound garbled or harsh Wow and flutter are measured using a test tape or record with a3 kH7z test tone played on the equipment under test The wow flutter meter see block diagram of a typical instrument in Fig 8 is connected across the output of an amplifier fed by the player An input attenuator sets the signal to the desired level A following limiter stage clamps the signal level so readings are not affected by amplitude variations The signal goes through a bandpass filter and harmonic suppressor and on to a 3000 Hz rejection filter a
167. l color eighty page book on careers in advanced electronics In it you will find full facts on the exciting kinds of work which CREI pro grams open up to you And full facts on the compre hensive courses of instruction the strong personal help and the professional laboratory equipment which CRE makes available to you All at a surprisingly low tuition cost And when you have it talk with your employer about it Tell him you re considering enrolling with CREI He ll undoubtedly be happy to know you are planning to increase your value to him And he may offer to pay all or part of your tuition cost Hundreds of employers and government agencies do Large and small Including some of the giants in electronics f they are willing to pay for CREI training for their employees you know it must be good Send for Advanced Electronics today You ll be glad you did om CAPITOL R O INSTITUTE WASHINGTON D C 20016 Veterans and servicemen check here for G Bill information O RADI a ENGINEERING Super Values RAYTHEON TUBES 5 6BAl1 4 75 5 6GH8 3 55 5 12GE5 4 75 SSE sas es Z00 5 3KT6 ecua 4 25 5 4BU8 5 00 5 35EH5 3 85 CARTRIDGES BULK SONOTONE 8 T 22 45 cescaseess 1 25 Ea BSR ICES Aa a oyeeeee 1 25 Ea VARCO CN 72 oo eh 1 25 Ea YOKES B W Y 130 Zenith 95 2874 7 95 Ea Y 105 MANY CHASSIS 7 95 Ea Motorola 24D66926A04D
168. l have to be made in the future Heathkit GR 2000 is tomor row s color TV today Why not see what the experts have seen The Heathkit Digital Design Color TV without question the most remarkable TV available today Mail order price for chassis and tube 659 95 Remote Control 89 95 mail order Clock 29 95 mail order Cabinets start at 139 95 Retail prices slightly higher Send for your FREE 74 Heathkit Catalog world s largest selection of electronic kits HEATHKIT ELECTRONIC CENTERS Units of Schlumberger Products Corporation Retail prices slightly higher ARIZ Phoenix CALIF Anaheim El Cerrito Los Angeles Pomona Redwood City San Diego La Mesa Woodland Hills COLO Denver CONN Hartford Avon FLA Miami Hialeah Tampa GA Atlanta ILL Chicago Downers Grove IND Indianapolis KANSAS Kansas City Mission KY Louisville LA New Orleans Kenner MD Balti more Rockville MASS Boston Wellesley MICH De troit MINN Minneapolis Hopkins MO St Louis NEB Omaha N J Fair Lawn N Y Buffalo Amherst New York City Jericho L L Rochester White Plains OHIO Cincinnati Woodlawn Cleveland Columbus PA Phila delphia Pittsburgh R L Providence Warwick TEXAS Dallas Houston WASH Seattle WIS Milwaukee Circle 100 reader service card HEATH COMPANY Dept 20 7 Benton Harbor Michigan 49022 Please send FREE Heathkit Catalog
169. l hi fi enthusiasts who prefer a fully manual turntable the rational being that the fewer the number of moving parts the less likely the possibility of ex traneous wow and flutter A perfect exam ple of the high level of performance to be found as the number of rotating components is reduced ts to be found in the Technics SL 1200 turntable which has but one moving part the platter In fact though Panasonic touts their Technics SL 1200 as a Direct Drive Turn table itis a complete Manual record player consisting of the direct drive platter high performance pickup arm acoustic resistant mounting feet and integral dust cover But since the direct drive platter is the most im portant we ll cover that item first The drive motor is a de servo type with the platter attached directly to the shaft Electronic speed control determines and holds to precision tolerances the user selected 33 rpm or 45 rpm speed Attached to the rotor is a control rotor actually a toothed metal wheel Positioned around the control rotor are three pairs of coils one coil of each pair is driven from an oscillator of approximately 50 kHz As the rotor turns it determines the degree of coupling between each pair of coils hence the amount of signal induced in each secondary coil The output from the secondary coils is rectified and used to control three power transistors which feed current through the motor wind ings Three speed control coils wound on the m
170. lastic block is used only for spacing on the male connector Some new keyboards are available from Dan Mayer at Southwest Technical Pro ducts Price with encoder is 39 95 DON LANCASTER I M FOR MEN Your not so subtle change in the masthead of Radio Electronics has not gone unnoticed The magazine to which subscribed FOR MEN WITH IDEAS IN ELECTRONICS has apparently gone the way of all flesh It too has decided to abandon all of its integrity and join the massive Sea of Capitulation in which the rest of our society is immersed Perhaps there is some significance in my observation that the very month after we e Tests Predetermined Frequencies 25 to 1000 MHz e Extended Range Covers 950 MHz Band zoa Bp e Pin Diode Attenuator for Full Range Coverage as Signal Generator we z e Measures FM Deviation MOBILE s Ea 7 Tii qa aa WRITE FOR CATALOG 16 Circle amp on reader service card FM 2400CH meter only 595 00 RF crystals with temper ature correction RF crystals less temper ature correction 24 00 ea 18 00 ea IF crystals na te catalog price INTERNATIONAL E k CRYSTAL MEG CO INC 10 NO LEE OKLA CITY OKLA 73102 your masthead change you featured an article aptly titled Here Comes the FEM To What hope that the mailing list that you got from MS magazine was worth the effort Old magazines like old soldiers
171. le These two lines are found above the B output lines and below the A output lines on the printed circuit board These strobe lines provide us with the Keypressed signal required to enter data into the TV Typewriter A monostable is attached to this strobe line to stretch the pulse width and the 10 uF capacitor used for debouncing is removed from the TV Typewriter This is C17 Shown in Fig 8 of the TV Typewriter booklet HOOKUP THE MARK 8 COMPUTER TO YOUR TV TYPEWRITER using the circuits shown above and to the left Wiring to the TV typewriter is just direct connections above The IC monostable left stretches the pulse width Together the TV Typewriter Radio Electronics September 1973 and the Mark 8 make a powerful computer package This is the second time that Radio Electronics has presented aconstruction article in the fashion We are doing so only because of the special nature of this story and to make it possible for interested readers to get full details on the computer in a single package These details include full size printed circuit patterns and parts layout overlays We do not intend to do an article this way as a regular practice All conventional construction articles will be published complete within the regular pages of Radio Electronics Editor Data in the A register is output to the TV Typewriter as a complete ASCII Character The computer then enters a cation indicated by that address Output 000 port 0 is a
172. le which requires comparable uhf tuning in all sets manufactured on or after July 1 Comparable tuning means detent or preset uhf making uhf as simple to tune as vhf Since most hybrid set designs contain continuous uhf tuners some manufactur ers have decided that July will be the perfect time for the Changeover Rather than re tool for new hybrid models with the currently required tuners they ve decided to go with the wave of the future and build only solid state sets You ll continue to see plenty of hybrids and continuous uhf tuning sets in the market place for some time Manufac turers have been stockpiling so they won t be caught with out low priced sets to sell dur ing the intensely competitive fall season But finally tube type sets seem to be in the last gasp stage Sera e Videoplayer census Enea area There were 118 500 car tridge and cassette video players and recorders in use in the United States as of Jan 1 1974 according to Creative strategies Inc a research or ganization which forecasts the number of units in use will double this year Of the 118 500 units 68 700 are record and play devices and 49 800 are designed for playback only More than half of the machines 65 000 are the Sony U Matic helical scan 33 inch VTR type The second most popular type is the Philips half inch helical scan with 27 500 in use e Long long scan REAS i ee The first developmental vid
173. lete 14 bit address since the memory does the complete decoding Each of the addressed memory locations may store one 8 bit word or byte of informa tion For 2 or 3 byte program steps two or three successive memory locations are used for storage The 1101 type memories are volatile semiconductor memories and information stored in them will be altered or lost if the power is shut off If you want to save a program leave the power on A chart in the construction section shows how the memory jumpers are wired for each of the four possible boards Boards must be added in numerical sequence 2 3 and 4 Blocks of memory must be added in units of 256 words in the A B C and D sequence to prevent gaps in the memory A read write or R W line is provided on the module so that data may either be read from or written into a selected memory lo cation The CPU and the Manual Control module both control this line so that data may be entered under computer control or 31 ow Bt so that we may insert our program data into the memory prior to use by the computer The eight data output lines from the memory are sent to the CPU I O bus through the Input Multiplexer module When we ask for data from the memory with an LrM type of instruction see Intel User s Manual the CPU senses that the memory data is needed and it sets the input multi plexer so that the data is placed on the 1 0 bus at the proper time The Output Latch module i
174. lifier Q102 Q103 and Q104 described earlier is direct cou pled via voltage divider resistors R201 VR205 and R230 to the base of Q213 across base resistor R231 3 3 K VR206 is used to set perfect de zero voltage or a balanced condition bet ween the differential amplifier pair Q213 and Q214 When the dc voltage at the ratio de tector output is close enough to zero actually within about 10 mV so that the set is considered to be in tune the voltage across both R232 and R233 is less than the Vne of either Q215 or Q216 Under these circumstances neither Q215 or Q216 conducts sig nificantly and the voltage across R237 is near zero If the receiver is detuned so that either a positive or negative voltage exceeding 10 mV appears at the ratio detector output point the voltage across R232 or R233 exceeds the V of Q215 and Q216 and one or the other of these transistors conducts heavily into saturation causing a potential to develop across R237 Note that Q217 ts hooked up not as a transistor but rather as a diode In fact it exhibits the characteristics of a Zener diode but has a non critical breakdown voltage of anywhere from 4 to 9 volts dc When breakdown voltage is reached that voltage is applied to the base of Q218 which then conducts heavily reducing the voltage at the col lector of Q218 which then conducts heavily reducing the voltage at the col lector of Q218 and at the base of Q219 219 is therefo
175. lloscopes Signal Generators Semiconductor Testers Power Supplies Probes Tube Testers and Substitution Boxes Circle 4 on reader service card Lg TS AN R amp 4 f upu 4 computer is a cor er which may be edina of purposes including t tion data manipula of wee oe a ob to send cata toa l to a terminal BET Electronics 1 Vv vp SE NINE Bn tember 1973 MARK 8 MINICOM ITER faces wna de ad ve r a aR 2A 4 w Kr re ae de y Input code e self c can convert th ne equivalent ASCII code for outpu t gi This Minicomputer is not a glorifie A i calculator and it is not intended met TRT tan a for educational use It can be inter faced to a calculator a possible fu ture projecit if readers are in terested tp perform complex sal routines and it may also be TED a te j d e CONTRO akg tep GET THE COMPLETE STORY The Minicomputer is a very special story Complete instruction information including full size circuit board patterns would require a long multi part article in Radio Electronics To make it possible for interested readers to get full details of the unit and to start construction immediately we are making available a special package of additional data This includes complete construction details more data on how it works a group of eight experiments you can perform with the computer and other
176. loscope Only minor changes re quired No electronic experience necessary ll lustrated plans 2 00 SANDERS Dept A 25 Box 92102 Houston Texas 77010 CALCULATOR KIT Kit Contains NORTEC calculator chip 4024 21 driver transistors 8 LED s 7 segment readout by EXITON 3 LED for overflow low btry over range a keyboard by FLEX KEY All this 45 value for only 16 50 2 for 27 BASIC CLOCK KIT We furnish clock chip CT 7001 and 4 first line LED readouts 3 inch hgt You furnish the misc minor parts A 35 value for 19 95 LIQUID CRYSTAL WATCH Build a wrist watch or desk clock with this liquid crystal display Recently written up in several magazines Dis play with special socket reads hours and minutes 15 2 for 25 UNDERWATER LISTENING Brand new by OLIN Use it fora swim pool monitor alarm use it on lake or ocean listening to underwater noises fish etc Complete with hydrophone 50 ft mike cable speaker amplifier console Operates from 115 volts AC or 15 volt dry cells 12 Ibs 25 First 3 items airmail postpaid Last item plus shipping MESHNA PO Box 62 E LYNN MASS 01904 Circle S2 on reader service card NEW invention dynamic transistor tester Simulation principle identifies whether un known transistor is silicon or germanium VHF HF or LF npn or pnp Out and in circuit good bad test Kit 32 00 wired 39 50 information 20c SUJITRON 145a Church Street Toronto M5B1Y4 C
177. lso located on the Readout module and it may be used in programming to give a 001 visual output of a byte of data Each of the output registers is represented by eight 002 LED indicators 1 ON 0 OFF As the data held in each register changes so do the 003 indicators Data to be displayed at output port 0 must be sent with an OUT instruction 004 0 010 OO1 or 121s Since the HI address latch is used for 005 some control functions and the LO address latch may also be used for temporary stor 040 age of data going to the output ports at var lous times in programs the data in these reg 041 isters will change from a memory address to these control and output data and then back 042 to an address Checking this data visually in these registers during the debugging of a 043 program is very helpful The power supply requirements of the 044 Mark 8 are 5 Vde at 3 amps and 9 Vdc at 1 5 amps Since regulation at these high cur rent levels is critical we suggest that the 045 power supply or supplies are purchased There are many good power supplies on the 046 surplus market that may be used with the Mark 8 The type used with the prototype is 047 listed in the complete parts List A substi tute available from Wortek 5971 Reseda 050 Blvd Tarzana Calif 91356 will work as well Order part numbers PRS I and PRS 3 each 25 00 R E 051 For more detailed data on the Microprocessor IC write to Intel Corp 3065 Bowers Ave Santa 052 Clar
178. m dispersion at all frequencies Has room filling quality of omni or multi directional system with no beaming of high fre quencies Includes a 10 inch acoustic suspension woofer three 12 inch mid range hemispherical dome radiators and three inch hemispherical dome tweeters Cabinet is of solid oiled walnut 400 00 Acoustic Research Inc 10 Ameri can Drive Norwood Mass 02062 Circle 34 on reader service card CASSETTE DECK model GXC 75D has built in Dolby automatic distortion reduction system three way electrical reverse mode selector and automatic and manual reverse recording and playback Also features lifetime glass and crystal head Has pause control button for tape editing control suspends tape travel at any time during record or playback individual back lighted meter panel indicates various operating modes Reverse mode selector provides one way re cording or playback one cycle forward and re verse recording or playback or continuous playback Other features include tape selector circuit for CrQz2 tape over level Suppressor circuit index counter with memory wind supplement that stops tape at any desired point automatic 78 stop large slanted VU meters and hysteresis motor 5 74 x 18 x 11 in 17 6 Ibs 429 95 Akai America Ltd 2139 East Del Amo Bivd Compton Calif 90220 Circle 48 on reader service card IN DASH CASSETTE PLAYER mode C984 AM FM stereo in dash radio with built in
179. matter how light or or the month and the day dark the room Operation is totally silent with accuracy to within seconds a month life expectancy is an incredible 100 000 hours CHOICE OF DISPLAY MODES You can decide to display time only date only or a continuous 10 second cycle in which time alternates with date You can operate ona 12 hour or 24 hour international time sequence And you can change all display modes instantly any time you wish by flicking simple controls BEAUTIFUL AND BEAUTIFULLY EASY TO ASSEMBLE The contemporary hand rubbed oiled walnut cabinet is ideal for home office or place of business And a very memorable gift All com ponents of the kit mount on two interlocking printed circuit boards for easy assembly in one evening using only a soldering iron and a pair of diagonal cutters The only wire in the kit is the line cord Accuracy is assured by one MOS LS integrated circuit chip and top quality electronic components throughout The Digital clock and calendar s also available factory assembled ORDER NOW FOR IMMEDIATE DELIVERY Send this coupon with your check or money order for fast delivery anywhere in the worid Money back guarantee if not fully satisfied digital concepts Digital Concepts 249 Route 46 Saddle Brook New Jersey 07662 201 845 7101 Enclosed please find my check or money order for or Charge my Mastercharge account number expiration date to cover the
180. ms Telemetering circuits solid state multivibrators and the latest types of integrated circuits are included in your course The NRI color TV and digital computer kits are the latest in a long line of firsts for NRI For more than fifty years NRI has been providing unique 3 dimensional home study training that has helped hundreds of thousands of students reach their goals quickly and easily What NRI provides is a combination of kits and bite size texts that give you hands on experience while you are learning The texts average only 40 pages each and they are fully illustrated You are taken step by step from the first stages into the more advanced theory and techniques with an expert instructor ready at all times to provide valuable guidance and personal attention The level of per sonal attention provided is more than you would receive in many classrooms Once you ve grasped the fundamentals you move with confidence and enthusiasm into new discoveries in the fascinating world of electronics You start out with NRI s exclusive Achievement Kit containing everything you need to get moving fast Lessons have been specifically written so that experiments build upon one another like stepping stones You can perform a hundred experiments build hundreds of circuits as you learn to use the professional test equipment provided building ra dios and TV sets transmitter or computer circuits It s the priceless
181. ms value Thus when measuring IM power levels you must apply a correction factor to the wattmeter reading Use a factor of 1 25 for a two tone test witha ratio of 4 1 determine the correc tion factor hy comparing the peak value of the signal as observed on a scope with the meter reading IM distortion measurements are valid only when the amplifier under test is flat over the range of the two test frequencies so he sure that tone controls are in the FLAT position and that scratch and rumble filters have been switched out of the circuit You can check phonograph cartridges for IM distortion by using one of the special test records made for this purpose as a signal source Poor tracking due to a worn stylus or incorrect stylus alignment can cause a sharp rise in iM distortion as the stylus moves across the record Figure compares the IM distortion from a good stylus and a worn one at different points on the test re cord The ac vtvm A main advantage of an audio voltmeter or ac vivm over the average high impedance multimeter is its added sensitivity response flat within cl dB or hetter over the audio range and a wide range dB scale continued on page 74 22 Ap used for the two channels The channeis can be used together or separately Fullscaie voitages are 100 pV to 300 V in twelve steps Decibel ranges are 80 to 52 when 0 dB 0 775 V and 80 to 50 when 0 dB 1 0 V Input Impedance 10 megohms shunted by 40 p
182. n However this isn t precisely a pure dc circuit The voltage applied to the SCR anode isn t re ally dc but a series of pulses positive going So the SCR turns off every time thts voltage reaches zero which it does 120 times a sec ond The waveform of this is shown in Fig l just above the SCR anode So the SCR will actually turn itself off 120 times per second then be gates back on again for the next half cycle by the voltage from the gate voltage divider Current will keep flowing into the battery as long as the gate circuit is working Three resistors are connected across the output They actually read the dc battery voltage As the battery charges this goes more positive The current through the sens ing resistors also increases as Mr Ohm said Now we come to the secret notice that one of these resistors isn t a fixed type but a thermistor This is a special type of resistor When the current flowing through it increases its resistance decreases This change is actually caused by the resistance element heating up That s why the term therm i1stor Now then when we begin the charge the battery voltage is comparatively low The dc voltage drop across the sensing resistors is such that the gate of the SCR stays posi tive with respect to its cathode enough to make sure that the SCR stays on When the battery gets to full charge the dc voltage rises So the current through the sensing re sistors rises with
183. n base solderable 7442 Left hand decimal point 7446 COMPLETE W DATA 14 95 DATA ONLY Re 7447 fundable with purchase of chip 1 00 7 SEGMENT READOUT 1 PIN OIP CLASSIFIED COMMERCIAL RATE for firms or individuals offering commercial products or ser vices 1 15 per word minimum 10 words NONCOMMERCIAL RATE for individuals who want to buy or sell personal items 70c per word no minimum FIRST WORD AND NAME setin bold caps at no extra charge Additional bold face at 10c per word Payment must accompany all ads except those placed by accredited advertising agencies 10 discount on 12 consecutive insertions if paid in advance Misleading or objectionable ads not accepted Copy to be in our hands on the 26th of the third month preceding the date of the issue i e August issue closes May 26 When normal closing date falls on Saturday Sunday or a holiday issue 7450 closes on preceding working day PLANS amp KITS ELECTRONIC organ kits keyboards and many components Independent and divider tone generators All diode keying IC circuitry Sup plement your Artisan Organ 35c for catalog DEVTRONIX ORGAN PRODUCTS Dept B 5872 Amapola Dr San Jose Calif 95129 FREE catalog Most unusual electronic kits available Music accessories surf wind synthe sizers wind chimes many others PAIA Electronics Box B14359 Oklahoma City OK 73114 CONVERT any television to sensitive big screen oscil
184. n is on Ideal for semiconductors delicate components that could be damaged by heat Many replaceable tips in various shapes sizes 20 70 Power Microscope Pocket size 20 to 70 power scope gives you a close up view of circuitry components tiny metal or plastic parts the surfaces of mirrors metals glass wherever you are in the field in the lab at the work bench in the home Comes with tripod legs pen light zipper case rig todoy for Electronic Tools amp Test Instruments Mehl Ear ETRE Whe HUTS CALIF THOI Circle 64 on reader service card circuits WINDSHIELD WIPER PAUSE CONTROL A number of windshield wiper pause controls have been described in the press Most consisted of a two or three transistor circuit with numerous associated Components Here is the diagram of a design that is simpler and less expensive than most It uses the low cost and versatile NESSS C by Signetics as a free running oscillator with its frequency adjustable from one cycle every three seconds to one cycle every 30 seconds R2 R3 75K 500K D1 GO0PIV 1A DIODE Rl and C set the width of the negative going pulse and thus the period of time that power is applied to the wiper motor The positive going pulse width ts adjustable independent of the negative going pulse by the com bination of RI R2 R3 and C1 This is the interval between active cycles The NESSS drives the relay directly and can ha
185. n the Readout module Six different modules The Central Processor Unit CPL module contains the microprocessor IC and the extra circuitry used to interface with the rest of the computer It is important to note that the 8008 microprocessor has been fabricated as an MOS circuit and the outputs will only drive one low power circuit of the 741 series Each output ts buffered with a 741 04 inverter before it is used The main X line input output bus or 1 O bus is also buffered by two 7404 circuits to give the TTL signals a high fan out The computer is controlled by a 2 phase clock supplied by a crystal oscillator which controls the pulse widths and frequency The clock and the synchronization signal supplied by the microprocessor are used to control some of the logical operations of the computer interface circuits The synchroni zation signal synchronizes the operation of the very fast TTI circuits and the slower clocked MOS circuits in the microproces sor The microprocessor also has three state output signals S Si and S which are used to drive a decoder The eight possible states are then used to control other func tions in the interface logic A complete de scription of the generation and use of these State outputs ts included in the Intel Liser s Manual Since the CPU uses a parallel amp bit 1 0 bus for input and output of data there must be some control of when the bus is sending data from the CPU to an external
186. nd FM discriminator so all frequency components other than the 3000 Hz can be read on the built in vtvm There ts an adjustable bandpass filter at the discriminator output When the filter ts set to 0 5 to 250 Hz the reads the sum of both wow and flutter Setting the mode switch to FLUTTER cuts in a sharp filter that removes all frequencies below 6 Hz In the ADJUSTABLE BANDPASS FILTER 0 5 250Hz 0 5 6Hz 6 250Hz TECTOR FIG 5 BLOCK DIAGRAM OF WOW AND FLUTTER meter for testing turntables and tape recorders justed up or down as necessary to keep the amplifier s output voltage constant The amplifier s gain is up or down at that frequency is above or below the gain at the reference frequency by the change re quired in the attenuator setting in dB The meter across the amplifier output cannot be used except as areference meter when making precise gain or response measurements The small changes in output voltage level are difficult to read and even harder for many to convert to gain or loss in dB For example assume that the am wow position of the mode switch the filter removes all frequencies above 6 Hz so the meter measures Only the wow component Most wow flutter meters have a built in 3 kHz oscillator so you can make a test tape when necessary Some include facilities for measuring turntable rumble Others also measure driff slow speed variations but more often defined as long term speed varia
187. nd a minimum number of package pins How can we do all this at once Several keyboard systems we could use are in Fig 4 Figure 4 a show s about the worst we could do Here we have one common lead and one output lead for each individual key If we had 16 keys this would take 17 leads We can cut down on the number of leads with a diode encoding network as in Fig 4 b by encoding l of 16 to 1 2 4 8 4 line binary This takes a bunch of diodes but saves us on package pins In a system of this type we might make a 0 the equivalent of a binary 10 or 1010 This way our 0000 State can be a do nothing state and any other combination indicates a key pressed command Thus binary through 10 would be the numbers and binary 11 through 15 would be the add subtract multiply divide and equals commands We can go to the keyboard matrix of Fig 4 c to eliminate the diodes Here we arrange our keys in a 4 x 4 array There are four lines from the calculator that source current there are four lines to the calculator that sink current Press any one key and one of the source lines gets shorted to one of the sink lines There are 16 possi ble combinations of source to sink shorts that may be uniquely internally recognized as a numeral or a machine command This eliminates the diodes but we still need 8 input leads Can we do any better Remember that we already have 8 10 or 12 digit driver lines going to our multiplexed display If we use
188. ndle up to 100 mA thus making it possible to use almost any inexpensive 2 volt de relay The total cost for parts is under 5 00 ames Batongardt LINE OPERATE YOUR LED S Light emitting diodes LED s have become quite the in thing as indi cators because of their low current drain and indefinite life However it seems that when ever I F1 s are used in a circuit they are associated with a dc power supply of some sort But haven t there been times when you would have liked to run them directly off the ac line Well you now can and continued on page 55 Continental Specialities Corp 325 East St Box 1942 s New Haven CT 06509 am LEN ig k I a mi N ia ee a h LA ei as F i i i ar E E at U So ot ie i i ui ny a E eo bs ial ha al gn tee ek a s m B Pa Ta a a iaa imi i i a hi a ih i ao kn g 5 be E 4 gag ie oe i kaar P hoia i ha a i i i ri i A ji L i F nue e n Baa a h a ve ee a ae a eal ss ae oll Sareea NN eos NAN en Nae ean ta SEE THUNK It 1N Aaaa siti dies ne Lh A S tea RES i Aa HS a Ma z TA ANNAN RN har i CANTIK Y m qee NSN M r WOLYWVs SOs F tt IR Squeak y ne ARRS NY X NS A h ry Whirr Pss silence RRA Gute those mo CV parts witt squirt from ing handy spray pack Cleaned away dirt dust and crud Without dam 23 1 E acCH sanything in any LUBRI CLEANER black and white or YOU
189. nds on the voltage of the charger and its current rating This can be up to to 2 amperes It doesn t do any useful work since the bat tery 1s already up to full charge What it does is generate heat This makes the water evaporate out of the electrolyte and it also liberates gases which can be dangerous Oxygen plus hydrogen plus small spark makes one heck of a bang So the newer chargers are provided witha voltage sensing circuit This turns the charger off when the battery reaches full charge The signal for this is the voltage across the battery Before it reaches full charge this will be lower than normal when it is fully charged it will rise In a standard 2 volt battery somewhere between 13 and 14 volts This automatic protection is provided by an SCR in a novel circuit see Fig i As 0 POLARITY LAMP you can see the transformer and rectifiers are still there The positive terminal of the dc output center tap of the transformer is connected to the anode of the SCR The negative terminal of the dc output is the common anodes of the rectifiers So now the charging current flows through the SCR An SCR will not conduct current at all until it is gated on by applying a small positive voltage to its gate Once it is turned on however it keeps on conducting until the anode voltage drops to zero If we look at this as a dc circuit the SCR would con duct at all times once turned o
190. never die they just fade away So let it be with my subscription With fond memories JOSEF SCHOENBRUN Santa Monica Calif Reader Shoenbrun s letter was dated April 7 We ve taken it in the spirit of that day In case he was serious hail and farewell ex reader Shoenbrun For the record fet it be said that the change on the masthead from For Men With Ideas In Electronics to The Magazine For New Ideas In Elec tronics was made because we believe that the slogan should tell what the magazine s contentis rather than whatwe hope it s readers are Editor SIMPLIFIED CLOCK CIRCUIT In the September 1973 issue a simple digital clock circuit was shown p 66 by Mr Glover This circuit can further be sim plified Mr Glover did not use a 7490 IC in the hours counting section because of the particular reset function count 1 12 reset to 1 desired A 7490 may be used but instead of ex ternally connecting it in the normal BCD fashion the two sections count by 2 count by 5 are used separately A sepa rate 7473 drives the A input of the 7447 while the onboard count by 2 section of the 7490 drives the tens of hours display The advantage of this method is evident upon examination of the reset characteris tics A Single 2 input AND gate is required to complete the reset function and this can simply be substituted for by two diodes The transistor is any bargain pack general purpose device The second half
191. nly METRIC e 101 10 5 8 x4 5 29 95 TO ee 102 12 7 0 x4 5 39 95 ENGLISH je 103 24 9 0 x6 0 59 95 SLIDE i 104 32 9 5 x8 0 79 95 he x RULE fiz Order today or send for free selection guide with applications photos specs and more Convert lengths arsa a ju Weight volume Z instantly e kig Yours FREE jati la JA with each i et Proto Board Order wg 7a etal Telephone 203 624 3103 CANADA Avallable thru Len Finkler Ltd Downsview Ontario Circle 67 on reader service card 87 5 r yY with just two additional parts Get a silicon diode of 4 amp 200 PIV or better and a ITOK l watt resistor Connect them as shown to your LED and vou are all set If vou IN2069 OR EQUAL AL 276 042 RADIO SHACK use a larger LED than the one specified a new budget priced unit from Radio Shack and you want a little more COLLECTORS We ve just added the 1927 Radio Encyclopedia to your growing library S GERNSBACK S 1927 RADIO ENCYCLOPEDIA is your technical book on wireless and early radio Deluxe illustrated reprint of the original 175 pages 12 95 hard cover_ 9 95 soft cover_ VINTAGE RADIO is the fascinating photo refer ence far collectors and historians 1887 1929 263 pages over 1 000 photos 6 95 hard cover 4 95 soft cover RADIO COLLECTOR S GUIDE is the data book for collectors 50 000 facts 1921 1932 264 pages 3 95 soft cover And now while
192. nna in prime signal areas Inbuilt monitor loudspeaker with separate level control Video carrier level meter may be calibrated against Master Gain Control for the area in which the instrument is used to afford true field strength measurements Lightweight and measures a mere 6 5 x 6 5 x 3 25 exclusive of knobs handle and antenna Complete with connecting cables and instructions You get all this for 169 95 at your stocking distributor _ or write for more details and complete specifications CASTLE TY TUNER SERVICE ING 5715 N Western Ave Chicago Illinois 60645 e Phone 312 561 6354 In Canada Len Finkler Ltd Ontario Circle 78 on reader service card Bo m ME TOTS adio ciectronics ho een VIDEOTAPE VIDEODISC BUILD THIS GUITAR PREAMP Doin Wha Get Unique Sound Effects 10S Doing What tre y ot Lape E prm epe FED E FFE P mii pi f ar _ see si eh a talk Peeper pie FLE r pep enue S Eers a e
193. non linear control element The out put of the equalizer is series connected to a gain compensator control amplifier and then to the recording amplifier When the gain compensator control amplifier senses a high level signal it causes the control ele ment to bypass the signal around the equalizer delivering a flat input signal to the record amplifier As the input signal level decreases the control element in creases the amount of signal passed through the equalizer at 40 dB below the reference signal level full high frequency boost Is ap plied to the input signal The actual amount of boost is shown in Fig 1 Note that at 0 dB or reference record level there is virtu ally no high frequency boost At 40 dB there is 10 dB boost applied between 5 kHz and 20 kHz In the playback mode the same high frequency boost equalizer is still used but The overal dimensions of the SL 1200 are 7 3 32 H x 169 32 W yx 13 29 32 D Weight including the dust cover Is 22 1 Ibs Admittedly the overall size and price 279 95 of the SL 1200 is large but the overall performance matches the size and price When a real heavyweight in turntable performance is needed the Technics St 1200 will certainly fill that need R E the contro element is now used in a nega tive feedback amplifier so the system has a reverse characteristic to the recording sys tem The higher frequencies are now at tenuated in the same proportion to the
194. nsumer elec tronic products Compact portable Fully transistorized and weighing i only 15 pounds the D61 occu pies only 6 3 inches of bench width It s easy to transport and use In confined working areas Tektronix reliability TELEQUIPMENT products carry the well known Tektronix warranty and are marketed and supported by the Tektronix organization Automatic triggering TV Frame and line triggering Dual trace X Y and vector modes Send me the D61 Spec Sheet and Telequipment gt catalog i 0 Have your field engineer cali t gt arrange a demonstration Tektronix Inc P O Box 500 Beaverten Oregon 97005 Name _ 7 ee hes Title z Telephone Wo _ Company Ue een Address TEKTRONIX PeF committed to technical excellence Circle 85 on reader service card 7 NOW you can train at home building a NEW 25 son Solid State Color TV engineered by NRI for learning and trouble shooti ng So much better for learning TV servicing than any hobby kit because NRI designed and created it as an educational tool Unlike hobby kits which are designed for creating a TV set as the end product NRI built its exclusive 25 Diagonal Solid State Color TV kit as a real training kit You can introduce and correct defects for trouble shooting and hands on experience in Handsome woodgrain cabinet circuitry and servicing The kits include a wide at no extra cost band oscilloscope color bar c
195. nswer one for arithmetic and an optional one NUMBERS SEGMENT STORED OUTPUTS HERE TO TEMPORARY DISPLAY STORAGE BCD 7 SEG DECODER ANSWER KEYBOARD SHIFT OPERATIONS DONE HERE ARITHMETIC ae CONSTANT ARITHMETIC UNIT MEMORY STACK FROM KEYBOARD HOUSEKEEPING amp MICROPROGRAM TIMING SEQUENCE ALGORITHMS FOR X AND STORED HERE PERMANANT STORAGE FIG 5 tNSIDE THE CALCULATOR IC The keyboard section reads and sorts out input signals from the keyboard DIGIT OUTPUTS TO DISPLAY oan ENTER SHIFT REGISTER ada 1 fe RECIRCULATE Orrin 4 IN A Qi IN a EACH VERTICAL GROUP OF FOUR BITS REPRESENTS ONE DIGIT FIG 6 TYPICAL MEMORY in memory stack Length of shift register depends on number of numerals and sign digits to be shown equ il bee IN pm N CIRCUIT TRANSISTOR TESTER ment quippe ga HIGH FIDELITY AAE SPEAKERS SOLIE STATE STEREO E AM FM RECEIVER aad ee LO SILHO SUPERHET RAC O eat peon apon SIGNAL TRACER 5 OSCILLOSCOPE Choose from 12 NTS Electronics Courses includ ing Color TV and B amp W TV Servicing Electronics and Computer Technology Electronics Commu nications amp FCC and Industrial amp Automation Electronics All courses can provide you excellent opportunities to expand your career in the exciting world of electronics So
196. nto protection and even then there are no annoying flyback pulse noises or DC fuses to blow The new DC300A has unprecedented Signal purity IM and harmonic distortion ratings are 05 although typically below 025 Hum and noise rating is 110dB be low 150 watts while typically 122dB The difference in increased listening comfort IS Impressive Although totally new the DC300A has inherited some important traits from its predecessor PRICE still under 700 WARRANTY three years on all parts labor and round trip shipping POWER RATING 150 w ch continuous at 8 ohms power at clip point typically 190 w Ch at 8 ohms 340 w ch at 4 ohms 500 w Cch at 2 5 ohms or plug in two parts for 600 watts continuous mono power at 8ohms There are many new super power am plifiers But when you buy a Crown DC300A you re buying more than just an amp You re buying the Crown company a professional audio equipment manufacturer with a 26 year reputation for solid quality and lasting value There are thousands of Crown amps in the field still working to their original specifications and still outperforming most new amps Visit your Crown dealer to hear the difference For detailed product data write Crown International Box 1000 Elk hart Indiana 46514 crown 14 Circle 6 on reader service card ti f TR ew E gt f me VY conimes om page 12 electronics a 64 channel stimulator controlled by a computer It was in tu
197. of 75 dB and better Few station studio consoles provide that kind of signal to noise and hum performance Many tuners and receivers can de code the stereo multiplex composite signal with channel separation exceed ing 40 dB even though the FCC re quires only that stations transmit sep aration of at least 30 dB from 50 Hz to 15 000 Hz Harmonic distortion in modern tuners is down to a fraction of one percent but with most music broadcast over FM coming from rec ords and tapes one seldom is able to take advantage of this low distortion capability since even the best phono cartridges and tape playback machines used at broadcast stations fall short of reproducing the recorded material at such a low level of distortion Small wonder then that recent ef forts in the design of new FM high fidelity components have concentrated more on convenience features These do not directly affect audible performance but do make it easier for the user to take advantage of the superb performance capability built into these products Harman Kardon s new model 900 shown in Fig 1 has two interesting circuits which are worth noting both of which are di rected towards more accurate and bet ter tuning of FM stations The two circuits analyzed here replace the conventional signal strength meter and center of channel meter so common in better quality FM receivers and tuners Although a tuning meter is clearly visible in the front panel p
198. of ARRL National Convention International Friendship through Amateur Radio is the major theme of the National Convention of the American Radio Relay League to be held at the Waldorf Astoria Hotel New York City July 19 through July 21 A secondary theme is Building for the Amateur Radio Operator of Tomorrow As in the many former conventions of the League which has represented the radio amateur since before World War the meeting will feature authoritative pap ers and discussions on ham subjects and also the usual social activities of a ham gathering ISCET starts technical library of electronic information An international Technical Electronic 50 IN TUNE WINDOW m Va218 COLLECTOR 10MV 1OMV lt gt FREQUENCY a RATIO DET DC VOLTS FIG 6 VOLTAGE RELATIONSHIPS at indi vidual points in in tune circuit redundant situation Ideally if the user is equipped with a rotator for his atenna or can send a friend up to the roof to Clearing House TECH is the way lib rarian Henry V Golden CET describes the newest move of the International Soci ety of Certified Electronic Technicians ELECTRONIC TECHNICIANS DISCUSS the electronic clearing house and look over the literature that has arrived at the new library QUIETING METER B VR204 MUTING ADJ O MUTING O TO MPX CIRCUIT a alie B do it the hard way the quie
199. of appliance repair and two shall not at the time of appointment be directly or indirectly identified with the business of electronic equipment or ap pliance repair apparently representatives of the public The bill if enacted into law will take effect January 1 1975 a ae se ee ee ee ee ee ee ee ee e MOVING Don t miss single copy of Radio Elec tronics us Six weeks tice Your old dress and code Your new dress and code please print address city state zip code Mail to Radio Electronics SUBSCRIPTION DEPT BOULDER COLO 80302 Look what comes FREE _ with Sams Photofact ag Easy Buy Plans O In your business the right Photofact Set is almost as essential as the right tools And Sams Easy Buy Time Payment Plan makes it easy to have the right set when you need it Just use the Easy Buy Plan p to start or to fill out your Photofact library sa y and you ll not only save 1 00 a set you ll Getic att also get a bonus of FREE tools or equipment Sey And there s no carrying charge One dollar saved on each Photofact Set bought on time without a carrying charge plus FREE tools Its an offer no TV or radio service shop can afford to pass by Which of these five great Easy Buy Plans best fits your needs Easy Buy Plan 1 Any 60 Photofact Sets you need for 20 down 145 balance payable without carrying charge Plus the 6 15 Xcelite screwd
200. of the 7473 may optionally be used for an AM PM indicator clocked from A out of the 7490 DANIEL GOODELL Concord Calif LIKE ELECTRONIC MUSIC I d like to take the time to compliment you on the recent various articles on elec tronic music synthesizers especially the six consecutive articles explaining various how and whys of the PAIA synthesizer May through October 1973 It was an ideal series for the amateur electronic musicians aS well as the technogist hope to see more articles on the develop ments of new synthesizer concepts as you are doing a fine job of keeping on top of them am a year from graduating with my Bachelors degree in Electronic Engineer ing from DeVry Tech and am planning to design and build an synthesizer for my seminar project Your articles are the greatest Source of references and ideas MICHAEL L MURRAY Chicago Ill DON T MISS IT An experimental see in the dark infrared viewing system for lots of exciting experiments You can build it for 35 Years pave A Ng Take a really bad tuner The contacts are so dirty you have to wiggle the knob to pull in a channel Remove the tuner cover and spray in TUN O POWER Rotate the tuner a couple of times Then stand back and admire the results The tuner contacts are not just clean they re shined to a high luster And they re coated with a long lasting lubricant that makes detent action smooth as silk TUN O POW
201. oltage supply R Y TO COLOR BY DIFFERENCE _ AMPL PLATES G Y t _ _ AAA 270V KINE TO BIAS FLYBACK PULSE BLANKER TO CATHODE OF 2D BAND PASS AMPL FIG 2 Key clue variation of de voltages on picture tube grids and loss of de voltage on blanker cathode This can also be due to an open cathode ribbon in the blanker tube Bianking diodes Diodes have become very popular tor blanking in the later sets Some will use transistors and some a combination of both The advantage of a diode is that it can be hiased so that only the desired part of the blanking pulse passes through For exam ple in many Zeniths you ll find both hori zontal and vertical blanking diodes For the horizontal blanking a pulse trom the flyback is fed through a biased diode Fig 3 shows the circuit The bias keeps the diode cut off until the pulse voltage has risen above the bias level So we get an input pulse as shown with quite a bit of normal ringing along the baseline which is during the scan period The output pulse is clean with the ringing clipped off This is Q1 VIDEO ay TO VIDEO AMPL OUTPUT FROM 1S VIDEO VERTICAL BLANKING HORIZ y BLANK PULSE 220K BLOCKER 235V q lt 4 _ _ TO SECONDARY VERT OUTPUT TRANSFORMER TO FLYBACK 1600 RINGING ANZ INPUT PULSE EGS fed into the emitter of a transistor video am plifier stage If this diode shor
202. ompensate for the intermix dip shown in Fig 3 similarly treble cut for the peak in Fig 4 the results would be at best barely acceptable to the hi fi ser sort of like cutting the highs when playing a Dol byized pre recorded tape on a non Dolby machine Of course how often are tape re cordings intermixed most users stick with FIG 4 tapes made on their own machines and both noise reduction systems work well unto themselves The ANRS is incorporated in JVC s top of the line model C D 1668 which fea tures other unusual and to become inportant features In addition to normal low noise and chromium dioxide bias selection a memory reset counter that al lows rewind to a user determined location and a user removable head cover the CD 1668 has professionally studio calib rated VU meters and an optical controlled cassette eject With very few exceptions cassette recor ders use a 0 VU recording reference which Is already at tape saturation hence since the meter Movement cannot usually follow rapidly changing signal levels such as pro gram peaks the program peaks of the input signal are already well into tape saturation distortion To avoid the peak program dis tortion problems all professional recorders have their VU meters calibrated az least 6 dB below tape saturation what is termed headroom In the CD 1668 cassette deck JVC has not only provided 6 dB head room they have incorporated high speed
203. origi nal signal level as shown in Fig 2 Since the equalizer cannot distinguish between pro gram signal and noise it attenuates both equally as the program is restored to its original Hat response the noises gener ated within the ANRS system loop are at tenuated some 10 dB between 5 KHz and 20 kHz at the lower program signal levels As shown in Figs and 2 the encoding and decoding are not exactly complemen tary as they are for the Dolby system but the variations are so slight as to be meaning less unheard for program material The big question of course is how interchangeable is the ANRS with Dolby What happens when an ANRS decoder is used with a Dolby decoder and vice versa The first considerations are the equaliza tion frequencies Whereas the ANRS pro vides about 5 dB equalization at KHz and 10 dB equalization at 10 KHz the Dolby B the model used in consumer equipment has SdB equalization at about 800 Hz and 10 dB gt YF PHF PHILS IS RA D S SOSO YY kyrt S fF SFHSFr Vr oCvS amp FIG 2 equalization at about 3 kHz Thus Dolby provides the full 10 dB noise reduction 2 kHz below that of the ANRS In terms of listening sound quality though both systems deliver excellent noise reduction the Dolby sounds slightly more quiet or hiss free Because of the differences in equalization depth vs frequency there are variations in frequency response when the systems are intermixed such
204. otion Win your diploma in ENGINEERING MATHEMATICS from the Indiana Home Study Institute We are proud to announce two great new courses in Engineering Mathematics for the electronic industry These unusual courses are the result of many years of study and thought by the President of Indiana Home Study who has personally lectured in the classroom to iko usands of men from all walks of life on mathematics and electrical and electronic engineering You will have to see the lessons to ap preciate them NOW you can master engineering mathematics and actually enjoy doing it WE ARE THIS SURE you sign no contracts you order your lessons on a money back guarantee In plain language if you aren satis fied you don t pay and there are no strings attached Write today for more information and your outline of courses You have nothing to lose and every thing to gain The INDIANA HOME STUDY INSTITUTE Dept RE 774 P O Box 1189 Panama City Fla 32401 Circle 20 on reader service card Assemble this digital clock and calendar in just one evening get continuous readout of hour minute and second plus month and day This new Digital Concepts electronic digital clock and calendar indicates the hours minutes and seconds _or alternates between time and date at 10 second intervals Glowing orange digital readout a continuous character 55 inch high is visible from almost any viewing angle no
205. otor windings generate a three phase equipment ac voltage Whose amplitude is directly prop ortional to the motor speed This voltage is rectified and compared to a reference vol tage determined by the selected 33 rpm or 45 rpm speed If this comparison shows a dif ference between speed and reference vol tages the current flow through the power transistors is automatically adjusted to compensate for the speed variation Since corrections are made with electronic swift Ness speed inaccuracies are corrected be fore they are heard By the same system of voltage compari son fluctuations in the ac line voltage or mechanical loading of the platter are cor rected before they ure heard To compensate for the variations normal to consumer equipment and to provide pitch control for those so inclined to modify a recording two trimmer adjust ments are provided on the top deck one for each speed The trimmer or pitch controls provide a nominal 5 speed adjustment range To insure precise speed setting hy the user the 3 86 Ib platter has strobe markings on the outer rim for both speeds for 50 and 60 Hz line frequency A built in lamp illuminates the strobe The Technics S1 1200 is spee d for a 03 wow and flutter Our measurements indi cated O4 the difference being well within expected instrument tolerances and cer tainly an outstanding value Rumble was ab solutely inaudible Speed regulation was constant o
206. ou to own immediately any of the electronic in struments shown in the table below for just asmall down payment and only four additional easy payments No interest no special charges to worry about Just meet your local participating Distributor s credit criteria Model WO 33B New super portable 3 Oscilloscope 229 00 71 00 Down Model WO 505A DC to 10 MHz 5 Oscilloscope 329 00 101 00 Down Model WV 98C Senior VoltOhmyst 99 95 30 00 Down Model WV 532A Relay protected VOM 99 95 30 00 Down Model WR 514A TV Sweep Chanalyst 380 00 114 00 Down Model WR 538A Super Chro Bar Generator 129 95 39 00 Down Model WT 524A Dynamic Transistor FET Tester 159 00 47 00 Down ALL PRICES SHOWN ARE OPTIONAL WITH DISTRIBUTOR So check off the instruments you need and visit your nearest participating RCA Electronic Instruments Distributor Or write to RCA Electronic Instruments 445 S Fifth St Harrison N J 07029 A distributor will con tact you Hell show you the quick and easy way to own the best in RCA test equipment But hurry This great offer ends on July 31 1974 Model WO 535A Triggered sweep DC to 10 MHz 5 Oscilloscope 349 00 104 00 Down Model WV 510A Master VoltOhmyst 135 00 40 00 Down Model WV S00B Portable Solid State VoltOhmyst 99 95 30 00 Down Model WA 504B 44D Audio Sine Square wave Generator 109 50 36 00 Down Model WR 51
207. ou will find this circuit used in addition to the pulse regulators in quite a few sets Here its main purpose is as a high voltage hold down circuit to meet the HEW regula tions on high voltage supplies If the regulator is working normally and the output tries to rise beyond the range of the regulator the extra pulse amplitude will TO CONVERG CKTS 5 21 5 KV TO CRT Ae 2 R87 6K sw R86 1 MEG FOCUS ADJ i PIN 2 R81 1 5KV V6A 47K R111 270V 1w 33K 5 aP eae gt TUBE W 2 2 8 2 C152 WHT rii 0022 MEG MEG R12 5 5 1 5 a 4 FROM HORIZ C150 ia DISCHARGE 001 o RED x PLATE 1KV R110 2 EF O VDR o gt ORN YOKE 720V 12K C153 FILTERED s 120pF 33K 1KV BOOST BLU FIG 4A VOLTAGE DEPENDENT RESISTOR R110 acts as a rectifler of flyback pulses to develop partial bias for the horizontal output grid This is a hold down circuit 6JK5 FROM FROM OR i pe E 6JH5 HORIZ OSC VOLT REG 7 MEG 100 5 220pF 1 2 TO HORIZ i OUTPUT 5 GRID L 180K 5 27 870V 10uH ra Po 10uH f 470 meg 60N3 or 6Cu3 45pF 3W DAMPER 5KV af FIG 5 HIGH VOLTAGE HOLD DOWN CIRCUIT used in some pulse type high voltage regulators Neon lamps limit the high voltage if the adjustable control shorts be converted into added negative bias on the horizontal output tube Phis will definitely keep the high voltage from exceeding sate limits You ll find VDR s used in the grid bias network
208. ousekeeping functions suchas decimal point circuitry output BCD to 7 segment conversion etc There are two basically different types of memory ina calculator IC The memory stack contains the numbers and changes from time to time as we enter new numbers or as changes are made as a calculation is being carried out This changeable memory is called a read write or Random Access Memory RAM On the other hand the microprogram sequencing information need never be changed for once we teach the calculator how to sequentially perform a cal culation we henceforth and evermore want it to do the same thing So the microprogram is in a fixed data storage mode and is called a read only memory Let s look at the memory stack first Remember that our multiplexed display needs something that goes round and round sequentially putting out digits in the proper order so they can be displayed A memory that does this is called a shift register and the shift register is arranged to normally re circulate its numbers by connecting output to input via a logic circuit Cal culator shift registers usually are dynamic ones they have to be kept moving at all times or the data will be lost Arithmetic is usually done in the 4 bit BCD code This takes four bits per numeral so we really have four separate but identically clocked shift registers to march the numerals around one at atime Such a system is called a parallel by numeral serial by digit arrangement
209. pe PCA 3C 18 Provides 4 Mate pe giana Mas 20 WATT R i tee Unit has controls he used as stereo tune 0 DEP EREL Renee lms 3 BALANCE BASN am PREBLE me sae pC coupled power Mon Oer pre sk Mie debe STEREO for te ature stahilization Each chan las s ite TEMIN Input imp 2 meg for sei e pole AM FM h ie tri i ires iterna l 3 7 oor erystal enrtridges Requires ex 7 ee Se me voltage 18VDC Outputs to 8 ohm Ded aie MULTIPLEX Pea response 40 tz to 30 KHZ Current per ree s s AN Sol Ali Pur The mogt has seo lhe finest omy prices Features huilt in FM antenna record player jacks on separate panel Another external panel consists f provisions for right and left speaker jacks for external FM ground ks far NECN a tape recurd er to tuner or phony of oratenik to record Lower inputs foi Connecting tape deck that will lay back thru the internal ampli Der for systems ineludes red indicta lor on front pane fey STEREO inthe ator Another jack tor plugging in t Pair of stereo he phones Has the foil avin ntralx on front panel PHONO STEREO AM FM MONO FM STE REO TAPE master Control switeds LOUDON SS BAL ANCE TREBLE BASS controls with power ON OFF rocker switch Designer for all aud Philes 10 use as Wall umt in DEN or FAMILY ROOM or central unit by easy gheir in family room or fur those Who wish to de Sign their own con sole or modular system With 6 fe 115 VAC cord and Plug Only 1 x 3M plus el
210. plaining the intricacies of record ing pop music this book fills a gap that has been neglected or overlooked It is of particular value to the re cording engineer since it covers equipment controis and operating techniques currently in use in record ing studios 368 pages softbound No 21037 9 95 METRICS FOR THE MILLIONS by Rufus P Turner Here is an essential reference manual for ail who will be affected by the coming changeover from our present system of measuring to the metric sys tem Each of the various metric units is covered and examples show how to convert from U S to metric and from metric to U S 96 pages softbound No 21036 3 50 RE 074 C Send FREE 1974 Sams Book Catalog 007146 State Zip Stocking only 49 ECG semiconductors is like having thousands of audio transistors on hand Manufacturers of TV radio and stereo systems have audio transistor replacements listed under thousands of different part numbers But thanks to the Sylvania ECG semiconductor replacement guide you can replace practically all of them with just 49 different transistors And that can save a lot of hunting and stocking especially when you re a busy service dealer For example if you need a low noise high gain NPN silicon transistor for an audio preamp check out our ECG 199 It tits a lot of sockets And if import parts are bugging you our ECG 158 176 226 and 226MP are direct replacements for parts
211. ppd O Ship C O D Please send ____ Mark Ten B assembled 59 95 ppd __ Mark Ten B Kit 44 95 ppd 12 volt negative ground only Standard Mark Ten assembled 44 95 ppd ____ 6 Volt Neg Ground Only 12 Volt Specify Pos Ground rec Neg Ground Standard Mark Ten Deltakit 29 95 ppd 12 Volt Positive or Negative Ground Only i Car Year Make Name Address City State Zip Cirele 5 on reader service card 13 je The first NEW amplifier design the ORIGINAL Super Amp You remember the first super pow er amplifier the Crown DC300 Well most of its competitors are still using those six year old circuit designs pioneered by Crown Most every amp but Crown s new DC300A a totally redesigned amplifier inside and out Frankly the DC300A is not created for the hi fi mass market but for demanding commercial and professional applications However we know there are discerning audiophiles perhaps like yourself who can appreciate the difference The new DC300A has double the num ber of output transistors effectively twice the muscle of the old DC300 for driving multi speaker systems Each channel has eight 150 watt devices for 1200 watts of transister dissipation per channel Ad vanced electronic output protection per mits the DC300A to drive the toughest speaker loads at higher outputs before go ing t
212. quired in some applications There ll be times when you want to adjust signal levels in dB or smaller steps Therefore a precision at tenuator may be a required instrument in your shop More on this later The square wave output of the audio generator and a scope are useful when you want a quick look at the overall response of an amplifier A square wave fed into an am plifier will provide a rough idea of the re sponse from one tenth its fundamental fre quency up to about the fortieth harmonic of that frequency and will indicate phase dis tortion that cannot be detected in a sinewave test Figure shows some of the various patterns that result from phase shift and amplitude distortion For example a 20 Hz square wave presents a picture of the amplifier s response from 2 to 800 Hz A 500 Hz square wave checks response trom FIG 1 _SQUARE WAVE PATTERNS produced by phase shift and amplitude distortion in an amplifier a The dip between the teading and trailing edges shows amplitude loss at low fre quencies b The dome effect shows low frequency boost c Rounded corners on lead ing and trailing edges are from high frequency tosses d Low frequency phase shift causes top to slope to trailing edge e A slope and dip show low frequency loss and phase shift f High frequency phase shift and low frequency loss g Phase shift and roll off at high fre quencies h Overshoot and damped oscilla tions i Same
213. r detector solenoid control As long as the shutter rotates an alternating signal is generated in the photocell which is used to hold the solenoid As soon as the shutter stops such as when the tape reaches the end of the reel or jams or if the tape sticks and starts to wrap around the capstan a nettlesome problem with cassettes there is no longer an ac output from the photocell and the solenoid control system causes the mechanism to stop and eject in less than a half second A good idea of the performance built into the CD 166 amp is illustrated by the perfor mance measurements of a standard produc tion model Using a standard frequency re sponse test tape with a 50 to 10 kKHz range the playback response was 0 2 dB With the ANRS operative the overall record play frequency response obtained with Maxell UD C 90 tape was 2 3 dB from 35 to IS kHz Distortion at the meter indi cated 0 VU record level was 1 7 THD total harmonic distortion with 6 dB head room to 3 THD The signal to noise ratio was 55 dB at the noise frequencies those that produce tape hiss the signal to noise ratio was 59 dB With the ANRS operative and Norelco chromdioxide tape C 90 the frequency re sponse measured 0 3 dB from 35 to al most 15 kHz but the headroom was re duced to 2 dB the entire industry wide chromdioxide equalization mess needs to be straightened out The signal to noise ratio at the noise frequencie
214. r in the IF strip eliminates the need for critically ad justed traps for eliminating adjacent channel and in channel carrier beats No IF alignment is needed ever Touch volume contro when the remote con trol is used touch switches raise or lower the vol ume in small steps POPULAR ELECTRONICS took a look at the 25 in diagonal picture and said it can only be de scribed as superb The Black Negative Matrix CRT the tuner and IF strip and the video amplifier provide a picture equal to that of many studio mon itors FAMILY HANDYMAN said It s astounding to think that an utter novice can construct a device as com plex as this without ever knowing a thing about electronics or electricity The achievement is even more impressive in view of the result _ And here s what RADIO TV REPAIR said about service vir tually every function of the fa Beene receiver has been broken down to a miniature plug in circuit assembly if trouble va develops you simply pop a out the correct board and M check it yourself Heath S 1 provides free technical con sultation and if you do need factory service as we said the costs are low well below that for conventional color TV insurance protection The plain truth is ELEMENTARY ELECTRONICS said with service and repair costs soaring even for the most insignificant in home repair or adjustment the GR 2000 is the way all color sets wil
215. rangement can often eliminate the need for an antenna rotator 4 95 Jerrold Electronics Corp 200 Witmer Road Horsham Pa 19044 Circle 37 on reader service card ELECTRONIC ORGAN model 70 1260 Solid state spinet home organ with two 44 note overhanging keyboards and 13 note radial arc pedal keyboard Tonal resources are at fingertip command from rich mellow bass sounds to brasses and woodwinds that have built in wha wah sound Two 35 watt rms amps and two wide range 12 in heavy duty speakers Also fea tured is accessory panel for installation of cas sette recording equipment earphones for silent practice plus provision for connecting external tone cabinet Optional rhythm section is availa ble Kits are available in two preassembled pre finished cabinet styles TO 1260W Contemporary model 995 00 TO 1260M Mediterranean model 1045 00 TOA 60 7 Rhythm Section 249 00 all prices are mail order Heath Co Benton Harbor Mich 49022 Circle 38 on reader service card FET MULTIMETER mode FE27 Big Henry includes protection against mechanical and electrical hazards of everyday service Molded acrylic case is backed up by vinyl clad steel spring loaded jew3i meter movement is de signed to withstand the shock of a 10 foot drop internal pretection of sensitive circuitry is pro vided on all functions by diodes and a fuse will withstand 1000 volts dc across input on any range Features 1 5 dc accuracy wi
216. rds in stock when this issue went on sale When these boards are sold there will be a 6 to 8 week delay before additional boards become available eee ee ee re 7 50 ee er ee ee ee 9 50 i eee E eee T 8 45 Soe et eee re ee 8 45 oe ee re A A 8 50 Don ir DE Oi D5 Qe FROM po _ gt OUTPUT PORT D3 O ___ _R_ _e D2 OI ri D1 O a D O ro 1 2 SN7402 QUAD NOR GATE B6 B6 B7 B7 FROM ASCII TO TV TYPEWRITER OR KEYBOARD Ol for proper data output OUT 0I 01M MMI The MMM bits are set to the binary equivalent of the decoder state selected for that particular output port For example 01 O10 1I would output data at output port 3 since 011 MMM 3 The LED Register Display module pro vides you with a visual indication of the con tents of the HI and LO address latches and the memory data In the selected memory lo MARK 8 MINICOMPUTER 0 1 TO 0 47 uF NO CONNECTION a7 J a a5 H a4 G a3 F a2 E D al O 5V 10K TO TV TYPEWRITER CONNECTIONS KEYPRESSED C POWER TO PIN 16 GROUND TO PIN 8 TERTE E Mark 8 Minicomputer to TV Type writer interface The Mark 8 Minicomputer may be used with the TV Typewriter to display compu ter generated information The interface uses either the A or B Output Port strapped to the specific output code 1 7 that you select The A and B output ports have strobe lines which are pulsed during the output cyc
217. re cut off and collector current is shut down so that the in tune lamp is not illuminated The reverse action takes place when the receiver is in tune With little or no voltage developed across R237 Q217 the Zener Diode remains below breakdown voltage Q218 conducts only slightly so that the voltage at its collector is high enough to cause Q219 to conduct and turn on the IN TUNE lamp on the front panel The action Is that of a true gating circuit and the width of the in tune window can be calibrated at the factory so that the user does not find it too critical a task to tune to a station and yet be assured of low distortion reception when the in tune light is on Though VR205 shown in the schematic on Fig 5 is not depicted as a variable potentiometer in the actual receiver it is adjustable hence the des ignation VR instead of just plain R and its adjusted value determines the percentage of total dc swing of the radio detector that should be applied to this novel circuit Differential amplifier pairs Q213 Q214 and Q215 Q216 op erate so that regardless of whether the tuning error results in a positive or negative dc voltage at the output of the ratio detector the end result is always a positive voltage developed across re sistor R237 Figure 6 further clarifies the gating action The additional transistor stages not used or described in connection with either the quieting meter or IN TUNE light circuits are
218. rector Arline R Bailey advertising coordinator Cover pnotograph by Walter Herstatt Cover design by Louis G Rubsamen Radio Electronics is indexed in Ap tta plied Science amp Technology Index and Readers Guide to Periodical NEJ gt Literature Curat Radio Efectronics Published monthly by Gernsback Publications Inc 200 Park Avenue South New York City 10003 Second class postage paid at New York N Y and additional mailing office One year subscription rate U S A U S possessions and Canada 7 Pan American countries 8 Other countries 8 50 Single copies 60c 1974 by Gernsback Publications Inc All rights reserved Printed in U S A Subscription Service Mail all subscription orders Changes Correspondence and Postmaster Notices of undelivered copies Form 3579 to Radio Electronics Subscription Service Boulder Colo 80302 A stamped self addressed envelope must accompany all submitted manuscripts and or artwork or photographs If their return is desired should they be rejected We d s claim any responsibility for the loss or damage of man uscripts and or artwork or photographs while in our possession or otherwise i aaaaaaaaalalalalalaail aaaaaaaali aaaaaaaaalallllll lailMllllMllMlMtllMl l As a service to readers Radio Electronics publishes available plans or information relating to newsworthy products techniques and scientific and technological developments Because of possible variances in
219. river nutdriver set free Easy Buy Plan 2 Any 180 Photofact Sets for 20 down 475 balance payable without carrying charge Plus the 12 40 Xcelite drive socket wrench kit free Easy Buy Plan 3 Any 300 Photofact Sets for 20 down 805 balance payable without carrying charge Plus your choice of the 30 ica Xcelite 99SM service master tool or a 59 95 Craig 2624 portable cassette recorder a Easy Buy Plan 4 Any 400 Photofact Sets for ve 20 down 1080 balance payable without i carrying charge plus an 89 95 Craig 4507 portable electronic calculator free Easy Buy Plan 5 Any 500 Photofact Sets for 20 down 1355 balance payable without carrying charge Plus your choice of a 125 Vaco tool luggage case or the 169 ACT R 10H L U scanner monitor free aC Sr em a a aU las RI SO q Ca HOWARD W SAMS amp CO INC RE X74 4300 West 62nd Street Indianapolis Indiana 46206 am interested in Easy Buy Plan _____ ____ Please send me a Photofact purchase Contract i Name ger eas Company Name Address i Cy a Sat ep My Sams Distributor is l His Address l City State Zp Lee EE ESEE a Circle 7 on reader service card 15 letters TEMPORARY SUBSTITUTE TUNER CONSUMER OPERATION It appears that there are instances of the Castle TV Tuner Subber as well as home made imitations being left con nected to the consumer s TV re
220. rn Roving Rostrum Dip lomat Announcer Half Mile Hailer Sound Cruiser Background Music and Paging system Lists range of accessory items that include extra speakers microphones batteries converters for ac operation and mixers and microphone extension kits Perma Power 845 Larch Av enue Etmhurst Ill 60126 R E Circle 47 on reader service card EXPANDS their line of SYNTHESIZER KITS from the The Ultimate in Ignition Systems ELIMINATES BREAKER POINTS Perfect Timing and Dwell nev r change Xe Eliminates Tune ups Never wears out or needs any Maintenance modular systems all at affordable prices demonstration record including explanatory manual patch charts and scores now available 1 99 ppd catalog free PAIA ELECTRONICS BOX R14359 OKLAHOMA CITY OK 73114 Circle 29 on reader service card The Most Advanced OPTO ELECTRIC SYSTEM The Allison Breakeriess System eliminates the Points and Condenser replacing them with an Opto Electronic Trigger using a Light Emitting Diode and Phototransistor Also completely eliminates wiper arm friction wear The only TRUE Electronic Ignition that you can install for under 100 Gives 40 times more Timing Accuracy than ANY system using mechanical Breaker Points Unlimited RPM Smoother running No timing fluctuation as with Magnetic units Unaftected by Temperature Moisture or Vibration All Solid State Components
221. rn controlled by an electronic graphics sys tem so that figures drawn by a light pen on the system s screen could stimulate electrodes that would present the same pattern to the subject s brain Although crude figures had been pre sented to the brain with earlier apparatus this refined system made it possible to transmit recognizable simple patterns and letters to the subjects Partly as a result of developing these new computer aided techniques the re searchers were able to carry out further studies on previously unresolved prob lems of differences in response to stimuli between totally and partially blind per sons and between those who were re cently deprived of sight and those who had been blind for many years Technician licensing for NY State An act to institute licensing for all tele vision appliance or home entertainment equipment service technicians has been introduced in the New York State Legisla ture given two readings and sent to the Committee on Agriculture and Consumer Protection Under the terms of the bill a temporary license would be granted to all persons who have been engaged in the given type Radio Eiectronics is published by Gerns back Publications Inc 200 Park Ave S New York N Y 10003 212 777 6400 President M Harvey Gernsback Secretary Bertina Baer ADVERTISING SALES EAST Stanley Levitan Sales Manager Radio Electronics 200 Park Ave South New York N Y 10003 212 777 6400
222. rosshatch generator Offered only by NRD transistorized volt ohmmeter and other valuable equipment that can soon have you earning 5 to 7 an hour servicing color sets in your spare time New square cornered Sylvania picture tube 100 solid state chassis Modular construction with plug in circuit boards Automatic degaussing Automatic fine tuning Automatic tint control Automatic color control NRI FIRSTS make learning Electronics fast and fascinating to give you priceless confidence r En E n agar a j i Pa Bi FIRST to give you a complete programmable digital computer with memory you build yourself to learn organization opera tion trouble shooting and programming This remarkable com puter is one of ten training kits you receive with the new NRI Complete Computer Electronics Course g en e FIRST to give you true to life experiences as a Communica tions Technician Every fascinating step you take in NRI Commu nications training including circuit analysis of your own 15 watt phone cw transmitter is engineered to help you prove theory and later apply it on the job Studio equipment operation and trouble shooting become a matter of easily remembered logic FIRST to give you completely specialized training kits engi neered for business industrial and military Electronics Technol ogy Shown is your own training center in solid state motor control and analog computer servo mechanis
223. rporates what Heath has built into their latest color TV The FAMILY HANDYMAN reviewer put it this way The picture quality of the GR 2000 is flawless na tural tints excellent definition and pictures are steady as a rock It s better than any this writer has ever seen Changing channels is uncannily silent thanks to the varactor tuner which does away with chunky old fashioned switches The visual channel readout ends squinting from across the room for ever Finally the clock is a great gadget a pleasure to have at the least POPULAR SCIENCE pointed out more linear IC s im proved vertical sweep regu lators that prevent power supply shorts and an industry first the permanently tuned I F filter The RADIO ELECTRONICS editors said the Heathkit Digital Design an TV has features that are not to be found in any other production color TV being sold in the U S On screen electronic digital channel readout numbers appear each time you switch channels or touch the RECALL button On screen electronic digital clock an optional low cost feature will display in 12 or 24 hour format S ent all elec tronic tuning Its done with uhf and vhf varactor diode tuners 7ouch to tune reprogrammable digital channel selection up to 16 channels uhf or vhf in whatever order you wish there s no need to ever tune to an unused channel LC F am plifier with fixed ten section LC F bandpass filte
224. s Transistors Zeners Trigistors most Semicon duuctors IC s etc Also Shows continuity in cucu and go no go checks Complete with diagrams and instructions No internal scope connections For medium or small production runs Or for hobbyist experinienter engineer or ham ONLY 19 95 CHECK OR MONEY ORDER WHY PAY MORE BOX 14 LESCO ELECTRONICS SKOKIE LL 60076 7400 7401 7402 7403 7404 7405 7406 7407 7408 7409 7410 7411 7413 7415 7416 7417 7420 7422 7423 7425 7426 7427 7430 7432 7437 7438 7440 7441 7442 7443 7444 7445 7446 74L00 74L02 74L03 74L04 74L06 74110 74L20 74130 74442 74H00 74H01 74H04 74H08 74H10 74H11 74H20 8091 8092 8093 8094 8095 8121 8123 8130 8200 8210 74CC00 74CC02 74CC04 74CC08 74C10 74C20 74C42 74C73 CD4001 CD4002 CD4009 CD4010 CD4011 CD4012 1101 1103 5260 7489 8223 1 30 1725 1 45 2 15 1 70 4000 SERIES RCA EQUIVALENT HIGH SPEED TTL 8000 SERtES TTL 25 7447 25 7448 25 7450 25 7451 29 7452 37 7453 SS 7454 53 7460 29 7464 29 7465 25 7472 35 7473 95 7474 50 7475 50 7476 50 7483 25 7486 32 7489 37 7490 39 7491 35 7492 39 7493 25 7494 30 7495 50 7496 55 74100 25 74105 74107 74121 74122 74123 74125 74126 LOW POWER TTL 40 74151 40 74155 40 74171 Aa 74L72 40 74473 40 74L74 40 7
225. s inel schematic 70 FLYBACK TRANSFORMER for all type 2 TV s inci schematic 70 YV DEFLECTION YOKE for all type 8 TV s inci schematic SHARP 110 FLYBACK amp YOKE COMBI NATION zAFT 2 Good for most por R table TV 90 COLOR YOKE For al Rect lar 149 to 25 Color CRT s a 3995 DELMONICO NIVICO COLOR 10 FLYBACK Model N20411 B PHILCO COLOR FLYBACKS Part 32 101 35 1 HO 5 910 95 P 21032 HORS 10 95 For 95 a round color CRT s 1 2 ment complete wknobs 4 TV ALIGNMENT TOOLS For Color 1 49 Moat popular type Latest Compact COLORE YOKE SONY UHF TUNER TRANS ISTOR TYPE exact replace 3 95 4 TV ALIGNMENT TOOLSmost useful aa 1 sortment TV z2 6 TV COLOR ALIGNMENT TOOLS 79 SARKES TARZIAN TUNER 4lamc Model good for all 41 me TY s TUNER SARKES TAR definition amp smoothness 795 COMPLETE with Tubes WESTINGHOUSE FM TUNER 399 476 V 015001 Transistor gt gt WESTINGHOUSE FM TUNER 12DTx 100 Tube UHF TUNER TRANSISTOR TYPE Used 3 95 in all TV sets STANDARO TUNER TRANSISTOA GUIDEO 1 GRIDI 4 Channel closed circuit 76 1398341 A 95 PHILCO TV TUNERS Model 5GJ7 3HQ5 vila igi TE TV TUNER 340137 3 6CG Fig 6GK5 tuhes 5 S AC LINE CORDS Approved 6 WELLS GARDNER TUNER Part 7 ATM 40587 SHAT Tubes WELLS GARDNER TV TUNER 2541243 f61JR 6HAS tubes GE TV TUNER FU x6 328 60157 44148 7 95 PHILCO UHF VHF TUNER 9 9
226. s of pulse regulator circuits for the same reason Here they signal an im crease in voltage by changing the regulator grid bias You ll find some interesting circuits in these hold downs For one example in the Zenith 20CC50 and 25CC50 series a pair of neon lamps is Connected in series across the HV ADJUST control If the control shorts at the low side the high voltage could in crease With the neons in the circuit the increased voltage drop fires them This loads the circuit and prevents the high volt age from rising This is shown in Fig 5 Note another interesting thing the 6JKS and 6JHS pulse regulator tubes used here have dual plate pins The current through the damper is connected in series with the high voltage regulator plate If the regulator tube is pulled from the socket no current can flow through the damper and the sweep high voltage system is disabled In still others the heaters of the high voltage regulator and damper are connected in series If either one burns out the system is again disabled completely Checking high voltage regulators These circuits are actually quite easy to test All you need is vom or vtvm with a high voltage probe Read the high voltage then turn the brightness up and down If the high voltage stays within the limits given 24 to 25 kV it s working Variation should not exceed more than 1 kV If the high voltage reads low and you also have excessive cathode current in the hori
227. s used to send data from the computer to some external device or instrument such as a teletype or perhaps the Radio Electronics TV Type writer Radio Electronics September 1973 Four output latches are provided on the Output Latch module and two of these modules may be used with the Mark amp The second module may however only use three of the output latches Note that data is sent trom the LO ad dress latch to each output port and that these connections are in parallel The computer decides which latch is activated according tothe OUTPUT instruction that we have in our program Here again the HI address latch holds the control bits B C and D which are decoded and NORed with OUT to activate the selected eight bit output port or latch NOTE The OUTPUT instruction in the Intel User s Manual has two RR bits shown in it These bits must be set to RR PRINTED CIRCUIT BOARD ASSEMBLY is a stack of six 2 sided boards Molex connectors and cables are used to interconnect the boards and to connect the boards to the front panel controls All resistors are 14 Watt 10 CPU BOARD C1 33 pF disc C2 thru C6 0 1 uF disc IC1 10 4 IC6 IC7 IC9 1013 1C17 IC19 7400 IC2 1C 3 IC14 7476 Dual JK flip flop ICS 1011 1016 1C20 1C21 7404 IC8 IC12 7474 dual D flip flop IC22 IC23 IC25 74L04 hex inverter low power IC10 1C18 7410 IC 15 7420 IC24 8008 Intel microprocessor IC26 7442 decoder
228. s was 54 dB The recorder s overall record play wow and flutter was a surprising 0 09 a value more typical to quality reel to reel recorders rather than cassette mechanisms It is pure conjecture but the low wow and flutter might be due to the optical eject which keeps extraneous pressure from stretching the tape Even excluding the ANRS the JVC CD 1668 cassette deck has several features which are forerunners of things to come in quality cassette equipment R E CATALOG DISCOUNT TEST EQUIPMENT SPECIALISTS S ENCORE LAS ern mM rA Leau COMPLETE LINE OF ELECTRONIC SUPPLIES ICC Mullard amp Raytheon Tubes Telematic Test Rigs TV Tuner Subber FREE CATALOG FORDHAM B SITER Co fo 558 Morris Ave Bronx N Y 10451 Tel 212 585 0330 Circle 63 on reader service card clele gt apolo me 15 Watt Miniature Plug In I Soldering iron ORYX the tiny iron for service work lab production Needs no transformer weighs only an ounce plus cord Heats so quickly reaches 725 F in about a minute Light weight small size let you work al day without fatigue Just the thing for tiny components delicate circuits working in close quarters Many replaceable tips Controlled Temperature Soldering fron ORYX Model 50 iron affords close control of temperature from 400 to 750 F 50 watt element gives fast heat quick recovery from heavy joint loads Temperature adjustable while iro
229. scanners CB SSB AM crystals SURPRISE Build inexpensively the most un directories Catalog 25c G ENTERPRISES Box usual test instruments futuristic gadgets using 461R Clearfield Utah 84015 numerical readouts Catalogue free GBS Box RADIO amp TV tubes 36c each One year guaran 100B Greenbank W Va 24944 teed Plus many unusual electronic bargains SEMICONDUCTOR and parts catalog J amp J Free catalog CORNELL 4217 E University San ELECTRONICS Box 1437 Winnipeg Mani Diego Calif 92105 toba Canada E SLA 3 7 segment LED readouts TRANSISTOR SPECIALS CIMOS DIODE CLAMPED 77 numbers 45 Ma seg red A PUF ee ae 3 zB R A oe o at 75 e A RPE 2N11378 PNP GE 10 3 pe ce cy e e TO ro 1 95 74C 165 ox ancwen en 3 50 ae ay POTS 2N2226 NPN S 10 82 2 50 CD 4001 mat 6S K 10K 20K 25K 50K 100K mps3393 NPN Si TO 92 4 1 00 CD4002 65 75 3 2 00 2N3866 NPN Si TO 5 75 CD 4009 1 50 2N2369 NPN Si TO 18 5 1 00 CD 4010 BO MULTI TURN TRIM POTS 2N3767 NPN Si TO 66 70 CD4011 Lg une ee 65 Similar to Bourns 3010 style 2N2222 NPN Si TO 18 5 1 00 CD 4012 65 3 16 x 54 x 1 2N3055 NPN Si TO 3 1 00 CD 4013 0 1 60 50 100 500 1000 5000 2N5296 NPN Si TO 220 50 CO 4016 i Be eo 2N6109 PNP S TO 220 55 CD 4022 BEA A 10 000 and 20 000 ohms 2N4898 PNP S T0 66 60 CO 4023 mas
230. scope s graticule will represent the same number of Hz or logarithmic where each decade 20 to 200 Hz 200 to 2000 Hz and 2000 to 20 000 Hz occupy the same number of divisions on the scope graticule A log sweep ts preferable for viewing the overall response while a linear sweep is best when you want to read an exact frequency off the face of the scope as when checking filters recording and playback curves and tone control action A sweep generator should have several sweep speeds typically 2 5 ms fast 250 ms medium and 25 seconds slow to suit the characteristics of the scope s horizontal amplifier or of a graphic recorder Very slow speeds in the order of seconds are needed when using a graphic recorder to make a perman nt record of circuit perfor mance Distortion analyzers Any complex audio signal fed to an audio circuit can be considered as a series of pure sinewaves which we expect to find in am plified but unaltered form in the output of the circuit But distortion in the amplifier produces a distorted output wavetorm that consists of fundamentals and harmonics ot these input sinewaves as well as some sum and difference frequencies resulting from fundamentals beating or heterodyning in non linear circuits in the amplifier This is called Aurmonic distortion The most com mon type of harmonic distortion measure ment compares the sum of the levels of the harmonics with the level of the fundamental and gives t
231. signal path to notch out the fundamental leaving only the harmonics which are read as a per centage of fullscale Since the harmonic distortion meter measures any signal that is present after the fundamental has been filtered out you must be sure to eliminate any stray signal pick up or hum introduced through ground loops Be aware also that some amplifiers show a ris ing THD percentage at low output levels where the equipment s signal to noise ratio is low An intermodulation IM distortion analyzer tests the amplifier s ability to handle mixed high and low frequencies without mutual interaction The test fre quencies are generally 60 Hz low and 3000 6000 or 7000 Hz on the high end Let s as sume that a 60 Hz and 7 kHz note are ap plied to the input of a non linear circuit The higher frequency is modulated by the lower just as audio frequencies modulate the radio frequency carrier in an AM transmit ter However the situation is more com plex We not only have interaction between the fundamentals we can have interaction between each fundamental and the har monics of the other as well as intermodula tion among the harmonics All of these in teractions can produce spurious frequencies that are equal to the sum and difference of the frequencies involved To get an idea of these spurious frequencies generated by in termodulation consider the typical 60 Hz and 7000 Hz test frequencies The spurious frequencies result
232. st neon systems need considerably more drive voltage than the calculator IC s can provide For LED s current is the problem for each individual segment needs a few mils while the digit driver lines may need several hundred milliamperes of drive since a digit driver may have to drive up to 7 segments at once and since multiplexing magnifies the peak to average current ratio additionally by a bunch Figure 3 b shows how two driver integrated circuits the Texas Instruments 75491 and 75492 being typical are used to drive a LED type display Special high voltage integrated circuits are available for neon type displays or discrete circuitry consisting of Darlington connected transistors and resistors may be used Obviously the 9 95 calculator won t be able to afford any inter SEGMENT LINE INPUT FROM IC 7 REQ D 2N3905 HIGH wl 68K VOLTAGE T 7IDENTICAL Circuits TRANSISTOR 2N5401 DIGIT aN m aA A LINE 15K INPUT DIGIT 003 FROM ov ANODES 150K IC ee ee We Re ee 8 REQ D s 100V 6 IDENTICAL CIRCUITS SEGMENT PANAPLEX NEON DISPLAY ORIVE a DIGIT LINE OUTPUTS FROM CALCULATOR IC LITRONIX DL 33 611 LED DISPLAY RESISTORS SET BRIGHTNESS SEGMENT LINE OUTPUTS FROM CALCULATOR IC b FIG 3 DISPLAY DRIVERS ARE NEEDED when the calculator IC cannot handle the current or the voltage required by the readout 0 CALCULATOR 0 IC 1 1 2 2 3 3 4 5 t O 1S OFTEN ENC
233. t If the battery polarity is reversed the cathode will have a negative voltage on it It will go into full conduction and the lamp will light brightly Connected as this circuit is the meter needle will back off scale if the battery is reversed This will be only the lamp current and won t hurt anything If the lamp lights but the meter is reading up scale the diode is shorted If the ammeter needle doesn t move when the battery is connected the first thing to do is check to see if the line cord is plugged in In this type of regulated charger as I said before even if the battery should happen to be fully charged the ammeter needle will flicker slightly if it s working If it doesn t move at all though the line cord is plugged in check for an open fuse or circuit breaker inside the charger If these all check out OK the SCR could be open or not being gated on This can be checked by simply jumping the SCR with a clip lead If current flows now something is wrong with the SCR or its circuitry This will have to be checked out with adc voltmeter The SCR gate should be slightly positive with respect to its own cathode It takes only about 0 4 volt to turn the aver age SCR on You can take the SCR out and check it A shorted SCR will read zero ohms with ohmeter prods either way If the charger works but the current is very low one of the rectifier diodes could be open This will show you an open circuit with prods e
234. t as well as a demodulated audio output and since the de value at the center tapped tertiary winding of the secondary of the transformer will be zero when the tuner is correctly tuned to exactly 10 7 MHz a suitable dropping resistor and a center pointer meter can be connected as shown Now when the set is detuned either above or below 10 7 MHz the meter pointer deflects either to the left or to the right of its center point Generally this meter action is easier to use when seeking center of channel tuning However it too has its limitations The peak to peak value of the ratio detector S curve shown in Fig 4 may well be 2 volts or more and the meter s total excursion is so small that visual center ing of the pointer may well occur over a range of a significant fraction of a volt enough of an error to permit non linear audio recovery when full RATIO DETECTOR 75 kHz modulation occurs in the transmitted signal A quieting meter The meter used in the H K 900 is totally different from ordinary signal strength or center of channel tuning meters Harman Kardon calls it a quieting meter because it actually re sponds to the degree of noise quieting offered by the tuner in amplifying and receiving an FM signal The entire cir cuit board schematic involved in both the quieting meter operation and the new iIn tune indicator of this re ceiver is shown in Fig 5 The output of the conventional ratio
235. t association of ISCET has been carrying on in plant ser viceability inspections has made recom mendations on and given awards for ser viceability The availability of components has been the subject of constant dialogue between organized service technicians and manufacturers The service data phase was Started early last Spring when a group of six independent service tech nicians met with G E s supervisor of training and publications in a day long critique of G E service data Out of that conference and further studies have come seven Criteria for evaluating service data 1 Indexing and filing systems A pro duct may be identified by mode number chassis number or even the retail sales designation A customer may ask for a knob for a Nadir Netherwood TV a re ceiver may come in with only a chassis number or data may be required for a particular model In all these cases ser vice data needs to be indexed and fileable so that the set can be quickly matched to the correct data 2 Accuracy The Technician is well aware of the trouble an inaccurate vol tage or waveform or a wrong component value can Cause 3 Completeness Essential if the job is to be done efficiently and quickly Mis sing voltages and waveforms slow down the work and may affect the quality of the finished job 4 Readability Lost time errors and frustration result from microscopic print and poor printing not to mention am biguously
236. th 15 megohm input impedance designed to reduce circuit loading and eliminate measurement errors in high impecance circuits Ac rms circuit reads true rms voitage within 3 for either sine waves or square waves produced by regulated power THE ORIGINALS First Of Its Kind And Still Firs No 424 4 No 410 9 No 420 9 2 TA TAA No 440 12 No 460G 16 Smooth working machined mating parts that can naver slip out both the tongue and grooves are undercut CHANNELLOCK imitators can t say this Patented reinforcing edge that eliminates Stress breakage again CHANNELLOCK imitators can t say this The smooth jaw version that won t gouge chrome fittings Curved jaw styles that really grab hold of round work Sizes from 4y mighty midget to the 16 monster Important advantages and styles you get only f om SHANN ELLOCK the original tongue and groove plier Reasons why SHANNELLOCK first of its kind is sti i first Be sure you get the genuine CHANNEL LOCK Look for the trade mark on the handle Our Catalog Is Yours For The Asking Send For It CHANNELLOCK INC Meadville Pennsylvania 16335 Circle 27 on reader service card 79 GTO WKeosim DIGITAL KITS NEW BIPOLAR MULTIMETER AUTOMATIC POLARITY INDICATION Model ES 210K Displays Ohms Volts or Amps in 5 ranges Voltage from 10C Microvolts to 500 Resistance from 100 Milli ohms to 1 Megohm Currett
237. th a feedback network around them The collector load of Q205 is tuned to 110 kHz The amplified noise is applied to C2710 D201 D202 and C212 the com bination of which acts as a peak detector voltage doubler Q206 serves as a dc buffer amplifier and the output of its emitter completes the age loop back to Q203 The de voltage output from Q206 applied through R215 and D203 converts this age voltage to a diode drop log characteristic a charac teristic which is important to the ulti mate operation of the quieting meter The resultant de voltage is then applied to dc buffer amplifier Q207 the emitter circuit of which drives the quieting meter VR202 is used to calibrate the meter which reads downscale as quiet ing impreves with signal reception With no signal received the meter pointer reads O at the right of the scale As signal is received and quieting improves the pointer moves down scale along a calibration of numbers reading from zero to ten at the extreme left of the scale The circuitry de scribed is so arranged that the readings correspond almost linearly in dB to the actual quieting obtained An In Tune light indicator The schematic of Fig 5 also shows how another novel circuit of the H K 900 receiver works Transistor stages Q213 through Q219 are used to trigger on an IN TUNE lamp located on the receiver s front panel The de voltage output from the ratio detector via dif ferential amp
238. th assorted problems which all have something to do with blanking circuits This circuit is getting pretty complex in application although it s pretty basic in theory In the older sets if we lost the blanking all we got was a few vertical retrace lines on the screen In the newer sets and most especially in color TV sets hlanking troubles can Cause some re ally weird symptoms Most of these do nor appear to be due to blanking but they are Lets look at the basic circuitry first and then take a look at some of the oddballs Blanking means just what it says We feed two pulses one hortzontal frequency the other vertical frequency into the circuit Both of these occur in their respective sync interval They are fed into some point in the circuit that will make the picture tube cut off so we don t see the syncs in the picture In black and white B W sets they were fed directly into the picture tube a negative going pulse to the grid or a positive going pulse to the cathode In color sets where we split up the signal into B W video or Y and color you may find blanking fed to the video amplifier stages the color amplifier stages or both By feeding the hlanking in at an early stage we can use a low level pulse By definition a blanking pulse must be of such a polarity that it will make the amplifier cut off Nega live going on a tube grid positive on the cathode reverse bias to a transistor base positive for pnp n
239. the quality and condition of materials and workmanship used by readers Radio Electronics disclaims any responsibility for the safe and proper functioning of reader built projects based upon or from plans or information published in this magazine 3 SP oe eae OTT e Quick vs instant The race is on to find a sub stitute to instant on that casualty of the energy shor tage which used to waste our valuable watts feeding current to tube filaments while the TV set was off American picture tube makers are searching for a new design cathode which heats up rapidly Philips of Holland is already manufac turing tubes with a cathode which provides four second warmup and Matsushita of Japan is adopting the same principle And Sony has put a quick warmup cathode in its 13 inch Trinitron for sale in Japan only for the time being American manufacturers meanwhile are studying the situation trying to make sure that quick on doesnt mean short life for the picture tube Titi Sa ee Super 8 TV Like to show your home movies on the ol 25 incher Kodak s Super 8 video player is now on the market It s de signed to accommodate car tridged tapes of the amateur variety and uses a flying spot scanner to develop a color TV signal The compact player is attached to the antenna ter minals of a television receiver The player sells for 1 095 and lest you think that s rather high it s actually 100 less than the originally
240. these in our matrix as in Fig 4 d we end up with a scanning keyboard that only needs two new leads for a 16 key system and only three new leads for up to 24 keys if there are eight digit drivers Pressing any one key connects one of the digit driver lines to one of the keyboard input lines The internal circuitry recognizes the time slot of digit driver pulse and enters the appropriate numeral or machine command While quite a bit of internal circuitry is needed the same circuitry also provides debouncing minimizes the package pins needed and eliminates any need for diodes or other encoding components Any given calculator chip can only work with one of the 4 systems of keyboard entry shown the newer the chip the more likely it will use the scanning configuration of Fig 4 d since it is the best in terms of pins and simplified external circuitry Inside the chip So what goes on inside the calculator chip There are several important circuit areas as the block diagram on Fig 5 shows us These essential parts include the memory stack where numbers are stored the arithmetic unit where simple arithmetic operations are carried out the microprogram where the simple arithmetic unit is told what to do over and over again and in what sequence the keyboard interpreter where numbers are debounced and entered and machine commands add subtract multiply equals etc are sorted out and used to sequence the microprogram finally some h
241. they last Most Often Needed 1926 1950 Diagrams The original Supreme Publications books Sche matics of over 3 000 radio models from 1926 thru 1950 Restore those old sets or use your hooks for valuable historical information a 1926 1938 Volume 600 models 7 00 1940 41 42 46 48 49 50 4 00 each All eight volumes special price 31 50 Quantities of original books are limited Order now and avoid a wait for reprints SEND TODAY to Vintage Radio Dep t R Box 2045 Palos Verdes Peninsula CA 90274 Postage Paid California residents add 6 tax NAME STREET CITY COLLECTORS brightness decrease the value of the resistor But don t decrease it too much or youll burn out the LED This ar rangement has worked great for remote power indicators in industry as pilot lights on home appliances and indi cators in commercial test equipment on the bench Why not try it today Gary McClellan POWER ON INDICATOR SHOWS BATTERY CONDITION A problem encountered when de signing battery powered equipment ts how to include a power on indicator If the device is to operate from a small battery an incandescent lamp would draw too much current Here is a power on indicator which draws little current As a bonus it indicates battery condition As can be seen in the schematic the indicator is a LED connected in series with a Zener diode and current limiting resistor Ri The trick is to starve the LED by selec
242. ting meter s most tmportant function is in helping to orient the antenna for best and that means quietest reception Since quieting is often directly affected by multipath reflections out of phase arrival of reflected signals can often cause cancellation of signal and noisy reception the smooth action of this meter arrangement beats trying to use a conventional signal strength meter which in most receivers hits top read ing point at 40 or 50 mV often well before maximum quieting 1s reached Once the best signal is delivered to the antenna terminals the IN TUNE light then insures that the user is prop erly tuned to it for lowest distortion and best sepuration if it happens to be a stereo signal R E USCET The library just started will be he says a depository of otherwide unavaila ble technicial information a place where you Can deposit that valuable maybe only one of a kind piece of technical in formation that will still be available to you yet be a means of getting a fellow craftsman out of trouble Mr Golden reports to the NESDA and ISCET constituency that he is ready to re ceive help in the program in the form of any and all new electronics textbooks service manuals all old issues of trade and technical magazines as well as service manuals and diagrams of old test equip ment The address is ISCET TECH 8017 Paseo Kansas City MO 64131 More information on how you can give and receive
243. ting a high value for R1 The diode won t put out much light at this current about mil but it does indicate that the equipment is on The Zener diode lets the LED indicate bat tery condition So long as the battery voltage is above the Zener breakdown voltage the LED will light Should the battery weaken the Zener won t break down and the LED will remain dark ON OFF SWITCH od Ima EQUIPMENT BATTERY ao TO EQUIPMENT ZENER DIODE LED TO EQUIPMENT Some design hints Select a low power good quality Zener diode whose value is 1 2 volts below that of the minimum weak battery voltage If the fresh battery voltage is 9 volts and the minimum is 8 then a 6 8 volt 400 nIW Zener would be used To de termine the value for RI hook a variable voltage power supply in place of the battery Set the supply to deliver the fresh battery voltage Then select a value for RI so that the LED draws about one mil Then set the supply to the weak battery voltage Note that any voltage below this will cause the LED to go dark It is best to use a clear domed high efficiency LED for this application When the indicator is connected as shown the LED will light when the power swiich is on Should the LED remain dark it is an indication that the battery needs replacing Robert Liebman R E need belts We ve thousands in stock Ready for immediate shipment Belts for over 1800 makes an
244. ts If you want to develop an efficient and profitable approach to hi fi servicing we have shown in the following listing some of the types of instruments and their pertinent features and specifications The list is not all inclusive We suggest writing to the manufacturers for their general catalogs and additional information on the equipment listed here R E WITH FT umr HANDI ow AEL imm es 1 ERE PY y instruments Ni relay tools Ni wire strippers 7 Ni tool kits Ni cases bags s V tweezers 4 soldering irons Ni drivers N metric tools Ni optics V wrenches mere cee en eee eet ee a SEND FREE CATALOG 674 TO Please l u s Help prevent j i forest fires i Company i 2 Address City State Zip JENSEN TOCOLA and ALLOYS AF H d4th Sheet Frese Ariana Aji BLISS amp LAUGHLIN industry TB Circle 25 on reader service card If You Work In Electronics GRANTHAM OFFERS YOU College Level Training and a college degree Electronic Circuit Design Engineering Analysis includ ing mathematics thru calculus Classical and Solid State Physics Engineering Design Gives etc etc are all part of wo tee the Grantham home study de gree program in Electronics Engineering PUT PROFESSIONAL RECOGNITION IN YOUR CAREER By adding college level home training and a college degree to your experience you can mo
245. ts 25 Pin 9 95 3 for 27 CMIROZ 4 1 pin OP with 3 function memory Adds multiplies subtracts MMS5725 Digits 4 Funct LED 4 95 3 tor 12 and divides Use with 7 MM5736 6 Digits 28 Pin iN 4 95 3 for 12 segment readouts Nixies and LER a DATA SHEETS POCKET CALCULATOR KEYBOA RD _ XCITON or han rel se erly EET A P ori af a Only uaaa 1 MICRO MINI CT 5001 2 12 or Mostek 6 95 TEF YELLOW LED 5010 12 18 feather touch Ws 3 tor pen s 39e keys by FLEX KEY XC212Y 185 x 09f vel 3 tor 18 low diffused lens for indi cator use 2 4V x 10 mils viewings angle 40 Upright XC209Y YELLOW OAK meem For RTTY SWITCHES Printed Circuits cludes 0 to 9 XC524Y a XC522 illumi i wiles 10 switehes o i a al use 14 view an gle Kit of 17 for 6 95 aa e FF oe dot and CE XCS26Y a XCh22Y but fel 10 pc kit o to 9S oni SP E CL and 4 diffused lens indicator use Same type as above 2 95 funetions Hlue with white viewing angle 80 iracters JUMBO YELLOW CLOCK CHIPS 5 Low as WITH DATA SHEETS OLEDS ON A DIP 8 88 Type XC22Y wide angie Doai iNuminater 24V 10 2 Heb ie gaen ree tae See mils 20 viewing angles O MMS313 6 dicit 28 Pin 8 88 340 H x 200 dia Yellow O MM5314 6 digit 24 Pin 8 88 pmen enm O MM5316 4 digit 40 Pin Alarm 13 50 sF noo 1 MM5316 DIGITAL ALARM CLOCK XC 554Y
246. ts it does not put the raster out You ll see an odd symptom the picture will have about six thick black ver tical bars at intervals with the picture show ing between them These are called jail hars for obvious reasons The bars are caused by blanking of the raster due to the peaks of the ringing waveform which are now getting through the diode unclipped The vertical blanking is applied in the same amplifier circuit with another diode It is goes bad we see another odd effect When the brightness controt is turned down the raster will go out from top to bottom exactly like a window shade being pulled down If the diode ts just leaky you may not see a full window shade effect but the ras ter will be shaded from top to bottom the top is usually the darkest Neon lamps You ll also find neon lamps used in blank ing circuits Neons will fire at about the same voltage usually somewhere around 65 volts When they fire they conduct a small cur rent So this too can be used to pass a pulse voltage The neon lamps do sometimes be come defective Strange as this sounds they can become gassy and fire all the time This upsets the blanking They can also crack admit air and refuse to fire at all which also upsets things If you have doubts try a new neon lamp of the same type In some cir cuits you ll find polarized neon lamps These must be replaced by an exact dupli cate and with the nght polarity Blanker trans
247. u Kram Shope wt 3 Ibs With knohs 20 watt Soli Slide Rule Dial mi fy Uri be d State Amplifier id State pose All Family System sual HI FI sterco buy atric System of its kin af lay different funci d at the usnal Printed Circuitry WITH GLASS ESCUTCHEON l IONS j A unit that makes it oly Pak econ POLY PAKS BLUE RIBBON POLICY _ ya 6e ia 20 Yrs of Promp i Ga kA 20 Vex of Busines SERVICE rad 3 INTEGRITY 7 F ae f Money Bach T 20 Yrs of Beonomy e Cor fe GUARANTEES LOWEST PRICES NATIONAL nuy any 3 TAKE 10 LINEAR Op A Zhi Facrory Mannen FACTOR FACTORY TESTr Togr imma E CUARANTEED 2 50 4 MMS260 1024 ise tanle ROM sso LINEAR OP AMPS J 531 Hi slew rate op amp 10 5 2 50 204S Bit RAM i 5 91 532 Micro power 2 50 SaS O LM 300 POS V R super paang Al 533 Micro power 709 Ope Bad OG LM 301 Hi performance 0 8 91 536 FET Input op amp TO DIP 1 17 LM 302 Voltage follower gt F 1 19 D 550 Precision 723 voltage 1 A 1 25 LOWEST PRICES LM 305 Pos Voltage Reg TO al O 555 Timer 2 u SeCands to 210 BRAND NEW A than 741C LECTRIC 3 WATT 2 50 LM 307 Super 741 op amp
248. uare Keystone obiong etc Mura Corp 50 South Service Road Jericho N Y 11753 Circle 44 on reader service card HARDO TO FIND TOOLS CATALOG 68 page catalog contains unusual craftman s hand tools and small power tools used by woodworkers machinistS researchers model makers and metalworkers throughout industry Includes space age glue razor hone professional woodbits pen that writes permanently on met als diamond glass cutter wood chisel sets of twist drill steel funnel with control stopper etc Free years subscription six issues Brookstone Co 4436R Brookstone Building Peterborough N H 03458 Circle 45 on reader service card QUICK GUIDE TO CONSUMER ENTERTAIN MENT INTEGRATED CIRCUITS 4 page catalog lists integrated circuits for such applications as chroma oscillators demodulators amplifiers signal processors as well as video fine tuning systems detector limiters gain blocks stereo decoders rffi f amplifiers duai audio prem plifiers and audio amplifiers Also listed is a complete cross reference between Sprague Cir cuits and those types made by other manufac turers Sprague Electric Co Technical Liter ature Service 81 Marshall Street North Adams Mass 02147 Circle 46 on reader servite curd SOLID STATE PUBLIC ADDRESS SOUND SYSTEMS 6 page catalog specializes primarily in flashlight battery operated complete public address systems Catalog offers seven systems Sound Column Lecte
249. urce modulation input 1 Vrms each channel acroes 1 megohm for maximum output pre emphasis bulit in The 19 kHz crystal controlled pilotis adjustable 45 in phase 0 to 15 in amplitude Power 117 V 50 60 Hz TAPE SPEED CHECKER uses frequency meter type circuitry to check tape recorders for speed and drift Made by Leader the LFM 30 can test recorder speed at 1 2 3 4 5 6 7 8 9 and 10 kHz You can test a 2 speed recorder using a 3 kHz tape calibrated for 3 34 ips and then using the same tape as a 6 kHz test source for 7 2 ips Test range 3 to 3 mp level 100 mV to 10 Vrms Input impedance 150K RECTANGULAR CRT is used in this solid state dual trace wide band oscilloscope that is available as the 0 105 kit from Heath You can display two separate waveforms on channels 1 and 2 channels 1 and 2 alternately 1 and 2 chopped at a 50 kHz rate or 1 and 2 displayed in the X Y mode The vertical amplifiers have put impedances of 1 megohm shunted by 35 pF and frequency response 9 to 15 MHz They are balanced for 5 or less phase shift to 50 kHz Rise time 23 ns overshoot Jess than 10 At tenuators have nine positions varying sensitiv aED ity from 0 05 V cm to 20 V cm Input sensitivity 0 05 V cm The triggered horizontal time base has 18 calibrated sweep rates ranging from 0 2 ps cm to 100 ins cm Sweep also continuously vari abie uncallbrated over the same range Sweep sync delayed 600 ns in auto mod
250. useable as instru ment stand Kit has simplified step by step assembly instructions Both kit and factory wired versions shipped complete with batteries and test leads 5 H x 634 W x 27s D 3 Ibs S a nd name of nearest distributor lt m m e e F a a e end FREE catalog of complete EMC fine RE 7 ELECTRONIC MEASUREMENTS CORP 625 Broadway Hew York H Y 10012 is the least expensive full function digital multimeter you can buy meters the Model 134 delivers digital precision at analog prices AC current and resistance through a tatal of 22 range scales No interpoiations are necessary DEBEL th MERAL MULTHMETER l H Lars PREC A FULL RANGE 5 FUNCTION 3 2 DIGIT MULTIMETER Data Precision s new Model 134 18900 And the specs speak for themselves basic accuracy of 0 2 reading 02 is with autopolarity auto decimal Positioning and 100 overrange Optional isolation and High Voltage Probes available To get your hands on a 134 simply contact the representative nearest you for immediate delivery A real workhorse Designed as the first real alternative to analog AL 705 533 5696 Ma i617 F735 0198 NY i5 576 482 1500 Measurements appear on a bright segment az 60219949519 MO 90315522200 OH NI 216 775 4560 planar gaseous display a full half inch tall and 312 CA IN 409 7335000 MI 1313 4821229 OH 1S 513 298 3033 di its w de Ca iS 17941500 7160 MN 1612 78
251. used no sche 74154 matic is available EACH 6 95 74163 74180 LM703 74192 RF IF amp epoxy TO 5 74193 EACH 45 TEN FOR 3 50 74195 LINEARS NE540 2 00 NE555 1 50 CAA30185 NE560 3 25 CA3025 NE561 3 25 CA3045 NES6S cedeo LMIOO cs CAD OS es lt M302 a 00 LM308 Memorylb 74sz06 1x256 Bipolar TTL RAM 45 ns One bit wide by 256 deep random access memory 3 Chip en able lines Output is compliment Com M311 plete data Sup LM370 2 plied LM703 EACH 3 95 LM309H 10 FOR 32 00 LM309K TRIAC 1 00 LM3900 LM1595 4 quad mult 2N6344 600V 8A TO a ar a MV 50 Red Emitting 10 40 MA 2V 20 10 1 100 10 00 MV 5024 Red TO 18 High Dome 2V 35 10 2 95 MV 10B Visible Red 5 70MA 2Y 30 10 2 50 CA3065 IF Amplifier Limi ter FM Detector Electronic Attenu ator Audio Driver all inone DIP 75 MAN 3 Seven segment readout EACH ONLY 1 TEN OR MORE EACH 1 MAN 1 LED Display 3 MAN 4 Seven segment DIP 2 SEND FOR FREE FLYER A11 ICs new and fully tested leads plated with gold or solder Orders for 5 or more are shipped prepaid smaller orders add 55 California resi dents add Sales Tax ICs shipped within 24 hours BABYLON P D Box 41727 Sacramento CA 95841 ELECTRONICS 916 334 2161 C 0 0 PHONE ORDERS ACCEPTED 10 MINIMUM Circle 79 on reader service card 93 WHOLESALE
252. ve up to greater opportuni ties in electronics Grantham offers the A S E T degree by corre spondence After earn ing this degree you may continue with additional correspondence plus a 3 day residential seminar and certain transfer credits to earn the B S E T degree Then the B S E E is available through further study GRANTHAM SCHOOL OF ENGINEERING 2000 Stoner Ave Los Angeles CA 90025 Telephone 213 477 1901 Worldwide Career Training thru Home Study Mail the coupon below for free bulletin Grantham School of Engineering 2000 Stoner Ave Los Angeles CA 90025 I have been in electronics for years Please mail me your free bulletin which gives details con cerning your electronics degree programs Name___ SFSFSFSFS C CSCsSC C SCS 7S 7 CSCC rir Address a a a a Circle 26 on reader service card 77 SE new products More information on new products is available from the manufacturers of items identified by a Reader Service num ber Use the Reader Service Card inside the back cover SPEAKER SYSTEM LST 2 represents a blend ing of drivers used in other AR systems Cross over network and spectral balance switch permit three repeatable spectral energy profiles that allow the user to select the energy output best suited for room acoustics and program material Geometric design of the cabinet along with the characteristics of the drivers in the three planes results In unifor
253. ver an applied tine voltage range of 90 to 150 Vac the limits of the test equipment Of notable interest the platter can be held with the hand say for cueing purposes with no possibility of damage either present or potential When released the platter comes up to speed almost in stantly The pickup arm has an integral stylus force adjustment with a micrometer type counterweight adjustment Somewhat un usual the stylus force adjustment has an au tomatic Zero reset when the arm is counter balanced It works this way After the pick up is installed in the plug in holder the stylus force adjustment is rotated until the pickup arm is balanced Then the stylus force ad justment is pulled outwards causing the in dicator gauge to automatically reset to zero Then the desired stylus force is simply dialed in This feature is a particularly con venient for those using several pickups say for mono stereo and CD 4 it takes but a few seconds to balance and dial in the force for each pickup The stylus force gauge is calibrated trom 0 to 4 grams in 2 gram in crements and the stylus force can he set within gram accuracy A calibrated anti skate adjustment ts provided as well as a viscous damped cueing device pickup arm lift The connecting cables from the pickup are low capacitance making the system in stantly ready for C D 4 pickups The turntable and arm are mounted on a massive aluminum deck which sits on four acoust
254. y MEDIUM JUMBO tBlue top R A ee 55 high 0 8 J ka thi hen ircuit E YELLOW LEDS white characters Nie or oiai s 6t xt XC522Y 3810 x 160 vel Slack numbers O 7 7 low clear lens point indi e cator use 2 4V 10 mils CALCULATOR Each switch made by Oak Upright Viewing angle 65 KEYBOARD mg 415 ae normally open SWITCH KITS Se op 10 aihen A Y 8 DIGIT LED E 20 Years of Business 3 Basic Kit 1 INTEGRITY Includes Case n A by Flex Key i CT S 002 Calculator chip for 8 digits your 20 Years of Money Santa cholce of three 3 digit readouts sheets j GUARANTEES t Ter 20 Years of Prompt PLASTIC TO 136 Package SERVICE i VOLTAGE REGULATORS 20 Years of Economy O L 129 5V 600ma 2 10 e W 1 O L 130 12V 500ma 2 10 _B4y 3 j CONE RARIGE S m L 1311 15V 450ma 2 10 Take 10 a aa eae MUX D DIGITAL CLOCK PC BOARD tarh board properts plexed far K dignis t ODMAN 1 Litronics 707 MAN 1 MAN 1 MAN 2 s NMAN MAN 3 Litronics 704 MAN 4 Litronies MAN MAN 4 Opcoa SLA 1 MAN 1 ml TO CMAN i 2 50 ae N lari Shove hoard 2 50 pea i r MANT Blec char same as MAN or 4 braces 78 LOWEST PRICES ON NATIONAL tog CALCULATOR 1 CHIPS ON A DIP CALCULATOR CHIPS G CF5001 12 Digits 40 Pin 6 50 3 for i8 Similar to Mostek 5001 CT5002 Volt version of 5001 8 50 3 for 24 Dutperforms Texas 8 disi cCT5005 J2 Digi
255. y hard to get surplus bargains 100 s of charts illus trations For hobbyists experimenters schools in dustry EDMUND SCIENTIFIC CO How Many No 1635EH 8x3x4 24 oz 128 00 Ppd as 300 Edscorp Building Barrington No 08007 Stock No PLEASE SENO _ GIANT FREE CATALOG EH a DE E a pm GET A CHARGE FROM THE SUN Our 12V Solar Battery Charger like those used aboard satellites but rede signed for broad usage allows direct conversion of light to electricity Compact panel put on a boat can au tomatically charge its 12V battery over entire daylite period no power drain at nite Use it anywhere a trickle charge is needed trans radios etc Terrific value it comprises thirty 1 2V silicon solar cells in series w a diode Cap 30 Watt hrs a wk approx 1 971EH 89 95 Ppd Sew S a aa g a PRO ELECTRONIC SOUND CATCHER Parabolic mike w 18 3 4 reflecting shield amp 2 C s in amplifier mag nifies signals 100X that of omni directional mikes Catch a songbird ae ae 1 2 mile off QB s huddle strategy ao sounds never before heard Super gery directivity gives highest signal tox _ noise ratio poss Safe auto cuts off me ear damaging noises Earphones tape recorder output tripod socket Req two 9v trans batt not incl OCTO ETEA cs 9 6 249 8 lt ee RON AE N toe eet a Me etm 299 00 Ppd BIG EAR TO
256. y be coming in from a number of different experiments or sources we must have some means of selecting which data is fed into the CPU Two basic multiplexers are used for this precise gating of data The two 8263 quad three line to one line multiplexers control which of three sets of input lines are selected Note that two sets of these input lines are input ports 0 and These are the two external data input ports The third set of data input lines comes from the memory Data or instructions in the memory all go through the multiplexer and into the CPU This multiplexer 1s followed by a second set of multiplexers 8267 s These are quad two line to one line multiplexers with open collector outputs which are compatible with the computer bus structure This multi plexer switches between the data selected at the previous multiplexer and data from the Interrupt Instruction Port The use of the Interrupt Instruction Port will be covered in the Interrupt section This second multi plexer may also be in an off or unselected state which is used when data is not to be sent to the CPU module Control lines Slao and SL are sent directly from the CPU in terface logic Remember that when the HI address ts not being used to store a memory address it is used for control signals During an IN or OUT cycle these control signals are de coded and used to select the proper input or output lines for the VO bus The Multi plexer module decodes th
257. y effective 10 00 Free literature DYNA N Box 60R2 Wayland Mass 01778 o ge BURGLAR alarm system do it yourself in Stalled in minutes Free literature EMRAD CORPORATION P O Box 1341 Kokomo In diana 46901 BUILD tuner subber from junk TV Plans 1 TIP Box 188 Bruce Miss 38915 ELECTRONIC ENGINEERING amp INSTRUCTION o TV tuner repairs Complete course details 12 repair tricks Many plans Two lessons all for 2 Refundable FRANK BOCEK Box 3236 En terprise Redding Calif 96001 ELECTRONICS career training at home Col lege level communications FCC ticense broadcasting engineering Free catalog GTI 5540 Hollywood Bv 10 Los Angeles California 90028 DEGREE Program in Electronics Engineering Our 29th Year Free literature COOK S INSTI TUTE Dept 14 Box 20345 Jackson Miss 39209 MOVABLE CROSS HATCH FOR COLOR Tv SET CONVERGENCE 18 50 POST PAID IN USA THE GENERATOR I5 ry WOVemL et CTEM arise A TV TRANSMITTER GENERATING ONE i VERTICAL ANO ONE KRORIZONTAL LINE EACH MOVABLE OVER THE TV SCREEN OUTPUT CONNECTS OIRECTLY TO SET ANTENNA ONLY SAO XG EN 2 OEAL FOR CARRYING IN TOOL CADOY KIT 1S COMPLETE WITH ALL PARTS DIAGRAMS AND INSTRUCTIONS PHOTOLUME CORPORATION WRITE FOR BOX 139 NEW YORK N Y 10016 CATALOG A NEW INSTRUMENT TO USE WITH YOUR SCOPE MULTITRACER Use wilh your present Oscilloscope to trace Resistors Capacitors Transformers Diode
258. y numbers can become tedious after a short while It becomes much easier to con vert the binary numbers to their octal equiv alent and use these direct equivalents in stead There are 48 program instructions to use In programs on the Mark 8 Each program must consist of an orderly logical chain of steps in successive memory locations It data or program steps are not loaded in the correct order the program won t work cor rectly and is said to have a bug in it Those not familiar with the basic operations of a computer and the vartous number systems used will find Computer Architecture by Cax ton Foster Van Nostrand Reinhold New York New York 1970 12 50 an easy to read and understand introduction that should be read before attempting to build or use the Mark 8 The basic Minicomputer consists of six modules I Main CPU module 2 Memory Address Manual Control module 3 Input Multiplexer module Memory module Output module 6 Readout module These modules provide the experimenter with the basic minicomputer configuration Two amp bit input ports are provided for get ting data into the computer and four amp bit output ports are provided to output data to ee on external devices The memory module can accommodate up to 1024 bytes or words of Storage although only 256 words ure re quired to start Manual controls are pro vided for the user and a readout of some of the Important registers is provided o
259. ye ijj book explains what TTL is how it i ean ae ER z works and how to use it 336 pages softbound No 21035 8 95 oe Ul i fi Ns i oe 7 SS ULE AG INTEGRATED CIRCUIT TRANSISTOR SUBSTITUTION EIA HANDBOOK 14th Edition by The Howard W Sams Engineering Staff Since exact replacement of transistors is not always possible this book fills a definite need It lists Substitutions for over 100 000 bipolar transistors Both computer selected substitutes and manufacturer selected general purpose replacements are given An updated and invaluable reference for the serviceman 152 pages softbound No 21040 2 95 STUY wir ls Tere gs L pn STU HOW TO USE INTEGRATED CIRCUIT LOGIC ELEMENTS 2nd Edition by Jack W Streater Lacking previous experience with digi tal logic circuits the engineer or tech i nician will be at a complete loss when design amp TAY he enters the field of integrated cir MULTTUIBRATORS hav te b gt Cartan Mind a RECORDING TECHNIQUES HOWARD W SAMS amp CO INC 4300 West 62nd Street Indianapolis Indiana 462C6 Order from your electronics parts diswibutor or mail to 21075 O 21043 J Howard W Sams amp Co Inc oT Name Send books cheeked at right 3_______ _ enclosed 21035 O a Please include sales tax where applicable 21040 J 21037 O Address 21081 O 21036 O City Circle 2 on reader servi

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