CO-ORDINATOR IMAGE Around STEREOMoveYourSound ACTIVEFILTERS DESIGNING UNIT PROTECTION LOUDSPEAKER CONSTANTS? METER TIME FREQUENCY SPACECRAFT HISTORYOF
...NEWS....PROJECTS....MICROPROCESSORS....AUDIO.. . All kits alsO available as separate packs (e g. P.C.B.. component sets, hardware sets, etc.) TRANSCENDENT 2000 Prices in FREE CATALOGUE. SINGLE BOARD SYNTHESIZER LIVE PERFORMANCE SYNTHESIZER DESIGNED BY CONSULTANT TIM ORR (FORMERLY SYNTHESIZER DESIGNER FOR EMS LIMITED) AND FEATURED AS A CONSTRUCTIONAL ARTICLE IN ELECTRONICS TODAY INTERNATIONAL. The TRANSCENDENT 2000 is a 3 octave instrument transposable 2 octaves up or down giving an affective 7 octave range. There is portamento, pitch bending,a VCO with shape and pitch modulation, a VCF with both low and high pass outputs and a separate dynamic sweep control, a noise generator and an ADSR envelope shaper. Thereis also a slow oscillator. a new pitch detector, ADSR repeat, sample and hold, and special circuitry with precision components to ensure tuning stability amongst its many features The kit includes fully finished metalwork, fully assembled solid teak cabinet, filter sweep pedal, professional quality components (all resistors either 2% metal oxide or 'h96 Metal trim!) and it really is complete - right down to the last nut and bolt and last piece of wire! There is even a 1 3A plug in the kit - you need buy absolutely no more parts before plugging in and making great music! Virtually all the components are on the one professional quality fibreglass PCB printed with component locations. All the controls mount directly on the main board, all connections to the board are made with connector plugs and construction is so simple it can be built easily in a few evenings by almost anyone capable of neat soldering! When finished you will possess a synthesizer comparable in performance and quality with ready -built units selling for many times the price! COMPLETE KIT TRANSCENDENT 2000 PIIIIRMAN ONLY £168.50 + VAT! Comprehensive handbook supplied with all complete kits! This fully describes construction and tells you how to set up your synthesizer with nothing more elaborate than a multi -meter and a pair of ears!
Cabinet size 24.6" x 15.7" x 4.5" (rear) 3.4" (front) WE'VE MOVED! INCREASED CAPACITY AT OUR BIG NEW FACTORY NEW FACTORY UP! MEANS MANY PRICES DOWN! ALL OTHERS FROZEN! PRICES DOWN! TRANSCENDENT DPX DIGITALLY CONTROLLED, POLYPHONIC, MULTI -VOICE SYNTHESIZER ANOTHER SUPERB DESIGN BY SYNTHESIZER EXPERT TIM ORR - PUBLISHED IN ETI The Transcendent DPX is a really versatile new 5 octave keyboard instrument. There are two audio outputs which can be used simultaneously. On the firstthere is a beautiful harpsichord or reed sound - fully polyphonic, i.e. you can play chords with as many notes as you like. On the second output there is a widerange of different voices, still fully polyphonic. It can be a straightforward piano or i honky tonk piano or even a mixture of the two! Alternatively you can play strings over the whole range of thekeyboard or brass over the whole range of the keyboard or should you prefer - strings on the top of the keyboard and brass at the lower end (the keyboard is electronically split afterthe first two octaves) or vice versa or even a combination of strings and brass sounds simultaneously. And on all voices you can switch in circuitry to make the keyboard touch sensitive! The harder youpress down a key the louder it sounds - just like an acoustic piano. The digitally controlled multiplexed system makes practical touch sensitivity with the complex dynamics law necessary for a highdegree of realism. There is a master volume and tone control, a separate control for the brass sounds and also a vibrato circuit with variable depth control togetherwith a variable delay control so that the vibrato comes in only after waiting a short time after the note is struck for even more realistic string sounds.
Cabinet We 36.3" x 15.0" x 5.0" (reer) 3.3" (front) COMPLETE KIT ONLY £299.00 + VAT! To add interest to the sounds and make them more natural there is a chorus/ensemble unit which is a complex phasing system using CCD (chargecoupled device) analogue delay lines. The overall effect of this is similar to that of several acoustic instruments playing the same piece of music. The ensemble circuitry can be switched inwith either strong or mild effects. As the system is based on digital circuitry digital data can be easily taken to and from a computer (for storing and playing back accompanimentswith or without pitch or key change, computer composing etc.. etc.) Although the DPX is an advanced design using a very large amount of circuitry, much of it very sophisticated, the kit is mechanically extremely simplewith excellent access to all the circuit boards which interconnect with multiway connectors, just four of which are removed to separate the keyboard circuitry and the panel circuitry from the main circuitryin the cabinet. The kit includes fully finished metalwork, solid teak cabin., professional quality components (all resistors 2% metal oxide), nuts. bolts, etc., even a 13A plug -you need buy absolutely no more parts before plugging in and making great music! When finished you will possess an instrument comparable in performance and qualitywith ready -built units selling for over £1,200! ORDERING INFORMATION AND MORE KITS POWERTRANINCLUDING THE K,MEtZ HOLE ON PAGE 9 rrru fit
DEsIoNING ACTIVEFILTERS PROTECT/ONONAUNiT LOUDSPEAKER TIME CS TNTS ? FREQUENCY METER. FEATURES
DIGEST 8Ifit matters it's here. DESIGNING FILTERS 17Do it yourself it's easier! HISTORY OF SPACEFLIGHT 24What goes up.... ANTI -MATTER EXPLAINED 32NOTHING to do with Star Trek DESIGNERS NOTEBOOK 37A flash of LED knowledge. AUDIOPHILE 43Atomic theory amplifier? TIME CONSTANTS 49Have you the capacity for this? MICROFILE 53Sinclair ZX 80 examined. TECH -TIPS 57This is all your fault! RAVEN ON 63News from around the world
PROJECTS IMAGE CO-ORDINATOR 68 Moving sound reproduction? PORCH LIGHT 77 Don't be left out in the dark. Image co-ordinating p.68 STATE VARIABLE FILTER 84Two for Project 80 synthesisers. ENVELOPE SHAPER 88 LOUDSPEAKER PROTECTOR 95 Cone preservation device. FREQUENCY METER 99 Linear cycle counter. INFORMATION.
A RECORD NEW OFFER 13 Some cheap discs to slip. ETI NEXT ISSUE 15 Next months machinations. ETI SPECIAL OFFER 41 Seek Seikos here. SUBSCRIPTIONS OFFER 61 Buy 1980, get 1999 FREE!! BINDERS 61 Keeping it all together. ETI BOOK SERVICE 81 Fine print indeed. ETIPRINTS 92 No other way is worth it. Quantum sounding off p.43 PCB FOIL PATTERNS 103 Board level decisions.
EDITORIAL AND ADVERTISEMENT OFFICE 145 Charing Cross Road, London WC2H OEE. Telephone 01-437 1002/3/4/5
Ron Harris B.Sc. Editor OVERSEAS Ian Graham B.Sc. Assistant Editor EDITIONS Tina Boylan Editorial Assistant
Diego M. Rincon Art Director AUSTRALIA : RogerHarrison Dee Camilleri, Enzo Grando, Production Editor Loraine Radmore, Lorraine Stout Paul Edwards, Tony Strakas, Technical Illustrators CANADA : HalvorMoorehead Ray Marston Project Editor Editor John Fitzgerald Project Engineers
GERMANY : UdoWittig Steve Ramsahadeo Project Development Editor Christopher Surgenor Group Advertisement Manager Steven Rowe Advertisement Manager HOLLAND : AntonKriegsman Sandie Neville Advertisement Production Editor T.J. Connell Managing Director
ABC PUBLISHED BY Modmags Ltd., 145 Charing CrossRoad,WC2 DISTRIBUTED BY Argus Distribution Ltd. (British Isles) Memberof the 12-18 Paul Street, London Audit Bureau Gordon & Gotch Ltd. (Overseas) MODMAGS LTD of Circulation PRINTED BY QB Limited, Colchester
Electronics Today International is normally published on the first Friday of the month prior to the cover date.
©MODMAGSLTD.1980 All material is subject to worldwideCopyright protection.All reasonable care is taken in the preparation of the magazine to ensure accuracy but ETI cannot be held responsible for it legally. Where errors do occur a correction will be published as soon as possible afterwards.
ETI JULY 1980 3 F2F44,TIggS148M2p$24727.11442$2$F22111WEiRMSAMMMer234254A24221Emm mmmmmmffffr-rJddddNnNNNrvNNnNNNNnNNnNNNnnNNnNNNNNNnNnnhNNn. !th-TD.'nT23999TL'9Dt.TTMT9S"LlT9T,T9'.2.7.2MT.T.1399.2m74,F8=Epmf44ggpsslvgaregmFsuccium?FL6F,FFggp2gggag2r88812AMTAL=TOru,,2SG,O23,10132,614;gRIgng 00000--"n:IR4FgRsp.4.nramg4.-4,;gtg26,p,n,;;ggsAmilgggA4p2R2EAgms,.2vg2,42RREERREURRRERREREURRAAggwg,WAAAAARURMILW4gUndiagaa§ WSPFSS:IFFFIW/222:erMAAAASSRI:See 012.722mt0 P4422=;rn-A21.-41.83§23829.;=94:=IgqigNq"g -N.. 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EOE41182861FilgHgn PWw4W45MhigivaazalimMIU-umiF§Anxdi EFTT!!::::::!ffT!!!ffLgg 0 .88 Pgggi g (0)<(7'144.1,9P.A4AA22224222A4442222g=242"00"-Mi0e000E000A-000-000000000:0triO ""'"AAO13---112,7,22,57,P,T,R,7.=Ag44V.888P-WALISL.21%,=2IctagroliLM'',-,g;=;32:=!!!R7r4P,M7,4G2'""g,2g,7,8g8ilen""'AR4hMlraM8FMRMTIMIgg2Z.,_,MngHTM5F17M88ManannL922822222222,98nailiEEthttt5ttttW.tttttt EF11^4F22P2M34gFEIFFEHIFfirisE2"FlgsF4:2n3;4"FRFET4644 F WVVVVVVVV.M.M.M.q.92....,<.aE2k42222gE2iiag2221.28E2222222222MW22222'.'W gr.)! 66658556665n668s6deAzze,338838E2i...2.2z21...2.TivvYmYYMilltAlillig!!!!PF=E'T4gs-UakandRrginCiaA2m22, mulOggcc.< m WO 2 - IEF4 FREEEMEMPERMEEF re;FtTEFMIll a Hold and reset buttons plus built-in PSU. Diodes, etc? All these features and more for less than half the price of an ordinary frequency meter. The 3.Have you used or applied analogue or digital techni- DFM2000 has all its components including the displays, switches and transformer mounted on one double sided PC board. Assembly is simplicity itself especially since interwiring has ques? been eliminated. This is a high quality design and will make a truly professional digital 4Are you applying TTL Logic to your home computer? frequency meter that any constructor will be proud to own. Price. Only £64.50 Kit (P&P 65p) Probes. Optional extra £8.75 5. Are you programming your home computer using Ready built and tested- £75.50 (65p p&p) simple software techniques? BASIC Computer Games SWITCHES SLIDE 250V. If the answer is YES to any of these questions then why not VYATFORD'S 550p TOGGLE 2A 250V IA DPDT 14p BOOKSHOP SPST 14 ()PDT c/ over 15p CORNER (No VAT on Some Common BASIC 28p consider turning your hobby into a career - applying your Programs DPST 34p )//6. DPOT 13p Books) 760p 4 pole 2.way 32 BASIC Programs for DPDT 38p 24p knowledge to servicing electronic equipment ranging from PET 4 pole on oft PUSH BUTTON Silicon Chip & You 250p 950p 54p 280 Assembl. Lang Pro- DPDT Black Body basic terminals and data processing machines through to Future With Microelec- gramming 750p SUB -MIN TOGGLE Red. Blue, Grit., Yell tronics 400p advanced micro -processor systems. Z80 Microcomputer SP changeover 59p SRL Latching 125p Illustrating BASIC 250p Handbook SRM Momentary Programming in BASIC 690p SPST on/off 54p We will train you through to advanced technology at the 6502 Assmbl. SPST Wised 125p for Business 690p Lang 85p Programming 750p DPOT 6 tags 70p MINI. Non Locking company training school, fitting the individual in at their C202 Programming the DPDT centre off79p Push to Make 15p Full ASCII Coded 56 6502 750p DPDT biased 115p Push Break 25p own level. Key Practical Intro to Push to c /over 85p KEYBOARD Typo 756 PASCAL 400p ROTARY: Make your own multiway Switch, We have vacancies over the whole of the U.K. especially in Only £39.98 (Incl data) TTL Cook -Book 700p Adjustable Stop She. g Assembly. Accom- the London area, with the successful applicants working KEYPAD 454 matrix CMOS Cookbook 750p modate up to 6 Wafers 90p (P&P please add 40p) Reed Switches E3.50 Mains Switch DPST to r 40p from home, usually in a radius of no more than 60-70 Break Before Make We era1 pole/ 12 way OIL SWITCHES 2p/6 way 3p/4 way 4p/3 way 6p/2 way miles. ASTEC RF Modulators 4 -way SPST 110 Sep 250 6 -way SPST 120 Spacer and Screen We supply all tools and test equipment, plus a company -car Special Widebendwrdth 8 -way SPST 145 ROTARY. (Adjustable Stop) which is available for private use. for Computers 470 1 'RELAYS pole/ 2 to 12 way. 2p/2 to 6 way. 3 Sound Modulator 250 RL6 SPCO 175 pole/2 to 4 way. 4 pole/2 to 3 way 43p RL6B DPCO 215 ROTARY: Mains 250V AC 4 Amp 52p If you are interested, then why not contact Mr. C. M ark- lew on 0249 813771 to discuss your own career oppor- CRYSTALS TRANSFORMERS (Mains Prim 220-24051 ALUM. PANEL 6-0-6V 9-0-9V. 12-0-125 100mA 95p tunities in confidence, or write to: 100KHz 323 3VA: 0-6V 0-65 (PCB mounting) 150p BOXES METERS 455KHz 383 SVA: 6V- 5A 65- 5A, 9V- 4A 95- 4A, 12V- 3A WITH LID FSD 1MHz 323 12V 3A, 155. 25A 155-.254 215p 60,46. 1 008M 395 12V: 4.5V -1.3A 4 5V-1 3A, 65-1 2A 65-1 2A 35251" 55 35rnm 1 28MHz 392 12V 5A 125. 5A. 15V -4A 155 - 4A. 20V -3A 21/455'651' i.) 0 50p4 1 6MHz 323 20V- 3A 235p (30p p&p) 75 O 1005A KODE SERVICES 1 8MHz 323 24VA: 65-1 5A 6C -t 5A, 95-1 3A 95-1 3A 4.4a1,2" 75 0.500,A 1 8432MHz 362 125.16 12516, 15V- 8A 15V- BA. 20V- 6A 452,Ax 1L'2' 75 0 lrnA 2 4576MH: 362 20V- 6A 320P 155p p&p) 4s5'46)se' 90 0 5rnA 3 2768M 323 50VA. 6V -4A 6V -4A, 9V -2.5A 9V-2.56. 12V -2A 4a2'/m2" 80 0 10m4 3.57954M 195 LIMITED 12V -2A. 15V -1.5A 155-1 5A. 205.1.2A 205- 55452" 107 0 :30mA 290 4 000MHz 1 2A. 25516, 255-16., 30V- 8A 30V- BA 6x4x2" 110 0 100mA Station Road, Caine, Wiltshire 4 032MHz 323 365p (60p p&p) 755521/2" 145 0 500mA 4.433619M135 100VA:1 2V -4A 125-46.1 5V -3A 155-34. Els6s3" 185 014 5 OMHz 355 205-2 56 206.2 5A, 30V-1 5A 305-1 5A 1E500" 240 024 5 185M 323 405-1 15A 405-1 25A. 505-1.6 505-14 695p 10541/453" 226 0.255 524288M 425 (74p p&p) (NB p&p charge to be added above 125553" 230 0-50V AC 6 OMHz 323 our normal postal charge 125853" 275 0-3006 AC 6 5536M 200 7 680M 323 VU 8 OMHz 392 VOLTAGE REGULATORS OPTO 445p each 8 08333M 362 IA 003 o ve -ve LEDs with Clips 8 867237M 362 5V 7805 175p 7905 220p TIL209 Red 13 9 375M 323 12V 7812 175p 791 2 220p 4Vta3Vial 1/2" TIL211 Grn 17 t0 OMHz 323 15V 7815 175p - 0.500A 10 7MH: 323 18V 7818 175p - TIL212 Tel 18 0 100u A 12MHz 392 TIL220 2" Red 14 05000A IA10220 Plastic Casing 2 Green. Yellow 695p omit Conquer 14.31818M 362 5V 7805 60p 7905 65p 1BMHz 323 orAmber 18 12V 7812 60p 7912 65p 18.432M 323 Square LEDs, Red 15V 7815 60p 7915 65p Green. Yellow 36 7 Sognsont Dioploys 20 OMHz 323 185 7818 60p 7918 55p 011307 675 27 648M 323 10271 Infra Red40 24V 7824 60p SFH205 Detector 90 711312 3" CA 105 386667M 360 TIL313 3" CC 100inA 7092 Plastic Casing TIL32 Infra Red 58 105 48 OMHr 323 011321 5" CA 115 100 00MHz 323 5V 78105 30p 79L05 65p TI178 Detector 70 BARGRAPH Red 10 TIL322 5" CC 115 Be it career, hobby or interest, like it or not 6V 78L62 30p chi 01704 3" CC e 99 8V 78L82 30p segments 225 DL707 3" CA 99 the Silicon Chip will revolutionise every human 12V 78L12 30p 79L12 65p ETI Projects L5400 255 DL747 6" CA 180 activity over the next ten years. 15V 78L15 30p 79115 66p 120 Parts available OCP71 8Orange CA 250 ORP12 63 Knowledge of its operation and its use is vital. LM 300H 170p FND357 Red 120 for Digital LM327 270p 85 Knowledge you can attain, through us, in simple, LM305H 140p LM723 ORP61 3" Green CA 150 Test Meter, 3$p 2N5777 45 DM900, 60W LM309K 135p TAA550 50p 6" Green CA 215 easy to understand stages. Amplifier LM317K 350p TBA625B 95p 3 to Red CA 150 Learn the technology of the future LM323K 560p TDA1412 150p ISOLATORS 3 1/), Green CA150 System. Send LM325N 240p 78H05 + 5V, 5A 1174 48 DVM176 1750 today in your own home. SAE plus 5p LM3269 240p 596p TIL111 7 85 for list. 78HG +5V to +255 011114 95110 LCD 31/2 Digit 875 AdOk 5A 650p nun LCD 4 Digit 975 LS202 345 LS352 185 4011 24 4050 48 4162 125 4520 115 ININEWEINIE1111 15221 120 L 353 186 4012 24 4051 so 4163 125 4521 250 LS240 225 LS355 65 4013 46 4052 ao 4174 130 4522 150 LS241 225 LS3613 65 4014 85 4053 so 4175 120 4526 150 11111=111111kVmm. LS242 232 L 367 65 4015 85 4054 130 4194 125 4527 160 LS243 232 LS368 85 4016 42 4055 135 4408 790 4528 120 LS244 225 L 373 180 4017 82 4056 135 4409 790 4529 175 LS245 270 LS374 180 4018 28 4057 2650 4410 790 4530 89 LS247 135 L 375 150 4019 48 4059 575 4411 1020 4531 165 LS248 136 LS377 199 4020 99 4060 130 4412F 1520 4532 140 LS249 135 LS37B 165 4021 106 4061 1225 4412V1520 4534 575 rIUTORCOURSL LS251 130 LS379 215 4022 95 4062 995 4415F 550 4536 395 LS253 130 LS384 so 4023 25 4063 120 44156 850 4538 160 ELECTRONICS LS257 115 LS385 420 4024 76 4066 se 4419 320 4539 135 Please rush me deta,ls of your LS258 120 LS386 85 4025 25 4067 430 4422 570 4541 150 ELECTRONICS COURSE LS259 160 LS390 140 4026 180 4068 26 4432 1060 4543 175 LS261 450 IS393 140 4027 48 4069 26 4435 1050 4549 296 LS266 75 LS395 210 4028 82 4070 30 4440 999 4553 440 LS273 180 LS396 199 4029 106 4071 25 4450 350 4554 175 I Name LS275 320 LS398 275 4030 80 4072 25 4451 350 4555 85 LS279 48 LS399 230 4031 225 4073 25 4452 4556 75 LS280 250 LS445 140 4032 125 4075 25 4490E 750 4557 425 LS283 190 LS447 195 4033 175 4076 99 44906 750 4558 130 Address LS290 130 LS490 150 4034 210 4077 es 4501 25 4559 290 LS293 130 LS668 105 4035 125 4078 30 4502 125 4560 235 LS295 216 LS669 105 4036 365 4081 as 4503 76 4561 95 LS298 215 LS670 270 4037 115 4082 26 4506 75 4562 595 15299 420 LS673 750 4038 118 4085 90 4507 60 4566 190 LS300 175 LS674 850 4039 360 4086 90 4508 325 4568 299 LS302 175 4040 105 4089 150 4510 99 4569 250 LS320 270 CMOS 4041 80 4093 89 4511 150 4572 48 Block Caps. Please LS323 460 4000 18 4042 BO 4094 240 4512 98 4580 595 LS324 200 4043 95 4513 225 4581 350 4001 18 4095 105 IPr, . wl I hGut obligation to LS325 320 4002 24 4044 95 4096 105 4514 265 4582 150 LS326 330 4006 92 4045 175 4097 350 4515 299 4583 125 I III 7 LS327 315 4007 22 4046 130 4098 115 4516 120 4584 64 LS346 185 4008 82 4047 98 4099 190 4517 450 4585 140 British National Radio LS347 150 4009 40 4048 65 4160 125 4518 105 40106 L5348 190 4010 46 4049 45 4161 4519 70 Fes & Electronics School. 125 No previous knowledge is necessary. I - Just clip the coupon for a brochure I' ETI JULY 1980 5 Complete Audio Tuner Kits Radio/Audio/Communications Modules LW -MW -SW -SW DC tuned and switched 91072 All switching of bands by a single at 958 pin to gnd. Varicap tuned, with LO output for synth. MW/LW version or MW/LW plus1 or 2 SW bands MW/LW: £15.58 f 1SVV £16.73 VHF Tunerheads Mk III FM Tuner series Carriage for Mk III tuner £3 inc Europes largest stock range for broadcast and communications. Probably also the world's - The Mark III series FM tuner has been updated, and now includes a details in the catalogues and PL. Specials are centre zero tuning meter as standard. The instruction manual has been also supplied in the region 30-220MHz. meticulously revised, enabling easy assembly by constructors of various 944378-2 levels of experience -a preview copy may be purchased for £1.00. Pilot Cancel PLL Stereo decoders (26.45 Mark III A series 'Reference series' tuner modules £171.35 inc. Again, Europe's widest range of stereo decoders Mark III B series 'Hyperfi' modules, with switched including pilot cancel PLL types. The pic shows IF BW, pilot cancel decoder £198.95 inc. the 944378 - pilot cancel including post decoder A matching synthesiser unit will be made available later this year, and can be 26/38kHz filtering and muting preamp output retrofitted to either version. All versions include digital frequency readout/clock, VU deviation meters, 6 preset stations, 10 turn pot manual tuning, toroidal PSU, output level adjustment, 110/240v AC input. Full alignment service available. Switched bandwidth FM IF strips Style and performance - with a real Broadcast FM IF strips for all occasions, including the new 911225 - with diode Power Amplifier 'belt and braces' PSU design. switched narrow filter option, ultra linear phase ceramic filters, 84dB S/N, and 0.04% THD (40kHz deviation). Plus usual things like AGC, AFC, dev. mute, level After a couple of preview comments, it seems that many of you are waiting to hear meter drive. £23.95 (supplied in screen can with 0.1 edge connection system) about the matching HMOSFET power amplifier for the Mk III tuner. Well, it's out Also the 7230 hyperfi series - as the 911225, but with slope controlled AFC that at last- complete with twin toroidal PSUs for comfortable 80WRMS per channel, operates in conjunction with signal level- and an extra IF amp stage for DXing. over 100W peak, but limited by thermal shutdown of the HMOS. 10W -100W log LED output peak indicator, DC offset protection and switch -on pause relay. AC or DC input coupling, direct or relay protected output terminals. The works. Various digital frequency displays Complete kit £178.25 inc. Carr. f5. Only one version of this item: The World's largest range of receiver DFMs is now More features and facilities, thanks joined by the DFM7 (shown) - and L shaped version Preamplifier to DC switching and control design of the DFM3 with remote display mount connector reviewing the most comprehensive audio preamplifier yet DC switching of 7 inputs, plus possibility. 1kHz SW resolution with 455kHz or two tape in/outs. 2 low pass, 2 high pass active filters, genuine volume related loudness, 1dB 10.7MHz offsets, 100Hz res up to 3.9999MHz, and channel matching, with DC volume, balance, bass and treble controls.Suitable for bus/remote VHF to 299.99 MHz in 10kHz steps: £41.75 control, tape dubbing, switched monitor etc. 80dB S/N., THD -75dB or better. Pluggable PU equalization boards, tone control override. Price for complete unit about £149 ex VAT. Semiconductors Components FOR COMPLETE LISTINGS - Most popular types are available - Radio/Communications ICs SEE OUR NEW PRICELIST Crystal Filters ex -stock, and in quantity. CA3089E 2.11 HA1197 1.61 SD6000 4.31 10.7MHz 25kHz Channel spacing 8pole £16.67 CA3189E 2.53CA3123E 1.61 TDA4420 2.59 12i4kHz E17.82 HA1137W 1.95 TDA1072 3.09MC1330P 1.38 2.4kHz SSB £19.78 HA11225 2.47TBA651 2.53MC1350P 1.38 M. nolithic dual roofing filter£2.30 2.24 HA12412 2.81 TOA1090 3.51 KB4412 34.5MHz 1.: 43 loss, 80dB stopband HF KB4420 1.95 TDA1220 1.61 KEt4413 2.24 TI3A120S 1.15 TDA1083 2.24 KB4417 2.53 first filter in synth. RX £36.80 KB4406 0.80TDA1062 2.24 MC3357P 3.16 RC XTALSFM pairs (no splits) £3.74 AM pairs .. £3.57 4/V SL16101.84 SL16262.80 VARICAP DIODES USB/LSB Xtals for 10.7SSB filter £2.88 ea SL1611 1.84 SL1630 1.86 A section from our PL: SL1612 1.84 SL16402.17 0.35 16:1 ratio AM tuning SL16132.17 SL1641 2.17 BA102 The most efficient warning samders yet BB204 0.41 KV1215 9v triple 2.93 Piezo Sounders SL16202.50S16600 4.31 0.41 KV1211 9v dual 2.01 SL16232.80S166403.16 88105 The latest thing in electro-acoustic efficiency. 1mA of drive from 86109 0.31 KV1225 25v triple3.16 SL1624 3.77 SL66903.68 MVAM2 1.93 88212 9v dual 2.25 CMOS will give an SPL of 83IB - 10v RMS drive from CMOS uses SL16252.50 MC14961.44 I 3mA for 100dB SPL at 4.8kHz (88dB at 1.65kHz) se" The data sheets shows various drive circuits,,and give full specifications with regard to broadband responses and power Ltolwas POWER MOSFETS 100W PA's made simple consumption etc.1 off 44pinc. 100 off 28.75p (25p ex vat) race pioneering te 100W comp ementary MOSFET technique Hitachi have developed a range of output devices and drivers that ought to revolutionise opinions and attitudes towards the design of all LF amplification systems. We have a new 48 page application note 1E1.50 inc) and Keyboard switches and caps complete sets of parts, modules and now the new complete PA system (see above). From the world's most widely used switch 2SK133 120v N-ch 100W MOSFET £6.33 2SJ48 Pch complement £6.33 manufacturers ALPS - come the biggest and 2SK135 160v N-ch 100W MOSFET £7.29 2SJ50 Pch complement £7.39 best range of keyswitches, and data entry key- PA101B Kit for 100W MOSFET PA less Heatsink £16.10. £23 inc heatsink/bkt) board switches. The SCM81101 is shown here, with the KT5 2 -part cap (with clear top, to enable ULTRA LOW NOISE PU PREAMPLIFIER easy fitting of your chosen legend. Other types are The HA12017 is the last word in PU preamps, and general low noise audio design. available with built in LED, 900 mounting etc. It is an SIL IC, with 86dB S/N in RIAA configuration, 10v RMS output capability, SCM81101 : 17p, KT5 : 16p - or 29p/pair 0.002% typ THD at 10v RMS output (imagine the overload margin !!).It comfort- ably supercedes discrete circuit designs in terms of price/performance, and takes LCD CLOCKSClocks use 1.5v the art beyond the TDA1042's capabilities.(Replaces HA1457) £1.80 each - or at 15uA only. an RIAA Applications PCB with two ICs for £5.75. Complete with Rs&Cs £9.95. LCD DVM DVM 9v/1mA We have various RC ICs, including NE544 CM161: 7mm LCD 12/24hr, alarms etc £11.44 each RadioControlICsNE5044, and two new ones from OKI CM172: 13mm, 12hr, alarms,timer etc £14.32 each KB4445 4 channel dig.prop. FM TX IC. 30mW out (amplifyable) -£2.30 inc CM174: 13mm, 12hr, min/sec stopwatch £14.32 ea KB4446 4/5 ch. dig. prop FM RX IC. Suits KB4445 or RCME syst. £2.65. KB4445 6 pair: £4.75. New 8 page data sheet 35p + SAE. More RC ICs in list DVM 176. ICM7106 based LCD 3Y:digit £22.36 each CMOS, LPSNTTL, TTL, MPU: Most CMOS is available in low WHAT's NEW at AMBIT volume also L PSN. Standard Listings in the newricelist. /;nears and TTL OK. NEW PRICELIST/SHORTFORM:- Bigger print than our Things like ICM7216B, ICL8038, 8080A, 6800P, 2708, NE555,NE556, etc recent one page list - and vastly extended Contain yourselves, RF fans ! Not yet ready for 28 pages, FOC with AS SAE pse Coming Soon a lull launch until autumn but reviewed here:- If you still need convincing to invest £1.60 in the cats, bemean and get this first. SSB transceiver system : 10kHz to 1000MHz !! (1.50 eachor free POWER MOSFET APPLICATIONS with pairs of HMOS A modular VLF to UHF SSB TX/RX system at last. With the correct first mixer, the basic PCB : and the PA101B covers 10kHz to 1000MHz using LO fed from ext. source Our 2 IC Mullard synth for instance) HANDBOOK bHITACHI And RF PA for TX OP 0.2uV basic sensitivity in HF Typ cost for HF synth SSB RX will be Everything you should know about HMOSF ET devices theory and applications. [oss than 6200 Add an RF PA for full TR X for another E50. See one in our foyer, and marvel. CATALOGUES 60e ira Om. los ft 60 CV/0 PLEASE Comnwreial MA ier. on appbcabon PRICES SHOWN HERE INCLUDE VAT Goods ore Ole.. wb,eco to akplobuidy prim sUblen, POST/PACKAGE CHARGE NOW 35e cflakn New/ pbone a. check d dl doubt Please send an Parts 1.3 SAE with all ambit AMBI T enquiries. INTERNATIONAL catalogues Phone orders by 60p ea, or ACCESS but £1.60 the minimum £5 lot. Callers welcome 200 north Seruice Rood,Brentwood, EOM TELEPHONE (STD 0277) 230909 TELEX 995194 AMBIT G POSTCODE CM14 4SG ETI JULY 1980 6 Introduces DIRECT SELLING- the Ultimate Discount!!! CORAL CARTRIDGES Fast becoming one of the top names MOVING COIL UK's No. 1 Cartridge HEAD AMP MC 81 £48.87 H300 £51.75 777EX £35 T100 £24.75 777E £25 L.1) iooono MOVING MAGNET HEADSHELLS LOUDSPEAKERS 555SX £7.28 S100 £6 555E £14.22 S101 £7 The complete fully reviewed D 100 £38 666E £32.48 S200 £4 range of Videotone Speakers Minimax 11£44 which dominate within their GB3 £50 class. Now at lowest ever prices. GB2 £60 TURNTABLES GBS £207 Sansui SR222 Mkt £69.00 D 93 £40 MICROPHONES JVC LA 11 £64.00 MU 105-22 £29.30 JVC SLQ 3 £140.00 MU 105-12 £22.25 MU 25 C £17.39 ELECTRONICS IN CAR ELECTRONICS This new range of Electronics from Videotone FM AM Receiver with fully integral auto redefines the words quality and value for money reverse cassette £48 to a new high. 10 Watt Cassette player £20 7 Watt Cassette player £15 30 watt amp MC input SA4130 £75.00 Stereo Tuner ST4120 £68.00 Cassette full features SC3200 £98.00 LOUDSPEAKERS 50 Watt amplifier WA7700 £77.00 Small Wedge £2.95 20 Watt amplifier LA2020 £58.00 Door Mount £9.95 Large Door mount £18.00 HEADPHONES SEND FOR OUR HP 90 Headphone £12.65 LATEST FREE BROCHURE HP 80 Headphone £9.69 AND DETAIL LIST OF LOCAL Superbly made with top flight SALES OUTLETS IN THE U.K. performance. rVIDEOTONE 98CROFTON PARKOFTONROAD, VIDEOTONIECR PARK, LLONDON SE4 Tel: 01-690 8511/2 Please send me your Deed Selling Brochure and list of sales o,,I, Name Address ETI 7E10 ALL PRICES INCLUDE VAT ETI JULY 1980 7 so.ritrs I 2 3 4 5 7 8 9I0 II 121314151617 NEWS 1810202I 2223 24 ^5:'61'28241031 Calculate -A- Calendar DIGEST The casio HR10isaslightly out of the ordinary printing MHz, has a selectable resolution calculator, in that apart from all of 100 Hz, 10 Hz, 1 Hz or 0.1 Hz. the usual functions and a 10 digit Continental measurement The period display,ithas the capacity to mode, with a range of 400 nS to 10 print calendars to order. Simply Time S and a maximum input frequency key in any year and month bet- of 5 MHz, can resolve to 100 nS, ween January 1901 and December 10 nS, 1 nS or 100 pS depending OilI= 1099 and it will print out a full An attractive new instrument on the range chosen. conventional calendar. Press add from CSC offers time and fre- Time intervals from 200 nS ICII wm CMS =I eel or subtract and it will print the quencymeasuringcapabilites between a rising edge at the A in- month following or preceding it. plus signal conditioning facilities. put and the next rising edge at B The unit can be used either with The model 5001 has two DC - can be measured, with resolution 0 III ID Ell four AA batteries, rechargeable coupled BNC inputs, both of 1M down to 100 pS. battery pack or mains adapter. plus 20 pF input impedance with a The ratio of cycles appearing CO CI ICI el The HR -10 is 31/2" wide by 63/4" sensitivity of 20 mV RMS. Each at the A input per cycle at B can deep and 13" high. Recommend- has three position attenuator (x1, also be displayed. The unit will III MI lel MI ed price is £35.95 including VAT. x10 and x100), a positive/negative count the number of rising edges So, if you want to find out which goingslopeselectorand a arriving at A before the reset but- n 0 ate® day of the week your Granny was variabletrigger -levelcontrol. ton is pushed, in the count mode. born on.... Maximum frequency at the A in- Power consumption is 10 W. put is specified as 10 MHz and at Themodel 5001 Universal the B input as 2 MHz. Readings Counter -Timer is available at £185 Continental held at the Wembley Conference can be held on the display for a plusVATfrom Centre in London during October Specialties Corporation, Shire Hill Battery variable period. this year.Itwill be an interna- The frequency counter, with Industrial Extate, Saffron Walden, tional show case of electrically a maximum input frequency of 10 Essex CB11 3AQ. Farming powered vehicles. In Great Britain over a thousand'new electric road 980 may well heralda new vehicles are made each year and 5001 ON Nt:341.1. COUNTER -TIMER - TOM -11 11,00 LAVIN. 1era for the motor vehicle, this is only here do electrically powered due to the Chancellor of the Ex- vehiclesrunas many as300 0 /.":1 -/C .71 -1 I- _4& million miles each year. The inten- I I J I I I chequer abolishing Excise Duty from electricvehicles. Thein- tion of the conference and exhibi- *V terest recently shown in this form tion is to prove the reliability and r -- oftransport is beingfurther performance of the electric vehi- strengthened by the forthcoming cle and to extend its acceptability woe aw= say.vowe so*, -Ammo ....01.1,411N11 1111111111sonm.....aans. Drive Electric '80 exhibition to be as a means of transport. back, triplex conversations, group Look Out calland links with the DP600 digital paging system through a Busby coupler. There is also facility for twelve programmable direct call M100 Direct Speech buttons for frequently called sta- Phillips'System is part of a new range tions. The M100 system therefore ofintercomequipmentbeing dispenses with the need fora launchedforthe1980's.Fully large central exchange and the ex- compatiblewiththeexisting pense of wiring every station to it. M100 system,itsbuilt-in Itis available from Pye Business microprocessorenableinstant Communications, Cromwell Road, 'hands free' voice links for bet- Cambridge C B1 3HE. The BBC has ween two and many thousand sta- already shown interestinthis tions and extra stations are simply system by placing a £75,000 order pluggedintotheeightpair with Pye to instal internal com- parallel cable and reprogrammed munications in the Beeb's News withinseconds.Thekeyboard Department at Television Centre, layoutincludes animproved this covers seven floors and in- volume control and privacy but- itially 140 stations will be install- ton as well as standard optional ed. It will replace part of the ex- functions such as automatic call- isting custom-built system. ETI readers can now buy the PCB and chip for a mere £9.95 all Pinball Prices inclusive only if you send off the attached form. Slashed To: Pinball Offer, NIC, 61 Broad Lane, London N15 4131 Please send me the ET! Pinball Pinball Wizard PCBIChip sets at RememberWizard project,featuredin £9.95 per set. I enclose cheque/ the November 1979 issue? It has PO payable to NIC for proved to be so popular (hundreds NAME have been built) that the supplier ADDRESS has made a further bulk purchase of the chips. ETI JULY 1980 CHROMATHEQUE 5000 POWERTRAN 5 CHANNEL LIGHTING ehromatheque 3000 EFFECTS SYSTEM COMPLETE KIT ONLY Panel size 19.0" x 3.5". Depth 7.3" £49.50 + VAT! This versatile system featured as a constructional article in ELECTRONICS TODAY INTERNATIONAL has 5 frequency channels with individual level controls on each channel. Control ofthe lights is comprehensive to say the least. You can run the unit as a straightforward sound -to -light or have it strobe all the lightsat a speed dependent upon music level or front panel control ' or use the internal digital circuitry which produces some superb random and sequencing effects. Each channel handles up to 500W and as the kit isa single board design wiring is minimal and construction very straightforward. Kit includes fully finished metalwork, fibreglass PCB controls, wire. etc - Complete right down to the last nut and bolt! All kits also available as separate packs (eg PCB. component sets, hardware sets etc) Prices in our FREE CATALOGUE. Matching Tuners. See our FREE CATALOGUE DE LUXE EASY TO BUILD LINSLEY HOOD 75W STEREO AMPLIFIER £99.30 + VAT This easy to build version of our worldwide acclaimed 75W amplifier kit based upon circuit boards interconnected with gold plated contacts resulting in minimal wiring and construction T20+20 20W STEREO AMPLIFIER £33.10+VAT delightfully straightforward. The design was published in Hi-Fi News and Record Review and This kit, based upon a design published in Practical Wireless uses a single printed circuit features include rumble filter. variable scratch filter, versatile tone controls and tape board and offers at very low cost. ease of construction and all the normal facilities found on monitoring whilst distortion is less than 0.01%. quality amplifiers. A 30 -watt version of this kit (T30 + 30) is also available for £38.40 + VAT. Above 7 kits are supplied with fully finished metalwork ready assembled high quality teak veneer cabinet, cable, nuts, bolts, etc and full instructions-in fact everything, MUSIC EFFECTS DEVICE AS FEATURED IN 4.01, [1.1,421. VAIVii ELECTRONICS TODAY INTERNATIONAL. LAW!, MOM 1/0.0.1. 0141.1. The BLACK HOLE designed by Tim Orr.is a powerful new musical effects device for processing both natural and electronic instruments. offering genuine VIBRATO (pitch modulation) and a CHORUS mode which gives a 'space,/ feel to the sound achieved by delaying the input signal and mixing it back with the original Notches (HOLES), introduced in the frequency response. move up and down as the time delay is modulated by the chorus sweep generator An optional double chorus mode allows exciting antiphrase effects to be added. The device is floor standing with foot switch controls, LED effect selection indicators, has variable sensitivity input. has high signal i noise ratio obtained by an audio compander and is mains powered - no batteries to change! Like all our kits everything is provided including a highly superior. rugged steel, beautifully finished enclosure COMPLETE KIT ONLY £49.80 + VAT (SINGLE DELAY LINE SYSTEM) De Luxe version (dual delay line system) also available for £59.80 + VAT MPA200100 WATT (rms into 80) MIXER/AMPLIFIER Featured as a constructional article in ETI, the MPA 200is an exceptionally low priced - but professionally finished - general purpose high power amplifierIt features adaptable input mixer which accepts a wider range of sources such as microphone, guitar, etc There are wide range tone controls and a master volume control Mechanically theMPA 200 is simplicity itself with minimal wiring needed making construction very straightforward. The kit includes fully finished metalwork, fibreglass PCBs, controls, wire, etc - complete down to the last nut and bolt 1400*AtIPOR*60A06% COMPLETE KIT ONLY _ 1A7MMATHMAl ,-- , , f - --ion ,a, £49.90 + VAT! a..1 *PA 2017 7. .0.. 0- ,w ,4.046 MATCHES THE MINIM 0 00 CHROMATHEQUE 5000 Panel size 19.0" x 3.5". Depth 7.3" PERFECTLY! NEW FACTORY ON SAME INDUSTRIAL ESTATE PRICE STABILITY: Order with confidence. Irrespective of any price changes we will honour all prices in this advertisement until August 31st, 1980 if this month s ADDRESS AND PHONE NUMBER UNCHANGED advertisement is mentioned with your order. Errors and VAT rate changes excluded EXPORT ORDERS: No VAT. Postage charged at actual cost plus £1 handling and OUR CATALOGUE IS FREE! WRITE OR PHONENOW! documentation U.K. ORDERS. Subiect to 15%* surcharge for VAT No charge is made for carnage, 'or at current rate if changed SECURICOR DELIVERY: For this optional service (U.K.mainland only) add £2 50 POWERTRAN ELECTRONICS (VAT inclusofe) per kit. SALES COUNTER: If you prefer to collect kit from the factory, call at Sales Counter. PORTWAY INDUSTRIAL ESTATE ANDOVER Open 9 a m 12 noon, 1.4.30 p m Monday -Thursday. ANDOVER, HANTS SP10 3NM (STD 0264) 64455 ETI JULY 1980 9 TRANSISTORS BF259 36p TIP304 441p- 203442 1409 40364 120p 104 400V 2000 TT196.0175611 74285 3609 4019 45p 93 SERIES 40408 70, 400p 111F1139 25p TIP30C 60p 203553 240p 25A 400V 74290 1509 4020 100p 9301 160p74500 60p 745114 120p AC126 25p 7400 11p BFR40 25p TIP314 58p 203565 300 40409 NM 74293 150p 4021 110p 9302 175p74504 60p 745124 300p AC127 8 20p 74500 600 25p TIP31C 62p 213584 250p 40410 EIP 74298 200p 4022 100p 9308 316p74505 75p 745132 160p AC176 25p BFR41 ZENERS 7401 12p BFR79 25p TIP324 68p 253643/4489 40411 3009 74365 1009 4023 27p 9310 275p74508 76p 745133 75p AC187,8 25p 27V33V 7402 12p BFR80 25p TIP32C 82p 293702/3 12p 40594 1200 74366 1009 4024 50p 9311 275p74510 60p 745138 225p AF116 50p 400mW SP 7403 14p BFR8I 25p TIP334 90p 293704/5 12p 40595 1200 74367 100p 4025 20p 9312 160p74520 60p 745139 225p 40149 70p 1W 16p 7404 14p 8FX29 30p TIP33C 114p 203706/7 14p 40673 76p 74368 100p 4026 13099314 165p74530 60p 745157 250p 40161 2 45p 90p 74804 90p BFX30 34p TIP344 115p 2N3708/9 129 40841 74390 2009 4027 50p 9316 225p74532 90p 745174 250p AU107 200p 90p 7405 18p BFX84 4.0p TIP34C 160p 203773 300p 40871/2 40p 74393 200p 4028 MO 9321 225p74537 90p 745175 320p BC107 P lip TRIACS 7406 7 30p TIP35A 225p 2N3819 25p 74490 225p 4029 100p9322 150p74564 60p 745194 350p 80109 lip EIFX86 PLASTIC 7407 40p 8F%88 30p 157350 290p 2N3820 50p 74LS SERIES 4030 559 9334 360p74574 900 745241 450p 80111 20p DIODES 3A400V 60P 7408 17p BFW10 90p TI P364 270p 203823 149 4031 200p 9368 200p74585 300p 745260 70p BC147 5 9p BY127 12p 3A 500V 65p 7409 19p 741500 8FY50 30p TIP36C 340p 29386697°4 16p 4033 1110p 9370 200p74586 100p 745373 500p BC149 10p 81X35303 20p BA 400V 70p 7410 15p 741502 200p BEY51/2 30p TIP4IA 65p 293902 700p 18p 4034 200p9374 745112120p745374 500p BCI57 5 10p 0447 9p 6A 500V 811P 7411 24p 741503 BEY90 90p TIP41C 78p 2713933/4 18p 4035 110p 80159 llp 0481 15p 84 400V 75p 7412 20p 741504 16p 45p 1(9424 70p 203935/6 20p 4036 295p LINEARIC9 MM57160 620p 12p BRY39 0A85 15p 8A 503V 7413 301, 741505 25p BCI69C BSX19/20 20p TIP42C 82p 2144036 70p 969 741508 22p 4037 1169 401.0212 600p NE531 150p 80172 12p 0490 9p 12A 403V 85p 7414 40p 811104 225p 11954 160p 2144037 659 120p AYI.1313 668p NE555 22p BC177JI 17p 0491 9p 12A 500V105p 74C14 90p 741510 209 BU105 190p TIP120 120p 294058/9 129 :23S 2950 481-1320 320p NE556 70p BCI79 18p 0495 9p 16A 4001/ 110p 7416 27p 741511 40p BU108 250p 119122 130p 254060 12p 4040 1009 481-5050 140p NE561B 425p 80182 3 10p 04200 9p 16A 500V 130, 7417 27p 741513 40p BU109 225p T1P142 130p 204061/2 18p 4041 80p AY11270 840p NE5628 425p BC184 lip 04202 10p T28C00 130p 7420 17p 741514 720 BU205 200p TIP147 130p 2N4123/4 27p 45p 4042 809 0512244 244 NE565 130p BC187 30p 19914 4p 7421 40p 741815 BU208 200p TIP2955 78p 254125/6 27p 4043 909 4151315 600p NE566 155p BC212/3 lip 19916 7p 7422 22p 741520 20p TI P4055 70p 204401/3 27p 4044 909 '475-13174 775p NE567 I75p BU406 145p 194148 4p 7423 349 741321 40p 80214 lap 34p 204427 90p 1109 CA3019 80p NE571 425p E300 50p TIS43 7425 30p 741527 38p 4046 BC237 15p 294871 60p 194001/2 5p 70p E308 50p 11593 30p THERISTORS 4047 100p CA3046 104151 400p BC327 16p 194003/4 119 7426 40p 741530 20p 50p ITX108 12p 205087 27p IA 50V 44p 4048 55p CA3048 225p 5483209 POA 18p E310 194005 6p 7427 34p 741532 27p 80337 270300 13p 255089 27p 14400V 65 4049 50p CA3080E 72p 54010244 1250p 80338 16p MJ250I2259 194006/7 7p 7428 36p 741537 36p MJ2955 90p ZTX500 15p 205172 27p 344009 90p 4050 49p CA3086 48p SFF96364 1100p 80461 36p 155401/3 149 7430 17p 741538 36p ITX502 18p 295179 90p 84600V 140p 4051 sop CA3089E 225p 51490 400p BC4778 30p MJ3001225p 195404/7 19p 7432 309 741542 70p MJE340 70p 275504 30p 2145191 904 124400V 160p 4052 80p 04309040 3759 SN76003N 250p 7 50p 1S920 9p 7433 40p 741547 90p BC516 2N696 35p 255194 164100V 160p 4053 90p CA3130E 90p S0760130 140p 14 MUE2955 100p 7437 35p 741551 249 BC5470 25697 25p 205245 40p HEAT SINKS 164400V180p 4054 150p 043140E 50p SN76013ND 120p BC548C 9p MUE3055 70p 7438 35p 741555 30p MPFI02 459 29698 45p 205296 55p For 10220 Volt 164600V220p 50p 4055 125p 043160E 100p SN750235 140p BC549C 18p 7440 17p 741573 MPF103/440p 257064 20p 2N5401 50p TmRegs and BT106 110p 36p 4056 135p 04316IE 140p 5076023ND 1200 BC557B 16p 7441 70p 741574 25918 45p 295457/8 40p nsastors 22p C1060 45p 4059 6009 043162E 450p 5076477 200p BC559C 18p MPF105/5 40p 7442A 60p 741575 45p 2N930 18p 2N5459 40p FaTO5 12p MCRIO1 36p 4060 140p 043189E 3009 598515 750p BCY70 18p MPS6531 50p 7443 112p 741576 45p MPS6534 50p 291131:2 20p 255460 60p 11044 35p 110p 4063 120p CA3280 100p 744621 275p BCY71:2 22p 7444 112p 741583 5190406 30p 251613 25p 2N5485 449 BRIDGE 203525 120p 741585 100p 4066 55p DACI4088 200p 534641811 225p 60I31/2 50p 7445 1000 MPS412 50p 251711 25p 295875 250p RECTIFIERS 294444 140p 40p 4067 450p FX209 750p TBA651 200p 60135/6 549 74464 93p 741586 50p 292102 70p 206027 480 IA 508 19p 205060 349 4068 27p 1C17106 850p 164800 90p 8D139 5So MPSA13 7447A 75p 741590 50p MPS420 50p 292160 350p 2N6107 65p IA 100V 20p 295064 40p lop 4069 20p 1C18038 340p TBA810 100p B0140 60p 7448 80p 741592 50p 2522194 30p 296247 190p IA 400V 25p 4070 30p ICM7555 BOp 184820 90p 80189 60p MPSA42 7450 17p 741593 130P 50p 29122224 30p 206254 130p IA600V 309 4071 25p I1356P 95p 184950 300p 80232 969 MPSA43 7451 17p 741596 110p 32p 2523694 20p 206290 65p 2A 50V 309 4072 25p LM100 425p 704940 175p BD233 76p MPSA56 7453 17p 7418107 45p 50p 252484 30p 2N6292 65p 2A 1001.0 35p 4073 250 LM3014 309 1041004 300p 5D235 Shp MPSA70 7454 17p 7415109 809 292646 45p 2501172 150p 2A 400V 45p LOUD- 4075 25p 1M311 120p T041008 320p 70p MPSUO6 63p 7460 17p 7415112100p 60241 292904/5 30p 30128 120p 3A 200V 60p 4076 107p LM318 200p TDA1010 225p MPS1107 90p SPEAKERS 7470 36p 7415113 909 80242 70p 30p 30140 100p 3A 600V 72p 4081 225, 1041022 600p MPSU45 90p 2529064 Sae 30p 7415114 45p 27p 1M319 BOY56 200p 110p 4A 100V 95p 700 7472 50p MPSU65 78p 2529074 30p 39141 21/2" 64R 7415122 80P 4082 27p LM324 TDA1024 120p BF200 32p 100p 7473 34p 0028 130p 292926 9p 30201 110p 4A 400V 21/2" 8R 70p 7415123 70p 4086 72p 151339 75p 10410348 250p BF2401 35p BOp 7474 30p 0035 130p 2N3053 30p 39204 100p 6A 508 2" 811 00p 180p 4089 135p LM348 95p TDA1170 250p BF2568 70p 7475 389 7415124 65p 40290 250p 6A 100V 100p 11/2" 88 600 4093 154377 1759 TDA2002V 325p 32p TIP294 40, 2N3054 7476 35p 7418125 60p sop 8E257/8 48p 40361/2 75p 6A 400V 1209 4094 250p 1M380 75p TDA2020 320p TIP29C 66p 753055 7480 509 7415126 609 4095 9Sp LM381AN 160p 71071 50p 7481 100p 7415132 65p 4096 959 1M709 36p 11072 95p 7482 64p 7415133 30p MEMORIES UART LOW PROFILE OIL SOCKETS BY TEXAS 340p LM710 50p 11074 150p 74834 90p 7415136 559 2102-21 120p 48.3.107541 500p 4098 120p 1M725 350p 71081 4611 7484 100p 7415138 75p 21078 504 AY.5- 10130 4000 10p 18 pit 20p 24 pn 28p 4099 200p LM733 100p 11082 95p 8pit 7485 110p 7415139 75p 2111-2 224 1146402 500p 20 pn22p 28pin32P 40100 220p LM741 18p 11084 130p 14pn11p 7486 34p 7418145 120p 21122 300p TMS6011NC 400p 22 pm25p 40pn 40p 40101 1329 1M747 70p TL170 50p 16 pit 12p 175p 7415147220p 2114 300p 7489 40102 180p LM748 35p 200p 36p 7418148 1759 UAA170 211421 500p CHARACTER 7490A 40103 180p 1512917 250p UON6118 320p WIRE WRAP SOCKETS BY TEXAS 7491 80p 7415151 1009 40271 375p GENERATORS 70p 24 pin 60p 7415153 40104 9Bp 1M3900 UDN6184 320p 4044 3257/00 990p 8 pn 30p 189n 70p 74924 46p 60p 70p 900P 200p 40105 9917 043909 U1412003 1009 4116 5009 MCM6576 612 14 pn 40p 20 pn 75p 28 pn 110p 7493A 36p 7415154 40106 LM3911 130, 40pm 140p 84p 7415155 90p 809 X12206 350p 5101 510p 80-3-2513110 60110 16 pn 96p 22pr. SIM 7494 40107 60p LM3914 250, 4009 74954 70p 7415156 909 012207 6810 3259 R0.3.251310700p 40108 470p LM3915 252p SUBMINIATURE ANTEX SOLDERING 65p 7415157 609 082211 600p 745201 350p 6074526240 9000 7496 40109 100p 044136 120p 675p SWITCHES IRONS 7497 180p 7415158 900 02216 82516 325p 40110 300p M01310P 150p 082240 400p Toggle 0-15W 400p 74100 130p 7415160130p ROM/PROMS KEYBOARD 40114 250p MC1458 48p 25414 909 SPOT 609 C .17W 420p 74107 34p 7418161 100p 71301 700p ENCODER 4502 120p MC14951 350p ZN4190 225p SPOT 65p CCN 15W 420p 56p 7415162140p 745188 225p AY5-2376 900p 74109 4503 70p MC1496 100p 254246 135p DPDT 70p X25 420p 74116 200p 7415163100p 745287 350p 4507 55p MC3340P 120p 25425E 400p DPDT (morea1RBap SPARE BITS 74118 1309 7416154120p 745387 3544 4508 2909 MC3360P 120p 201034E 200p Push to make 150 CX /CC5 46p 210p 74151651609 745470 650p TRANSFORMERS C. 74119 4510 MK50398 750p 95H90 8009 break 2Sp X25 50p 74120 110p 7415166180p 969 745471 650p vona220/24010 4511 150p ML920 775p 10044 Push 'awning SPCO 74121 34p 7415173110p 745571 650p 508 889 609 SPARE ELEMENTS 7415174 110p 4512 1300 750p 9.59 7n4'92p C,CX,X25 180p 74122 48p VOLTAGE REGULATORS 825137 SLIDE DPDT 18p 7415175 110p 4514 265p RAW MimicTCF220 400p 0.120 12500mA250p CCN 200p 74123 48p 93427 ROCKER SPOT 219 7415181320p 4515 300p 14 4- Ve 93436 650p 0.25V 15941 2609 74125 75p 7805 80p 7905 70p WAFER ADCOLA IRONS 7415190100p 45161 110p 59 93446 650p 9-69IA 270p1 K1000 550p 74126 60p 7812 100p 7912 70p 1 P 1215 45p 7415191 104 100p I2V 93448 9043p 12V 24 350p K2000 5509 74128 75p loop 7815 7915 70p 3P , 4W 4Sp 7415192100p I5V 60p CPUs 0-12.15 74132 75p 44520:;? 781860p 7918 70p 41.. /3W 45p. 7415193100p 18V 1500 1200p 20-24-30 14 340p* VEROBOARDS 74136 75p 4526 10Op 24V 7824 410p 7924 70, 2P 600 45p 74137 509 741.5195140p 1802CE 650p 15015 IA 2669' DIP Breadboard 150p 10°.nA 1092 74141 50p 7415196120p 26504 2000p (Please add 50p p&p charge 4 15 x615 270p 4528 120p 5V 7810530p 79105 70p 74142 2009 7415197120p 6502 1000p to all marked above our nor- CRYSTALS (Suitable for 20 x 14 pin or 4532 140p 125 78112 30p 79112 70p IOOKH, 300p 74145 90p 7415221 120p 6800 7013p mal p&p charge) 16 x 16 pin DIL ICs) DIP 4534 550p 15V 78115300 79115 70p 11411: 370p 7415240175p 6802 1250p Breadboard as above with tracks 74147 1900 4538 1209 7415241 175p OTHER REGULATORS 78HGKC 6000 6809 2500p 1008MH: 370p 340p 74148 1509 4543 180p for 31 way connector 170p 1513090 135p 78H05KC 600p 8080A 550p RESISTORS High 3 2768MHz 350p 106p 74150 130p 7415242 4553 4509 vaBoards 1. Cs 170p LM3177 200p 78MG120 135p 80854 1400p Stab 5% E12 3579545MH1 200p 74151A 70p 741.6243 4556 72p 350p No track cubing} 70p 74152441659 174323K 550p 78P05 900p 1558060 10009 Carbon Film 400 74153 4560 250p 8 86723700 400p 74154 120p 74182453509 LM723 37p 79HGKC 700p 280 (10 CONNECTORPLUGS 4569 250p 107441-14 3509 74155 94 7415247 140p 2804 1150p 10R1M 7p / 5pcs 31 way Plug 110p 4572 400 OPTOSLECTRONICS 18MHz 300p 74156 90p 741524131409 120p EPROMS one value 31 way Socket 114 4583 90p 2567/7 45p ORP6O 1/2W 1051 26 690MHz 210p 74157 7415249140p 120p 17024 500p OM 9,3pcs 5.100 &Aboard 112 74 4584 80P 00971 130p ORP61 27145M14, 210p 74159 194 7415251140p 2708 600p one val. 4585 150p ORP12 90p 1(178 70p 140p 2716(45%1 (12 74160 104 7415253 4724 250p 74161 100p 741.5257 120p °PTO -ISOLATORS SUPPORT DEVICES Miniature Presets EDOESOARD CONNECTORS 0.158" PITCH 40097 90p 130p 111111 90p 74162 100p 7415258160p ftD7A 3242 800p Hor /Van 1006.1M 129 2 10 way SSP 2 . 22 way 13Sp 14411 1100p 100p 711112 90p 74163 100p 7415259160p NICT26 3245 4508 Garb. Track Pots 2 15 .0 100P 2 25 way 1809 14412 1100p 111116 909 120p 100p MCS24001110p 5K -1M Log orLtn 2 . 18way 120P 74164 7415266 14433 1100p 6532 1000p 130p 195p LEDS Single 30p 74165 7415273 14500 7009 6820 500P 74166 120p 7415279 90p 0 125 02 6821 500p Single with Swath 60p COUNTERS 14599 290p 16p TTI. & ECL 74167 2000 7415283 170p 11L32 75p TIL220RW 6845 2500p Dual 72p 74C925 475p 0022100350p 18p MC4024 325p 74170 240p 7415298249p 1112098W 13p 111222G, 500p SLIDER POTS 60mrn Track 74C928 60Cp CO22101700p 22p 6850 MC4044 325p 74172 450p 7415324 200p Tft2110, 20p T11228 Rad 8205 320p 119 5K. 10K. 505 100K 1CM72166 E20 Racmnapar 10116 7 74173 120p 7415348 200p '1.212Ye 25p 8212 225p 60p ICK472174 11500 711.216RW 18p LEOs (R G 81 309 LOG 10K 60p 10231 3500pp 74174 90p 7415365 1009 DM8123 1759 8216 225p 191040E 7000 74175 85p 7415367 loop DISPLAYS 8224 400p 0565881 570p 525p 74176 90p 7415368100p 058835 250p 3015F 200p 8228 T11311 74177 90p 741S373180p 01 704 1409 8251 550p SPECIAL OFFERS (subject to stocks) DS8836 150p 111312 3 610p 74178 164 7415374195p MC1488100p 01707 Rai 1409 8253 1200p 555 618/100 7805 E5/10 111321 130p 74180 93p 7415378 200p MC1489100p 707 Gr 140p 8255 550p 741 616/100 7812 £5/10 1609 111330 140p 1100p 74181 7415390 160p 25510 3150p DL747 Red 225p 8257 £6/10 1609 7750 60 200p 2114L-3 £4.00 7905 74182 90p 7415393 75107 160p 747 Gr 225p 8259 10p64 £6/10 74184A 154 7415445140p FN0357 120p DRIVERS 280P10 2708 (450 ns) £5.25 7912 75150 176p 800p 2114L 450ns E24/8 74185 150p 741.5668100p 75154 175p FND500 120p 9638 200p 280010 2708 (650 ns) E4.00 200p 280070 650p 74186 500p 7415669 10Cp 75182 230p FND507 120p 9370 2716 (plus 5V only) £12.00 P&P4-VAT Extra 7415670 4000 UON6118 320p MCI4411 1100p 74188 325p 75322 300p MAN3640 176p 4116 (200 ns) E36 / 8 U0561134 1100p 74190 120p 4000 SERIES 75324 375p 914144640 200p 320p MC14412 74191 120p 4000 15p 75325 375p PROTOBOARD (R) SOLDERLESS BREAD- 16KEY KEYPAD 450pVEROBOAR DS 74192 1209 4001 25p 75361 3009 BREADBOARDS 74193 120p EXP3503 6" it2 1" 3.15 BOARDS (Reed Switches) 015 4002 20p 75363 400p 01 Pkto1100pms 500 120p pin ICs) Socket Strips Bus Strips Binding Posts mountedUHFModulator 6MHz E3.75 (copper clad) 74194 4006 75365 350p 100 to3 14 Spot lace cutter 111110 74195 95p EXP650 3 6" 24" E3.60on slordybase plate UHF Modulator 8MHz E4.50 2 5x 3 75" 48p 43p 4007 259 75451 72p £0.25 Pmonserbontooll1Bp 74196 95p (Up to 1 40 pm 101 PB6 6 . 14 OILICs E9.20Reed SwItches112841 25 5" 57p 51p 4008 80p 754912 989 Vem04/inngPen 80p EXP300 6" 2 1" 6,75F8100 10.14 DIL ICs 611.80 10010 PROBE E18.00 3 75x 375" S7p 74197 4009 40p 8726 250p - +2 wire spools 74198 150p lUto 6 14pin ICS/ P6102 12 .14 OIL ICs E22.98SUPERTESTER 680R E33.00 3 75 x 5" 649 64p 4010 50p 8728 3009 -.- combs 370p 150p XP600 6" 24" E6.30 FB103 24 .14 OILICS E34.45MICROTEST BOR E17.00 3 75 x 17" 222p 194p 74199 4011 259 8195 200p Combs 7p 164 (Up to 1 40pin DC') PB104 32it 1 4OIL ICs 645.95TMK500 E22.00 475 x 17 9" 290p - 74221 4012 25p 8197 200p 74251 140p (The above boards are suitable forallD II ICs I Pocket rnultirnoter E4.75 4013 50p 811595 1400 250p IC TEST CLIPS 74259 4014 849 811596 140p 290p 74278 4015 MP 811597 1400 74279 110p 14 P." E2.60 E4.90 We carry a large stock of 74 and 74LS TTLs. CMOS Linears Memories etc and can normally offer 4016 45p B1LS98 1409 169p t6 per E2.75 40 pin ex -stock deliveries We welcome inquiries for volume quantities both from local and overseas buyers 74283 4017 801, 9601 110p E7.90 74284 360p 4018 89p 9602 22 VAT RATE: Please add VAT at Please add 30p p&p & VAT 1 5% on total order value TECHNOMATIC LTD. Government, Colleges, etc Orders accepted. !17 BURNLEY ROAD, LONDON NVV10 Access and Barclaycard accepted 0 Minutes L)oiiis Hiii tube station) (ample street parking) Mon Fri9 30 530 PleaseSend SAE for list CALLERS WELCOME Saturday 10 30 4 30 Tel: 01-4521500 Telex: 92 800 ETI JULY 1980 10 NEWS:Digest '4P' Martian .**4.4111g4-di.' VINI, W.', 'it 1410.414*- ,...410. tiL '-"...A\ rwro,,a A,- 1,,...... 1 ., Gremlins ... le "..1Sk01..."'.` VI ':'4.1Z ------',..iii- /farms: Mi. a of news from our science cor- r. respondent on Mars - the Viking 2 Lander isn't a well space- 1 - craft at all. Its on -board battery is tL; , ... ,ii.,-.F.4 -Nair .1r-!:.,-.--,-0,21.:I.',4044. presenting a low profile: It'i flat. -_. ,! There isn'tsufficient charge to -,...-.4 ,.....:!...... -..., keep the transmitter going. ----_,s .:.-y..10.....-7,-.3. Viking Lander 2 now sits on 11 the rusty planet at its landing site inUtopiaPlanitia,where the daytime temperature rarely gets above -115°C. It has been working in that temperature since it land- ed there on September 3rd 1976. Circuit Handbook since 1977. Ground -based radardition to the active radar, there is (June) Nimrod the cannot see beyond the horizon. a passive system, carried as sen- The airborne system carried by sors on each wing tip, to analyse VVe missed a denominator out Nimrod canseefurtherand, and classifyradiation received of the equation for E0 ac- Mighty Hunter therefore, give earlier warning of from targets. companying Fig.11 p.60. The first approaching enemy aircraft. Nimrod AEW hasbeen term of the equation should read Nose and tail radomes give designed to be fully compatible (RA + RB)/RB. Also, on p.61, in the ?he latest addition to Britain's the aircraft its odd bulbous ap- with other AEW systems, such as equation for Ein below Fig.12c, Airborne Early Warning (AEW) pearance. The sophisticated avi- the American AWACS. Informa- 'bandwidth'shouldnot be system was recently unveiled at a onics, designed by Marconi with tioncan be transmittedfrom squared.Therefore,twolines British Aerospace airfield 'some- electronic warfare in the crowded Nimrod AEW to the ground, ships, down,'20,000'shouldnotbe where' in Cheshire. The modified airways of Europe in mind, can other aircraft or to virtually any- squared. In the design example Nimrod aircraft is the first of a detect ships and aircraft even where in the world via satellite link. the resistor noise effective resistor fleet of eleven ordered by the RAF. againststronggroundorsea The first aircraftis due to is RAI(RB + RC) 1k0. The ther- The AEW radar system has 'noise' or deliberate jamming and make its first flight in August and mal noise term is then derived been undergoing development can eliminate friendly craft. In ad- enters service with the RAF in 1982. from Fig.12b. Flat Caps ooking a bit like microscopic li- isrequired.Threeworking L quorice all sorts, the new range voltages are available - 50 V, 100 of capacitors from Welwyn Elec- V and 200 V. The components tric are designed specifically for havenoleads.Theyhave micro -microelectronicapplica- palladium silver terminations for tions. The largest of the range is flat soldering onto a substrate or only 3 mm x 2.5 mm x 1.8 mm. PCB. Initial production will cover For further information on values from 1 pF to 100 nF in two the new range of small multilayer dielectrics. BX is suitable for most chip capacitors contact Welwyn applications and NPO can be used Electric Ltd,Bedlington,Nor- where high temperature stability thumberland NE22 7AA. magnifyingglasswithevery order?). They come in values of Choked Up 0.1 uH to 10,000 uH with mini- mum Q from 35 to 95. Thesemilitaryspeccom- Gone are the days when chokes ponents can tolerate up to 1000 V lookedlike lumpy coilsof RMS and if you fancy fixing your wire.The new range ofultra private jet's radio with one, you miniature moulded RFchokes can use it up of 70,000 feet. Ten from RBS Capacitors look more percent tolerant is standard, but akin to the common or garden five percent is available. carbon resistor. For further information on The series 8 chokes have a the Series 8 chokes contact RBS body length of only 5 mm and a Capacitors Ltd, Orchard Works, diameterofonly2 mm (free Vencourt Place, London W6. ETI JULY 1980 11 PRINTER BREAKTHROUGH! PRIME COMPONENTS ONLY £385 + P&P f5 + VAT 80COLUMN HIGH PERFORMANCE IMPACT PRINTER The ideal companion for PET, Apple, LOW PRICES TRS80, Exidy, Superboard, Compukit Also our micro chips are at micro prices. Don't be fooled by low prices. W do not offer for and most Micro's We, surplus, sub -spec or rebranded devices. All our pans are guaranteed new, first quality, factory prime, full spec devices. It is also our policy to offer you the best of new devices that Rugged metal enclosure makes it ideal for become available and these are featured regularly. Prices ere exclusive of p&p and VAT - home computing, small business systems, data logging please refer to "Ordering Information" before ordering. Official orders from Schools, Base 2 Model 800M ST etc College.. Universities and Gov. Authorities accepted. Compare the features: * 96 character ASC II Standard 4040 99p MEMORIES SHIFT REGISTERS * RS -232, 20mA, IEE 488 and Centronics 1/0 * Auxilliary User Defined Character Set * Accepts 81/2" max. paper - pressure feed 91/2" 4041 75p 3341 PCFIFO 700KHZ * 16 Baud Rates to 19,200 930 55p 4042 73p 2102 LHPC 250 NS 125p 495p * 60 Lines per minute - Bidirectional max. paper - tractor feed. 935 4043 86p 2114 450 NS 295p 3341 APC FIFO I MHZ * 5 print densities 72, 80, 96, 120 or 132 PLUS. 937 4044 88p 7114 200 95 325p 550p ,tTractor & Fast Paper Feed/Graphics 944 65p 4045 160p 4116300 NS 335p 3342 PC 64 bit shift rag Chr/Line 99p * 2K Terminal Buffer 946 55p 4047 4116 200 NS 385p star 495p * Self Test Swich 957 55p 4048 56p .1718 250 NS 1895p 3347 PC 80 bit shill rag 962 55p 4049 38p 4315 46 CMOS 450 495p ONLY £19.99 9099 90p 4050 40p 1295p X-RATED CLOCK! Custom high impact moulded 4051 69p DIL SWITCHES WITNHOXV=IrD case with ruby lens. 14.99 4052 75p FPROMS ZULU II CLOCK KIT P&P 82p VAT 1515iT 73p 4 pole 99p 7400 11p 4053 115p 4054 111p 2708 450 NS 450p 6 pole S-TRA VALUE. Alt the components and high quality plated G-10 PC Boards are provided. 7401 12p 27164V450 NS 1395p 8 pole 140p X-TRA CARE IN DESIGN. No wires between readout board and clock board. Large openlayout. 12p 4055 121p 7402 121p 2532 32K 450 NS 3996p 7403 13p 4056 VOL TAG( X-CELLENCE IN IDEAS: 5 years of designed products for the amateur radio market. 4059 560p X-CELLENCE IN INSTRUCTIONS: Clear step-bystep instructions with quality illustrations.The 7405 17p UART5 REGUL A TORS 4060 112p assembly manual is note read-between-thelines afterthought! 7409 18p 4063 112p 55p 7410 16p AY 5-1013/1 29Bp 7805/7812 X.TRA FEATURES: There has never been a clock kit with so many features - at any price! 4066 56p AY 3.10150 350p 7905/7912 65p 7412 18p 422p 575p Una operates on either 12 VAC 0112 VDC. 28p 4067 m6402 350p 789055C 7513 4068 19p r8HGKC 625p On board QUARTZ XTAL TIMMIASE. 7420 16p Automatic BATTERY BACKUP'. Never worry about power failures again! 4069 19p CHARACTER 7430 18p 28p 25p 4070 GENERATOR Reads true 24 HOUR TIME and 31 DAY CALENDAR. 7432 4071 25p Unique NOXtm CIRCUIT activates readouts with a handclap or they can be turned on constantly 7440 16p 25p OC 450p SE 01 Sound Ejtects 4072 When used mobile readouts blank iginition is off. 7442 68p 4073 25p 7448 75p Special NOISE SUPPRESSION and battery reversal circuits. 4075 20p KEYBOARD ENCODER Kit 7473 32p 4076 88p Bright 1/2" LED's show hours. minute and seconds. 7474 32p 4077 23p The SE -01 -is a complete klt that 40p Just clap your hands and the time appears for 5 seconds followed by thedate for 4 seconds. A low 7475 4078 29p of power failures up to 4 hours With 7476 40p contains all cost 9V transistor battery provides stand by power in the event 4081 23p FLOPP DISK the parts to AC 7490 35p 4082 25p CONTROLLERS build a pro FFInt.4D6.. 11.1 EI - the addition of a low cost 1 2V 300 MA transformer, the unit will work on 7492 50p 4085 86p 11.1771 8.01 Single den. g rammab I e 7493 50p 4086 68p sound effects,' -g 4 7496 45p 130p say IBM Compatible Kotitist. 4089 2200p generator -IMit:: 74121 35p 4093 68p Designed ULTRASONIC SENDER RECEIVER KIT 74123 45p 4094 225p 191791 B-01 Dual density beam works like a 74154 90p IBM Compatible 4600p around the TOTAL SECURITY! Completely invisible ultrasonic (23KHZ) Sound 4095 99p new Toms photoelectric beam but is unaffected by light, heat or noise. SeparateTransmitter and Receiver 74157 55p 4096 325p Instruments 74122 45p 110p can be used from 6 inches to 25, feet! A solid object breakingthe beam causes an output to go 4098 S N 76 4 7 7 Complete electronics are 74125 50p 4099 180p 6502 798p Sound Chip. low that will sink up to 150 MA to Drive a Relay. TRIAC, etc. 74195 100p 4501 25p 6504 795p the board provided Works on 12VDC (unregulated) and draws less than 100MA Use it for burglar 74196 100p 4502 112p 6505 795p door bells, electronic rat 140p provides alarms, object counters, automatic door openers, automatic 74283 4503 68p 6800 695p banks of 74290 120p 4507 52p 6802 995p trap(?) and more. ONLY E19.93 P&P 67p + VAT 74365 90p MINI DIP 4508 288p 80804 525p switches and 74366 110p 4510 76p 8085A 1095p pots to pro- 4511 125p Z80 795p gram the a 4L 4512 75p 2804 995p various com- 0)111PaBLE ALARM KiT 741.000 18p 4514 250p Z8001 12500p binations of A fun EASY kit to assemble that emitsan ear piercing 10 74LSO1 12p 4515 290p Z8002 9500p WD9000B 19900p the SIP watt dual tone scream. Resembles European siren Tweet 74LSO4 15p 4516 109p Oscillator. sound. Great for alarms or toys. Operates from 5-1 2VDC ed400°.* 741.508 20p 4518 99p VCO. Noise, at up to 1 amp (using 12VDC 8 ohm speaker). Over 741510 lap 4520 99p SUPPORT DEVICES One Shot. 741511 30p 4521 230p five thousand have been sold. All parts including P AY3-8910 PROGRAMMABLE 20 495p and Envelope Controls. A Quad Op Amp SOUND GENERATOR 741512 30p 4526 105p 6522 795p board, less speaker ONLY £4.99 P&P 67p + VA The AY3-8910 Is a 40 pinL5Ichip with throe 741.514 60p 4527 130p 6531 895p IC is used to implement en Adjustable 38p 99p oscillator, three amplitude controls. pro- 741515 4528 6551 1095p Pulse Generator. Level Comparator and grammable noise generator, three misers. an LM11171 RC ENCODER/TRANSMITTE 744520 19p 4579 140p 6810 375p Multiplex Oscillator for even more' ver- envelope generator. and three D/ A con - 741530 19p 4531 150p 6820 425p satility The 31/4" x 3" PC Board features a LM1872 RC RECEIVER/DECODER utters that are controlled by 8 BIT WORDS. 741032 25p 4532 125p 425p 6827 prototype area to allow for user added New from National The LM 1871 is a complete six -channel digit No external pots or caps required. This chip 741940 26p 4538 150p 6850 425p chip or 741.042 56p 4543 160p circuitry. Easily programmed to duplicate proportional encoder and RF transmitter 6852 power. non -voice unlicensed communication device at cart Buss 18080, Z80. 6800 etc I can be soft. 741947 78p 4556 70p 8212 395p Explosion, Phew Guns, Steam Trains. 85p 4560 225p frequenues ol 27 MHz or 49 MHa with a field strength 0110.00 ware controlled to produce almost any 741948 8214 450p or almost an infinitenumber of other Wand, it will play three note chords, melee 741949 99p 4569 240p 8716 395p sounds. The unit has a multiple of appli- uV meter at 3 meters In addition to radio controlled hobby toy an 30p 4572 46p industrial applications. the encoder section can provide a seri bangs, whistles. sirens, gunshots, explo- 741573 8224 395p cations. The low price includes all parts, sions, bleats, whines, or grunts. In addition, 741974 30p 4584 79p 8228 395p input of six words for hard wired. infrared or fibre opt 4585 125p Assembly manual, programming charts, communication links Channel add logic is provided to control the it has provismns to control its own mentor), 741575 39p 8251 495p chips with two 10 ports The chip requires 741.086 39p 1125p and detailed 76477 chip specifications. It number of encoded channels from three to six allowing increased 8253 design flexibility When used with the IAA 1872 RC receiver) 4-5V 75ma and a standard TTL clock 741090 40p 8755 495p runs on a 9V battery (not included). On oscillator. A truly incredible circuit Only 7415107 40p 30p 8257 1050p decoder, a low cost RF linked encoder and decoder system provides 74C20 board 100MW amp will drive a small two analog and two ON/OFF decoded channels. Super versatile E8.25. 741912389p 74C76 60p 8259 1325p speaker directly. or the unit can be con- 0 page manual with 5-100 interface 741.512550p MC14412VL 797p chip Just out Just look at the features - low current 9V battery 74C85 145p nected to your stereo with incredible operation - on -chip RF oscillator /transmitter - one timing tructionS and several programmin 7415132Hip 74C97 125p Z80 PIO 595p Les 82.25 mitre (No VAT) 741513859p 74098 125p Z80 CTC 595p results! (Speaker not included.) capacitor for six proportional channels - programmable number of 7419151 75p 740107100p 11304 PIO 695p channels - regulated RF output power - external modulator 741015375p COMPLETE KIT ONLY E14.99 bandwidth control - on -chip 4 6V regulator - up to 80 MHz 740160110p Z804 CTC 695p P&P 67p + VAT 741015565p 74C16I145p Z80 DMA 1995p carrier frequency operation 7410161 73p 74C162145p 2804, DMA 2495p LM111/1 E5.50 LM1872 E5.50 Pair 00.50. 7413163 90p 74C163145p 280 510 0 2995p UNIVERSAL SCR m. sheets 25p each. PROGRAMMABLE DUAL OP 7415164 90p Z804 SiO 0 3495p 741S168 190p 74C192175p 30p 2130 SIO 1 2995p C 106D 400V 54 Sale 7415174 99p 74C193175p TRANSCONDUCTANCE Z804 510 1 3495p Intend t°,t'-1=1:r;;" 7410175 99p 740194175p Resistors AMPLIFIER 74C195 Z80 510 2 2995p Kit Includes. 7415195 87p 175p JOYSTICK ICM72211AIDC IC Capacitors 74[903 45p 2804 SIO 3495p Diodes New from National Semiconductor. the 7415221 110p 10 MH. Quart. Crystal LM 13600 is a programmable dual operation 7415244 375p INTERFACE 1 (8) 7 Segment .3" LED Displays Switches IC Socket tranuonductance amplifier designed to be 7415245 675p LINEAR IC's LINEAR PC Board used as a fundamental building block in 7415251 120p Order Part Number ICM722134EV / Kit Only (49.95 3,1350 795p DM8123 125p current controlled amplifiers. filters and 7415257 110p 125p oscillatorsIt can also be used in multi 751529095p 0 3 8910 825p 75150 09 30p 75154 125p RECEIVER ;Senors timers and even sample and hold 741S293 120p WeTHEnd Dynamic ULTIMATE Sound Portable RadioIts a monitor too circuitsIt is well suited for use in electronic 741S366 67p 23 33p 75182 195p 41 18p 75322 250p monitors all 40 CO channels. TV (VHF) PB and W8 organs and music synthesizers because it 7415373 170p can modulate waveshapesvvith ease The 16 7415374 170p C17106 595p 75324 32Sp MODEL 724C. ONLY E29.95 p.p. E4.95 325p 8 Band Receiver pin LM13600 is programmable over six 7415375 140p 01 7107 695p 75325 frail ere lulls row Nee STAR FEATURES AM CBI CB2 TV1 - decades allowing itto function as a basic 7419377 188p 018038 295p 75361 350p CM 72164 1875p 75365 295p Ideal for all video games or remote control FM . P8 WB TVsSwivel Telescopic budding block inabroad range of electroni. 7415393 135p Antenna. Tuning & Battery Indicator AC. DC cany programmable resistors and filtersA 7415490 140p CM72168 1675p 75451 50p protects 2 11/2"H a 214"W k Switch Control DC 6V UM -1(Size DI r 4 remarkable circuit ONLY E1.25 7415670 260p .CM7555 80p 75491 75p Small case size IM301AN 30p 8726 175p 4.5 16"1 4C 220V AFC Switch Control Tone Cori VAT Data 25p r M311 50p 8128 175p 2 Miniature pOtenhOMeters - 40K OHM 1101 Nylon Shoulder Strap or Plastic Handle LM318 75p 8795 175p each 4" PM Dynamic SpeakerDimensions 10 From T 1 TL490 BAR/DOT DRIVER IC. 4001 19p LM324 45p 8T97 175p SPST push button control 230H 22 r D 90mm Drives 10 LEDs with adjustable analog steps 4002 19p LAA339 45p LEDs 5.wve connection cable - 5 fleet long Units are cascadable up to 10 (100 MP.) 4006 75p 1M390 65p 14.209 9p Rugged plastic case NEW Drives LEDs directlyGreat for voltage, 4007 19p L M1496 65p 011.211 13p JVC.4O E4.95 each TUNES SYNTHESIZER JAPANESE TRANSISTOR current or audio displays. Similar in 4008 80p .M1871 550p TIL212 15p Ike 011350 isa MOS microcomputer SUBSTITUTION MANUAL features to 1M3914 with specs and circuit 4009 35p synthesizer of fnprogremmed luta or .M1872 550p TIL220 12p LED BAR GRAPH AND An invaluable Japanese to notes 4010 45p LM3900 50p TIL227 15p applicelloatin lays music boxes and Japanese wbatitution 4011 24p door chimer The standard device 10. I 1M3914 225p 7)1274 18p ANALOG METER DRIVER guideforapproximately ONLY 4012 24p telof 25 Ohm' popular aid Clinic.' LM3915 225p DISPLAYS 3,000 tren.istors. E1.75 4013 38p 1M13600 125p END500 80p New from National LM3914 Drives 10 LED tunes laaftlitios Mee are 3 chum Covers the 254 250 2SC lop 4014 NE555 18p FND510 80p directly for making bar graphs audio power making I total of atlases aao 2SD series to -vg, 4015 75p FEATURES NE556 50p 125p meters analog meters LED Oscillators etc Introduction includes cl 4016 35p END567 Matching red bat display MV57164 E2.25 RC4136 85p 85p Units can be stacked for more LEDs A super Minimal external compiles :tide to understanding 75p 01704 Data 25p 4017 51.176477N 175p 85p versatile and truly remarkable IC Aliteinalic switch elf signal at and of Japanese transistors 4018 76p DL 707 784810045 85p MV57164 Special price Only £2.215 tune 101 power Mina Ordering information. Unless otherwise 42p or 4019 'L071 55p 225p 12 page data 25p Envelope controlto gie organ Only £3.95 matedfor orders under E50 add 50p p&p 4020 88p %.074 130p Matching red bar display MV57164 £2.25 piano quality 100p ISOLATORS Add 15% VAT to total All items are subject 4021 11082 75p Data 25p Sequential lune mod. 4022 88p 120p to prior sale and therefore subject to 110p 1074 4 deer capability ishm wed es dear 'L 084 availabilityPrices are subject to change 4023 22p "L490 175p aLE.174 325p Owe JAPANESE TRANSISTOR 4024 50p SICT6 90p SPECIFICATION MANUAL without notice 11E2706 325p LOW PROFILE SOCKETS BY TEXAS Operation will teen inexternal 20p 75p This fantastic 4025 ,R? :07 375p '..1''t 22p PROM it required 127601 4026 110p p 7p ' c 150 .' manual Smple supply1551operation. 4027 45p 25p Tunes include: STAR WARS. 10p 20p 28p INTERSIL CHIPS ARE DOWN 471 [IlicrE 4028 75p BEETHOVEN'. 9111 6 51h. JINGLE oeCs on VCBO VEBO IC TJ. IC80 HFE, and more, 4029 80p Due to bulk purchase we are able to offer BELLS. YANKEE DOOOLE. STAR mechanical 4030 50p rnbeatable prices on INTERSIL CHIPS LIQUID CRYSTAL DISPLAY SPANGLED BANNER. CLEMEN- Includes drawings thatillustratecase uiniiits 4031 195p compare our prices below distributors, TINE. GOO SAVE THE QUEEN. 0 595p styles and sizing of each pa. 4033 145p ,CL7106CPL High Contrast Ratio e' a8.8 1 SOLE RIO WESTMINSTER 4 Meeting Street, Appledore, Hr. 4035 104p ,r1.7107CPL 695p DESCENDING SHOP 295p Wide Viewing Angle 4 CHIME and Bideford, North Devon EX39 1RY. 4036 290p CLE10313GCPD OCTAVE CHOU PUS MANY MORE, 1875p 0.5 in. Digit Height Only £4.90 Tel Bideford (02372) 79507. 4037 105p ,CM7216.4121 ULTRA Low Power Consumption ants detailed specs C M7216BIPI 1675p Telex. 8953084 4036 110p LCD106 E11.45 Mid instructions £7.95 an39 290p M7551PA 80p _NEWS: Digest OFFER SECIAL.OF TEPNYEARS (erase tracks 3 & 4, record onto Cassette track 4). A Hi -Lo switch can com- pensateforover -recorded/ Copying distorted masters and the auto recording takes care of the rest. oxebay have announced the There is also a portable seven IF introduction of the firstpor- cassettecopyingversion,con- table machine capable of making sistingofthethree -cassette three copies at a time. Despite its machine linked to a slave four - name,the3-Kassette-Copieris cassette unit. British made. It costs less than all The 3-Kassette-Copier (E398 other two copies cassette copiers. plus VAT) andthe7-Kassette- Foxebay's copier is compati- Copier(E796 plusVAT)are ble with both half track IEC and available from Foxebay Ltd. 41/43 quarter track Japanese formats. It CharlbertStreet,London NW8 uses thecompatibleC -format 6J N. Project 80 Inscrutable lrhe Project 80 Modular Syn- JOHN'S I thesiserisalive and well! A Japanese number ofreaders, who have ELTON already invested a great deal of JVCareholdingtheirThird time and money inProject 80 TokyoVideoFestivalin 10 years ofEYltoesr; modules, are alittle concerned December this year.In celebra- GREATHIJohn'sTS Great Hits in 5 superb that we do not feature a module tion of this they are holding a in every issue. competition to judge video com- albums beautifully boxed and supplied The modular synthesiser was positions from all over the world. together with a full-sized,full -colour pop art poster. conceived as a series of projects, The prize is an all expenses paid For the Elton fans this is a must! each of which was complete in triptoJapan, a trophyand itself. However, if you build all of 300,000 yen (£699). So if you have them and put them in one box a yen (ouch) to try for it, all you EARLY YEARS: with a keyboard, you end up with need is a video camera, recording Includes: Lady Samantha: Take me to the Pilot: Country a formidable synthesiser. on 1/2" or 4" tape in any format. Comfort: Friends. Occasionally we willmiss The film should be no more than ELTON ROCKS: amonth, but Project 80 will con- 20 minutes in length and black Includes: The Bitch is Back: Crocodile Rock: Pinball Wizard: tinue to the end of its natural life and white or colour programmes Saturday Nights Alright for fighting. span. areequallyacceptable. SINGLES: Includes. Daniel: Lucy in the Sky with Diamonds: Philadel- JVC Super Range phia Freedom: Rocket Man. _ MOODS: JVC havejustrevealedtheir Includes: Sweet Painted Lady: Love Song: High Flying: Bird: feature another JVC technical in- Blues for my Baby and me. new rangeof equipment,in- novation,theElectro-Dynamic cluding three new turntables, four Servo Tonearm. The arm senses CLASSICS: new amplifiers, four tuners, four record eccentricity, warp, etc and Includes: We all fall in love sometimes: Curtains: Love lies receivers and five new metal tape compensatesfortheireffects. Bleeding: Captain Fantastic and the Brown Dirt Cowboy. cassette decks. Tracking force and anti -skating All four of the new AX series forcecanbe adjustedelec- To obtain your boxed Album complete the of amplifiers and two receivers in- tronically with no contact bet- coupon below and sendittogether with £12.50 corporate what JVC describe as 'a ween the arm and other parts of your cheque/P.O. made payable to Mod- including post, remarkableinnovationin the turntable. mags Ltd. Allow 21 days for despatch. packing & V.A.T. amplifier design - the develop- Please send me Elton John Albums ment of Super A amplification'. Therangeofmetaltape JVC claims that this combines low @ £12.50 each incl. post & packaging. cassette decks includes a budget I enclose my cheque/PO No. distortionandhighefficiency. model selling for under £100. You Well, we'll let you know what we can build up one of nine recom- NAME think when we get one to play mended, rack -mounting systems with. from the separates to suit your ADDRESS Two of the new turntables needs and your pocket. Send coupon and cheque/PO to : MODMAGS LIMITED Sales Office (Ref : REC) 1 1 r 145, Charing Cross Road, London WC2H OEE. I I -I 1 1 ETI JULY 1980 13 P0DBUoxC6TOARR SE, HSEenRdTrur orders fir DEPT.E EITI TEL 0920 3182 Di70Visit our Shop at3 Baldock Street, Ware, Herts. TELEX. 817861 AUDIO LEADS BOOKS BY BABANI ANTEX IRONS 1943 15 watt Iron element ceramic fitted with 3 /32" bit 65.12 ' Price E p 12.33 No. Type BOOK NO DESCRIPTION 1947 Replacement element for 1943 iron FM indoor Ribbon Aerial £0.69 1944 Iron coated bit 3/ 32"for 1943 iron E0.1511 107 113 3 5rnrri Jack plug to 3 5rnm Jack plug. Length 15m 0.86 8P6 Engineers & Machinists Ref Tables 0.50 1945 Iron coated bit Ye" for 1943 iron E0.611 1.10 60.58 114 5 pin DIN plug to 3 5mm Jack connected to pins 5P14 2nd Book Transistor Equivs & Subs 1946 Iron coated bit 3/ 16" for 1943 iron 3 & 5 Length 1.5m 0.98 52 Projects Using IC741 (or equiv) 0.95 1948 General purpose 18 watt iron fitted with iron coated bit ESA 2 BP24 E2.22 115 5 pm DIN plug to 3 5mrn Jack connected to pins BP26 Radio Antenna Book Long Distance Rxephon 1952 Replacement element for 1948 iron 1 & 4 Length 1 5m C0.98 & Transmission 0.85 1949 Iron coated bit 3/ 32" for 1948 iron COCIS E0.611 116 Car aerial extension Screened insulated lead BP27 Giant Chart of Radio Electronic Semi -conductor 1958 Iron coated bit V." for 1948 iron E1.44 0.60 E0.68 Fined plug and socket & Logic Symbols 1951Iron coated bit 3/16" for 1948 iron 117 AC mains connecting lead for cassette recorders BP32 Build Metal & Treasure Locators 1.00 1931Highly popular x 25 25 watt quality iron ceramic shafts to and radios 2 metres E0.78 BP34 Practical Repair & Renovation of Colour TVs 1.25 provide near perfect insulation breakdown voltage of 1 500 volts 5 pin DIN phono plug to stereo headphone 1.25 118 BP35 Handbook of IC Audio Preamplifier AC and a leakage current of only 3.5uA and another shaft of Jack socket 0.21 50 Cots use Germ /Silt Zaner Diodes 0.75 stainless steel to ensure strength E6.12 BP36 E2.00 119 2r- 2 pin DIN plugs to stereo Jack socket with BP37 50 Projects using Relays /SCRsiTnacs 1.25 1935 Replacement element for 1931 iron attenuation network for stereo headphones 1.25 1932 Iron coated bit 'A " for 1931 iron E0.158 E 1.04 BP39 50 Field Effect Trans Projects 50.58 Length 0.2m BP40 Digital IC Equivs & Pin Connection 2.50 1933 Iron coated bit 'A" for 1931 iron 120 Car stereo connector Variable geometry plug to Linear IC Equine & Pin Connection 2.75 1934 Iron coated bit 3/32" for 1931 iron £0.58 fit most car cassettes 8 -track cartridge and BP41 1953 SK1 kit contains 15 watt iron with a 3/ 16" bit plus two spare BP43 How to make Walkie Talkies 1.25 combination units Supplied with conned fuse ICC555 Projects (Revised & Enlarged Edition) 1.75 solder. heatonk and a booklet How to solder', in presentation E0.69 BP44 E7.28 power lead and instructions BP45 Protects on Opto-electronics 1.25 display box 123 6 6m Coded Guitar Lead Mono Jack plug to Mono Radio Circuits using ICs 1.35 Jack plug. Black E1.73 BP46 E0.86 BP47 Mobile Discotheque Handbook 1.35 VEROBOARD 124 3 pin DIN plug to 3 pin DIN plug Length I 5m 1.35 E0.86 BP48 Brython.. Projects for Beginners E0.63 125 5 pm DIN plug to 5 pin DIN plug. Length 1 .5rn 1.45 2201 2.5"x5..1 Capper EST( 2211 2.51102.5..15 Capper E0.86 8P49 Popular Electronic Projects £2.39 126 5 pin DIN plug to Tinned open end. Length 1 5m 1.35 2201 2.5"X3.75" .I Capper E051 22123.75"x17"15 Copper BP50 6 LM3900 Projects E0.90 127 5 pin DIN plug to 4 Phono Plugs. Electronic Music & Creative Tape Recording 1.25 22032.5"x17...1 Capper E2.14 1213 3.75"X5'.15 Capper All colour coded. Length 1.5m E1.50 BP5I I (1.79 2205 3.75"x3.75'.I Copper 20.71 2211 3.75.X17.9" Plain 5 pm DIN plug to 5 pin DIN socket Length 1 5m E0.92 BP52 Long Distance Television Reception (TV DX) EOM 128 1.45 2206 3.75"011'..1 Capper E2.76 111113.70"XLV .111.1 For the Enthusiast £8.68 129 5 pm DIN plug to 5 pin DIN plug mirror image 2.25 22074.75"x ii.!'1 Capper 23.61 1219 5'x3.75".1 Raw E 1 .21 BP53 Practical Electronic Calculations & Formulae E0.37 Length 1.5m 8P55 Radio Stations Guide 1.45 2209 1.5" 5 in Net 20.135 2223 2.5-05..151* 130 2 pin DIN plug to 2 pin DIN inline socket. £8792225 5"x3.75".15 Phis E0.56 E0.78 Electronic Security Devices 1.45 2204 3.75" x5" .1 Capper Length 5m 8P56 2664 8P57 How to Build Your Ow) Solid State Oscilloscope 1.50 221025"x5" 15CA sr 131 5 pin DIN plug to 3 pin DIN plug 1 &4 and 3 & 5 1.35 Length 1.5m E0.95 8P58 50 Circuits using 7400 Series ICs E1.13 BP59 Second Book of CMOS IC Projects 1.50 BIB HI-FI ACCESSORIES 132 2 pin DIN plug to 2 pin DIN socket Length 10m 8P60 Practical Construction of Pre -amps / Tone Compact tape head cleaning kit 133 5 pin DIN plug to 2 Phono plugs 1.45 806 J 12.85 Connected pins 3 & 5 Length 1her E0.86 Controls /Filters & Ann 810 23 Tape Editing kit BP6I Beginners Guide to Digital Techniques 0.95 Cassette Tape editing and joining kit E2.711 134 5 pin DIN plug to 2 Phono sockets. 2.25 811 24 E0.78 8P62 Elements of Electronics - Book I Salvage cassette E0.51 Connected pins 3 & 5 Length 23cm 2.25 813 29A £0.71 5 pin DIN socket to 2 Phone plugs. BP63 Elements of Electronics - Book II 814 31 Cassette Head cleaning tape 135 2.25 E0.48 Connected pins 3 & 5 Length 23cm E0.78 13P64 Elements of Electronics - Book III 817 36A Record & Stylus cleaning kit Single IC Projects 1.50 41 8 -track Cartridge tape head cleaner E1.24 136 Coded stereo headphone extension lead BP65 818 E2.85 E2.01 BP66 Beginners Guide to Microprocessors & Computing 1.75 42 Groove Kleen auto metal record cleaner Black Length 6rn 819 E0.92 £0.52 BP67 Counter driver & numeral Display projects 1.75 52A Cassette storage tray (holds 101 178 AC mains lead for calculators etc 826 E3.17 BP68 Choosing & Using your Hi.Fi 1.65 53 Hi-Fi stereo test cassette 827 E2.12 BP69 Electronic Games 1.75 829 60 Chrome finish 'Groove Kleen. (plastic) 8F70 Transistor Radio Fault -Finding Chen 0.50 69 Anti -static HoFr cleaning liquid E0.35 0.75 834 E1.50 BPI60 Coil Design & Construction Manual 838 78 Cassette hand tape winder BP202 Handbook of Integrated Circuits Equivs & Substitutes 1.00 TRANSFORMERS 13P211First Book of Diode Characteristics 5 Equivalents & Substitutes 1.25 WIRE CONNECTORS MINIATURE MAINS Primary 240V 1.00 Secondary Price BP2I 3Electronic Circuits for Model Railways Entirely new range of connectors foe Discrete wire. Uniquely designed No. E1.04 BP215 Shortwave Circuits & Gear for Experimenters & Radio Hams Wrepost is soldered to the P.C. Board. A pre -stripped wire is inserted into 2021 65-0.65 100mA 0.85 9v -0-9v 75mA E1.04 the connector and easily locked by pressing the housing down. The wire 2022 E1.29 8021 7Solid State Power Supply Handbook 0.85 is alternatively removed by lifting the housing. Tin alloy plated contacts '2023 125-0.125 100mA 1 25 MINIATURE MAINS Pnmary 2405 81,221 28 Tested Transistor Projects ensure good as gold performance. 0.95 with two independent secondary windings BP224 50 CMOS IC Projects Price BP226 Build Advanced Short wave receivers 1 20 Housing consists of Thermo plastic ;folksier. No. Type BP227 Beginners Guide to Building Electronic Protects 1 25 1728 Single connector in 2024 MT2130-0-6V 0-6V RMS 61.114 £0.12 inc VAT MT150-012V 0.12V RMS £1.S4 RCC Resistor Colour Code Dec 0.20 red /black or white 2025 1729 Threeway connector black ONLY £0.23 inc. VAT 1 AMP MAINS Primary 240V 1730 Fourway connector Secondary Price £0.28 inc. VAT No. P.&P 45p black ONLY 2026 6V -0-6V 1 amp E2.88 9V.0 -9V 1 amp E2.30 P.M' 45p BRACKETS 2027 P &P 55p 1028 125-0-12V 1 amp E2.99 FUSE HOLDERS AND FUSES 155-0.1551 amp E3.16 1..&P. 66p 2029 P &P 86p R ight-angle mounting brackets. Ideal for mounting. PCB, panels et cetera 2030 30V -0-30V 1 amp E3.97 D eecription No. Price into boxes and cases 506 E0.18 STANDARD MAINS Primary 240V 18SVVG - Mild steel - shortfacehas gleaned hole 6 Sore s 3 7crn long 20mm x 5rnm chasos mountIng leon x 1/4in chassis mounting 507 E0.14 Mulotapped secondary mains transformers available in'hamp. 1 amp lace has 3 7cns diem. hole £0.05 l'Ain car mime type 508 E0.18 and 2 amp current rating Secondary taps are 0-19.25-3340.505 0/NO. 1726 Height 15cm, length 15cm, width I0cm 509 E0.23 Voltages available by use of taps. 7. 8. 10. 14. 15, 17. 19. 25. 31, 0 / NO 1727 Height 25cm. length 15cm, width 10cm £0.07 Panel mounting 20mm Panel mounting 1Sin 510 £0.37 33. 40. 25-0-25V. Price QUICK SLOW 20non No. Rating No. 2031 et amp £3.51 P &I. 86p Type No. Type No. Type P &P 86p 615 Sp 3A 619 Sp 2032 lamp 55.06 150mA 611 7p 1A E4.27 P &P £1 SWITCHES 250mA 612lip 1 5A 616 7p 4A 620 10p 2033 tamp 55OrnA 6136p 2A 617 Sp 5A 621 Sp 618 7p 2035 240V Primary055V @ 800mA 614 Sp 2 5A E7.30 P &P Et Darecnpoon Pries 2A Secondary E0.18 ANTI -SURGE 20non L2P121 me6ature slide 1973 Type No. Type No. 1974 £0.17 Type No. SPECIAL OFFER DPDT standard slide 100mA 622 1A 625 2.5A 628 Toggle switch SPOT 11/2 amp 250V ac 1975 C0.38 629 7042 240V Primary 0.20V @ 2A Secondary By removing 5 turns fc, 150mA 623 2A 626 315A each volt from the secondary winding any voltage up to 20V @ 2A is Toggle switch DPDT 1 amp 250V ac 1976 Co." 1 6A 627 5A 630 1977 E0.68 500mA 624 easily obtainable Ideal for the experimenter Rotary onc41 mains switch All Sp @eels P &P 7160 Push switch - Push to make 1978 £0.16 E1.90 1979 £0.21 QUICK -SLOW 1 Iia in Push switch - Push to break Typo No. Type No. Type No. 634 Price 250mA 631 500mA 632 1300rnA ROCKER SWITCH Colour No. All Sp each RED 1980 E0.35 A range of rocker Type No. Type No. Type No. CASES AND BOXES BLACK 1981 £0.35 641 switches SPST - moulded 1A 635 2 5A 638 4A in high Insulation WHITE 1982 00.35 5A 642 £0.35 1A 637 3A 639 INSTRUMENT CASES. In two sections vinyl covered top and IN% material available in a BLUE 1983 All 7p each choice of colours ideal YELLOW 1984 50.35 murninium bottom front and back LUMINOUS 1985 50.35 ter small apparatus No. Length Width Height Petc 51/2in 2in E1.73 No. Price NUTS AND BOLTS 155 8in Description 156 11 in 6m 3.n E2 92 Miniature SPST toggle 2 amp 2505 ac1958 £0.81 Et 79 E0.86 SA BOLTS - packs of BA threaded cadmium plated screws slotted 157 6in 4% in 1 %in Miniature SPST toggle 2 amp 250V ac 1959 Neese head Supplied in multiples of 50 51/ein 21/2in E1.43 1960 £0.92 158 9in Miniature DPDT toggle 2 amp 250V ac Type No. Moe Types No. Price Miniature DPDT toggle centre off 2 amp tin OBA 839 E1.311 Von 4BA 846 50.37 ALUMINIUM BOXES. Made from bright all. folded construction each 1961 C1.09 250V ac lein OBA 840 E0.88 'Ain 4BA 847 10.29 box complete with half -inch -deep lid and screws 1962 E1.04 Push-bunon SPST 2 amp 250V ac lin 2BA 842 £0.75 tin 6BA 848 £0.46 Push-button SPST 2 amp 250V ac 1963 C1.09 Ain 6BA 849 £0.24 E1.38 eon 2BA 843 £0.52 No. Length Width Height Price Pushbutton DPDT 2 amp 250V an 1964 C0.60 %in 6BA 850 £0.28 Vein 2BA 844 159 51/41n 2Von I 1/2 [0 .85 lin 4BA 845 E0.61 160 4in 4,n 11/2in E0.85 MIDGET WAFER SWITCHES BA NUTS - packs of cadmium plated full nuts in multiples of 50 11on £0.85 Single bank wafer type - suitable for switching at 250V ac 100rnA or No. 161 4in 21/4in Type No. Rios Type Price 4in l' £0.97 150V do in non -reactive loads make.beforebreak contactsThese 857 C0.35 162 5Win OBA 855 E0.113 4BA 4in 21/2.n £0 .87 swItches have a spindle 0 25 in dia and 30 indexing 858 E0.211 163 26A 856 £0.88 6BA 164 Sin 2in 1,n E0.60 Rica B A WASHERS - flat cadmium plated plain stamped washers supplied 165 7m 5in 21/2in E1.43 Deffeelption No. E1.83 1965 E0.55 in multiples of 50 166 3,n I pole 12 way Type No. Price Type No. Pries 167 tin 4in 2,n E1.113 6 way 1966 £0.55 2 pole E0.1111 4BA 861 £0.14 4 way 1967 £0.56 084 859 3 pole 768 860 E0.14 6BA 862 E0.14 a pole 3 way 1968 E0.55 SLOPE from aluminium boxes with black vinyl base and odes & SOLDER TAGS -. Hot tinned supplied in multiples of 50 aluminium back. top & front - strong construction easily accessible Price Type No. Price Typo No. Price MICRO SWITCHES No. 169 21/4.n 51kin 21/on 12in 31/2,n 8in E5.45 OBA 851 00.44 4BA 853 E0.25 Plastic button gives simple Ipole change 854 [0.25 168 1ken 7'n 16in 4' 11,n E8.21 over action Rating 10 amp 250V ac E0.29 28A 852 E0.32 6BA Just quote your Access or Barclaycardnumber All prices include VAT Add 50p post per order - aee1.111M Bi-Pak at above address C111,0 Teams Cash with order, cheques, POs, payable to 11=1111 Access and Barclaycard also accepted No 3887006 GIRO A ETI JULY 1980 14 NEWS ETI NEXT MONTH ON SALE JULY 4th 100W MOSFET Amplifier Yet another in the long line of top line audio projects from ETI. Next month we give you a 100 + 100W power amp with bargraph output display, separate PSUs for each channel and a brilliant sound that puts this unit at the very top end of audio today. You will find it costs a lot less than you think to build, too. Electromagnetic Pulse Effect. Never heard of it eh? Most people haven't - yet EMP could be the deciding fac- tor in a nations fight for survival during nuclear attack. With the international situation steadily worsening around us, the facts ETI has turned up about Britain's susceptibility to EMP are very, very disturbing and make mandatory reading for anyone concerned with keeping civilisation alive in the age of the Bomb! As an indication of the situation, did you know that in 1958 a small warhead test in the Johnstone Islands produced power systems failure in Hawaii, SOME 1000 KM FROM THE EXPLOSION, due to EMP? (The British Isles are approx. 800 km in length). Video Today-And Tomorrow Next month ETI takes a detailed look at the expanding world of home video and offers a buyers guide to inform the intending purchaser. In addition we have a look at the next 12 months from Richard Dean (editor - TV and Home Video) - probably the leading writer in the field today. Circuits Appetiser How many times have you glanced at book titles all neatly aligned on a shelf and wondered just how interesting they really are? Well, as of next month maybe we can help. "110 Timer Circuits for the Home Constructor" has just been released by Newnes and ETI is publishing a chapter from it next month. Circuits galore and full details of this very nifty litttle volume. Itis hoped that more books will receive this treatment in the future. Projects, Projects, Projects, Projects. In addition to that truly amazing MOSFET AMPLIFIER we have a further four constructional projects for you next month. There is an excellent VCA module .which fits in with Project 80 if you're following it. Also we give full details of an ULTRASONIC BURGLAR ALARM which could ensure than any visitors you get are at least invited. Two test gear "quickies" are featured in the shape of a LINEAR CAPACITANCE METER with good accuracy and easy construction and a very versatile LOGIC PROBE to allow you to hunt out those missing bits. With all this how can you possibly not buy ETI next month? Articles mentioned herein are in an advanced state of preparation, however, circumstances may dictate charges to the final contents. ETI JULY 1980 15 B.K. ELECTRONICS A SOUND CHOICE * PROMPT DELIVERY * PRICES INCLUDE V.A.T. * AMPLE STOCKS A PERSONAL SERVICE FROM A SMALL EXPANDING COMPANY STEREO CASSETTE TAPE DECK ASSEMBLY. Comprising of a top panel assembly and tape mechanism coupled to a record /play back printed board assem- bly. For horizontal installation into cabinet or console of own choice. Brand new, ready built and tested. Features: Pause control, auto stop, 3 digit tape counter, illuminated twin VU meters with in- dividual level controls, twin mic, input sockets AC erase system, LED record indicator. (Separate power amplifier re- quired.) Input Sensitivity: 6 MV (with GEC AM/FM STEREO TUNER Tape Sensitivity: Output - typically level control set at max). Input Imped- AMPLIFIER CHASSIS. Originally 150 mV. Input - 300 mV for rated ance: 47 k0hms. Output Level: To both designed for installation into a music output. Disc Sensitivity: 100mV (cer- left and right hand channels 150 MV. centre. Supplied as two separate built amic cartridge). Radio: FM (VHF). Output Impedance: < 10k. Signal to and tested units which are easily wired 87.5MHz - 108MHz. Long wave noise ratio: 45 dB nominal. Power together. Note: Circuit diagram and 145kHz - 108kHz. Medium wave. Supply Requirements: 12V AC at interconnecting wiring diagrams sup- 520kHz - 1620kHz. Short wave. 300M /A. Connections: All connections plied. Rotary Controls: Tuning, on /off 5.8MHz - 16MHz. Size: Tuner - to the unit are via a wander lead termin- volume, balance, treble, bass. Push- 23Ain x 15in x71/2in approx. Power ated with a nine pin plug (socket pro- button controls: Mono, Tape, Disc., amplifier - 2in x 71/2in x 41/2in approx. vided). Dimensions: Top panel - 111/2in AFC, FM (VHF), LW, MW, SW. Power 240V AC operation. Supplied complete x 61/2in. Mechanism fits through a cut out Output: 7 watts RMS per channel, at with fuses, knobs and pushbuttons, and 53/ain x 101/2in. Clearance required under better than 2% THD into 8 ohms. 10 LED stereo beacon indicator. Price top panel 21/4in. Supplied complete with watts speech and music. Frequency £21.50 plus £2.50 postage and pack- circuit diagram etc. Price £30.50 plus Response: 60Hz-20kHz within ± 3dB. ing. £2.50 postage and packing. JVC TURNTABLE. JVC Turntable supplied complete with an Audio Tech - nice AT10 stereo magnetic cartridge. * "S" shaped tone arm. * Belt driven. * Full size 12in platter. * Precision calibrated counterbalance weight (0-3 grms.) * Anti -skate (bias) device. Nylon thread weight. * Damped cueing lever. * 240V AC operation, (50Hz). * Cut-out template supplied. SCOTT AM/FM STEREO TUNER MODEL 516. This Scott tuner is one Size - 123/4in x 153A in (approx). of the top American makes and is offered at a very realistic price. Features: * Price £29 plus £2.50 postage and FM tuning range 87.5 to 108 MZ *AM tuning range 535 to 1605 kHz * packing. Usable FM sensitivity 6.2dBF 2.2 yV * 300 ohm & 75 ohm Aerial inputs for FM * Signal strength tuning meter * Stereo beacon indicator * Ferrite aerial DE -SOLDERING PUMP This de -soldering pump made to a for AM * Mute switch. Size: Height 5in, Width 141/2in, Depth 1 2in. Silver very exacting specification is ideal front panel. Black body. Modern stacking format. Price £40.50 plus £2.50 for the removal of small com- ponents from printed circuit boards. postage and packing. etc. Comes complete with spare PIEZO ELECTRIC TWEETERS - MOTOROLA PTFE tip. £5.30 post free. Join the Piezo revolution. The low dynamic mass (no voice coil) of a Piezo tweeter produces an improved transient response with a lower distortionlevel than ordinary dynamic tweeters. As a crossover is not required these units can be added to existing speaker systems of up to 100 watts (more if 2 put in series). BSR P163 BELT DRIVE TURN- Type 'A' 3M round with removable TABLE. This famous B S.R. turntable wire mesh. Ideal for bookshelf hi-fi is ideal for disco/hi-fi use and is offered speakers. Price £3.80 each. at a special price of £22 plus £2.50 Type 'W 31/2in super horn. For general postage and packing. Suitable stereo purpose speakers disco and PA sys- magnetic cartridge type TTC /J2203. tems, etc. Price £4.80 each. Price E4 post free. (Also available Type 'C' 2in x 5in wide dispersion separately.) horn. For hi-fi systems and quality disco etc. Price £6.20 each. Type '0' 2in x 6in wide dispersion horn. Frequency response extending down to mid -range (2000 c /s) suitable LOUDSPEAKER for hi-fi systems and quality disco. Price High quality full range 8" loudspeaker. £9 each. 10 watts RMS. 80H M. Rolled surround Post and Packing, all types, 15p each with aluminium certre dome. (or SAE for Piezo leaflets). Price £3.50 each + 75p Postage and Type 'A' Type 'C' Type D' Packing. B.K. ELECTRONICS 37 Whitehouse Meadows, Eastwood, Leigh -on -Sea, Essex SS95TY * SAE for current lists. *Official orders welcome. * All prices include VAT. * Mail order only. *All items packed(where applicable) in special energy absorbing PU foam. Callers welcome by prior appointment, please phone0702-527572. 16 ETI JULY 1980 FEATURE FILTER DESIGN Following up his supplementary efforts last month, Tim Orr tackles the subject of Active Filters in thesame explanitory manner. The frequency response plot of a first order low pass filter 2/r RC (Fig.1)reveals several important features. The break - Fig.4. Second order unity 0 gain Sallen and Key low frequency Fc, is defined as the point at which the output WHERE d IS THE DAMPING FACTOR signal is attenuated by 3 dB. The curve then approximates to 0 IS THE OFACTOR TOUT pass filter. VIN R a -6 dB/octave roll off slope. By using a straight line approxi- mation it is easy to calculate attenuations caused by the filter. For example, an 8 kHz sinewave filtered by a 1 kHz first order lowpass filter will be attenuated 18 dB, a reduction in level of FOR A BUTTERWORTH (FLATTEST AMPLITUDE) almost one tenth. The calculation is simple; 8 kHz is 3 octaves RESPONSE, d 1.414,0. 0.707 above 1kHz. The filter attenuates at 6 dB per octave, there- fore the final attenuation is 3 x 6 = 18 dB. To increase the roll off slope, the filter order must be increased, figure 2. When constructing high order filters, it is necessary to assemble them out of smaller filter sections each DC PATH BUTTERWORTH TO GROUND Fe = having different Q factors. A high order filter constructed d 1.414 from sections all having the same Q factor will have a very ROLLOFF -12d8/OCTAVE 'unabrupt' frequency response curve, which is generally not what is required. Fig.5a. Second order low pass filter, 1 kHz. FC -3dB POINT VIN 101( 1131"R 10k 10k TRUE RESPONSE CURVE NOTE THERE MUST V1,01 BE A DC PATH TO 741 0 STRAIGHT LINE GROUND APPROXIMATION 7n95 -6dB/OCTAVE ROLL OFF SCOPE BUTTERWORTH Fe lkHz d(SECOND ORDER STAGE) = 1.0 ROLLOFF-.18dB/OCTAVE 025F 0.5F Fig.5b. Third order low pass filter, 1 kHz. LOG FREQUENCY -1111. Fig.1. Frequency response of a first order low pass filter. L TOUT FC 10 0 10k VIN 10k C'jVVVAA.A/114471 ]n22 T 18 ROLL OFF SLOPE FILTER BUTTERWORTH ORDER NO X8dB/OCTAVE Fc IkHz dIF FIST STAGE) 1.848 OS CORD STAGE) 0.765 ROLLOFF-24dB/OCTAVE Fig.5c. Fourth order low pass filter, 1 kHz. A simple first order filter (Fig.3) merely requires a resis- IF 8F tor, a capacitor and a voltage follower. A second order filter LOG FREQUENCY -4111. (Fig.4) requires two RC networks. This circuit has a 'flattest amplitude' response (when it has a Q of 0.7) and is often Fig.2. Filter roll -off slopes. As n increases so does the roll -off. referred to as a Butterworth response. The response may be modified by altering the Q factor, but in all the following VIN examples aButterworth responsehas been chosen. This VOUT design is known as a 'unity gain Sallen and Key' filter. The Q NEEDS A DC PATH factor is deteremined by the ratio of the two timing capaci- TO GROUND 17777 tors. This often leads to a circuit design which employs non - OP AMP IS USED AS preferred capacitor values as can be seen in the three filters AN IMPEDENCE BUFFER by a process known as scaling. For instance, if the required 2r RC break frequency is 5 kHz, then the resistors, or the capacitors C IN FARADS Ft IN OHMS Ft IN Hz in the filter should be reduced by a factor of five. If say the Fig.3. Simple first order low pass filter. filter in figure 5a had to be redesigned to operate at 250 Hz, ETI JULY 1980 17 then the required component changes would be to change the 10k resistors to 40k. Active filters generally employ op amps and so care should be taken so as not to operate them near to their bandwidth limit, which would cause the filter response VOUT to be degraded. A 741, for instance, should not be used for 0 frequencies above 50 kHz. Figure 6 shows the effect of varying Q in a low pass filter. Generally, the response that is wanted is the 'flattest NEEDS A DC amplitude' curve. A fourth order filter (Fig.5c) is constructed PATH TO GROUND from a low Q and high Q filter. The overall response of this FOR C. USE SIEMENS B32560 TYPES 2n RC filter is seen in figure 7. Note that the flattest amplitude curve COMPONENT TOLERENCE 5% (A) is made up out of the product of curves B and C. The peak ROLLOFF SLOPE -24dB/OCTAVE in the high Q curve (C) is flattened out by the droop of the Fig.8c. Fourth order low pass filter, 1 kHz. low Q curve (B). The problem of having different and unpreferred capaci- 8kHz SINEWAVE; MOST OF THE HARMONICS tor values is greatly reduced by using an 'equal component' ARE REMOVED BY THE FILTER design, figure 8a,b,c. The Q factors are controlled by the gain SAMPLE of the op amp and so the capacitor values are all the same. V` CK 8kHz SQUAREWAka Note that these filters provide a voltage gain which is in fact 4TH ORDER LOWPASS Fc 10kH SAMPL V_QUI dB AN ADC DATA VIN 0 0 INPUT HOLDD OUTPUT 3 dB BEST 0 LAY (BESSELI LOW 0 FLATTEST AMPLITUDE 'BUTTERWORTH/ ANTIALIASING FILTER FAST ROLLOFF 0.0.7 ICHEBYCHEV/ HIGH 0 Fig.9. Use of a low pass filter in an ADC system. F, LOG FREQUENCY Fig.6. Frequency response versus Q factor. VOUT) VININ n=1 SLOPE = +648/OCTAVE n=2 " +12d13/ " n=3 " +18dB/ n=4 " +24dB/" n=5 " +3048/ " Fc Fe LOG FREQUENCY -3dB POINT) LOG FREQUENCY A. B Fig.10. Frequency response of different orders of high pass filter. Fig.7. Combining high and low Q factors. Fc 1- 2(r RC d = 1 WHERE d IS THE DAMPING FACTOR 0 IS THE 0 FACTOR FOR A BUTTERWORTH (FLATTEST AMPLITUDE) RESPONSE, d = 1.414 AND CI = 0.707 Fig.11. Unity gain Sallen and Key high pass filter. 2T RC COMPONENT TOLERENCE = 10% d = 1.414 ROLLOFF SLOPE= -12dB/OCTAVE ROLLOFF+12dB/OCTAVE Fig.8a. Second order low pass filter, 1 kHz. Fig.12a. Second order Butterworth 1 kHz high pass filter. VIN 15n 27/ RC COMPONENT TOLERENCE = 10% ROLLOFF SLOPE= -18dB/OCTAVE d=1.00 (SECOND ORDER STAGE) ROL LOF F = +18dB/OCTAVE Fig.8b. Third order low pass filter, 1 kHz. Fig.12b. Third order Butterworth 1 kHz high pass filter. 18 ETI JULY 1980 FEATURE: Active Filters di FIRST STAGE) = 1.848 dISECOND STAGE) = 0.765 (VOUTId ROLLOFF = +244B/OCTAVE VIM 6dB/ OCTAVE SLOPE FL Fe FU LOG FREQUENCY FC = CENTRE FREQUENCY FU-FL= BANDWIDTH IF BW1 Fig.12c. fourth order Butterworth 1 kHz high pass filter. FU = UPPER -3(111 POINT 0 = FC FL = LOWER -3d8 POINT FBW EQUAL COMPONENT HIGHPASS Fig.14. Band pass response (single pole). COMPONENT TOLERENCE- 10% ROLLOFF- +12dB/OCTAVE Fig.13a. Second order Butterworth 1 kHz high pass filter. Fig.15. Single pole multiple feedback bank pass filter. 70k6 VIN RA EQUAL COMPONENT HIGHPASS 39k 39k Fc = 1 2/7 C DiAx8B) VOUT = 'h.s:RB/ C VIN 15n VOUT C C GAIN = 15n 15n 130k6 C RA RB Fe 0 GAIN 15n 10k6 10k6 1kHz 0.5 x 0.5 15n 5k305 21k22 1kHz 1.0 x 2.0 15n 2k652 42k44 1kHz 2.0 x 8.0 Fc = 15n 1k326 84k88 1kHz 4.0 x32.0 2c CR COMPONENT TOLERENCE = 10% ROLLOFF = +18dB/OCTAVE Fig.16. Multiple feedback filter selection chart. Fig.13b. Third order Butterworth 1 kHz high pass filter. the product of the DC gains of each amplifier. Frequency scaling can be performed by modifying the R and/or the C components. Capacitors generally are available in E6 or E12 values, whereas resistors can be obtained in the E24 series, and soitis usually much easier to scale the R components, keeping them within the range 1k to 100k. Low pass filters find many uses in audio processing and are often used in data acquisition systems (Fig.9). The high pass filter (Fig.10) is exactly complementary in operation to the low pass device. The unity gain Sallen and Key structure is seen in figure 11 with calculated valuesfor second, third and fourth order filtersin figure 12a,h,c. Also there are calculated values for 'equal component' realizations in .figure 13a,b,c. Fc 2r CR The band pass response is defined in figure 14. This can COMPONENT TOLERENCE = 5% ROLLOFF- +24dB/OCTAVE be realized with a single op amp circuit, the multiple feedback band pass filter, figure 15. Calculated values are seer), in the Fig.1 3c. Fourth order Butterworth 1 kHz high pass filter. chart of figure 16. The maximum Q should be kept below a ETI JULY 1980 19 FEATURE: Active Filters value of 20 at 1 kHz, otherwise the filter may become unstable VIN 10k 10k 10k 10k and oscillate. Frequency scaling may be performed by multi- plying the R or the C components with a constant. High Q, high frequency operationisnot possible with this design because the op amp runs out of bandwidth. The state variable filter (Fig.17) overcomes this problem by using the bandwidth of three op amps. Q factors of several hundred at 1 kHz are obtainable with this circuit.Italso produces four outputs; high, low, band pass and notch, making it a very versatile design. The frequency may be scaled by altering the R or the C components and also the Q factor is separately programmable and is invariant with frequnecy. The all pass filter (Fig.18) has a flat frequency response, which in (vOUT. VIN (VOUT - - ) dB VIN FC LOG FREQUENCY LOG FREQUENCY Fc Fc =1.-- . BANDPASS 2,r RC (V OUT( )dB VIN Fig.19. Notch filter using all pass sections. Fc LOG FREQUENCY AUDIO SWEEP FILTER GENERATOR UNDER IN TEST OUT Low PASS OUTPUT // SWEEP RAMP X XY OANCIPASS OUTPUT OSCILLOSCOPE IGHPASS OUTPUT NOTCH OUTPUT Fig.17. State variable filter. HIN,.. -.../ Illill:\I (VOUT IN FC LOG FREQUENCY 0 PHASE Fig.20. Testing filter design with 90' anoscilloscope.'Scopetraces from points A and B are shown 180' left (A above, B below). FC LOG FREQUENCY itself is of no use at all. However, it does suffer a 180° phase shiftas a function of frequency. By cascading two stages 10k 10k (Fig.19)itis possible to obtain a 180° phase shift at the frequency Fc. This phase shifted signal when mixed with the original will give a notch response due to the cancellation of the two signals. Testing active filtersis very easy if you have a swept sinewave generator and an XY oscilloscope (Fig.20). The frequency response appears as a linear amplitude versus log frequency display. It is generally possible to sweep five times a second, which gives an almost continuous display and allows you to see immediately the effect of any changes that you Fig.18. All pass filter. make to the filter. ETI 20 ETI JULY 1980 4330NEW .r=, al 190c 'N/014,wE A FUTURECross our palms with silver and see the tuture UsingguesstimateHISTORYguarded our very secret of ownwhat of timeunfold. themight ET!machine, happenBeware project a -ofteam,closely this imitations. is we This is no the future. dispatchedbrought a backteam storiesof reporters of a world to 1999. where They World everyIllustrated future historian.in full colour,War Find III isETI out history 1999 what and is tomorrow a robots must forare causing real holds for you problems. now! Sales Office (Specials), Modmags Ltd, Plus 30p postageSend and your packing. cheque/P.O.145 Charing to Cross Road,London, WC2H OEE Thar il-ocieiheNbA,1a.rwri,fal14- dle,. ye- N1/41T MITRAD MITRAD QUARTZ L.C.D.s AT THEIR BEST! MITRAD GENT'S CHRONO ALARM GENT'S MEMORY GENT'S QUARTZ ANALOGUE FRONT BUTTON CALENDAR ALARM CHRONO A truly superb Brand new 1980 style. LATEST TECHNOLOGY! timepiece with extreme Basic working modes of Constant display of hours, accuracy. A choice of chronograph. 24 -hour mins, secs, weekday and two colours on this out- alarm and dual time zone. snooze alarm indication. standing watch are Constant display of hours, A further two optional available, blue or white. mins, secs and weekday display modes are avail- The calendar in the indication with am/pm, able, one being the calen- watch can be set to give 12 and Al flags. Date dar and month, which can a readout in either indication. The chrono be increased or decreased French or English with runs to 1/10th sec. with to give the appropriate date indication being the1 /10th's running month of the year. A 1/ automatic. along the bottom of the 100th sec chrono with An infinitely adjust- watch. It has a twelve split and lap mode facil- ablestainless -steel hour capacity. The 24 - itiesis built into the strap is built in as part of hour alarm system is watch. A 24 -hour alarm the watch. actuated for a full 60 with a 10 minute snooze The watch is fitted seconds. Dual timing function is also standard with a long -life battery facilities give the watch to the watch. A further and comes with the added touch of com- feature is the back -light luminous markings to pactness. Back -light, and fully adjustable stain- aid night-time vision. closely woven adjustable less steel strap. stainless steel strap ONLY £15.50 VALUE AT £19.95 YES ONLY £19.95 GENT'S ALARM CHRONO GENT'S FOUR -BUTTON THINKING OF BUYING 12/24 CYCLE ALARM LM40 A really superb watch and module. It can be A NEW DIGITAL WATCH- set as a 12- or 24 -hour watch with hours, mins, THEN CONSULT A very compact and secs,am /pm and sleek -looking GENT'S weekday indication Alarm Watch. always on display. A OUR Constant display of unique calendar is built Hours, Mins. and Secs., into the watch. You can FREE FULL -COLOUR have month followed by of Month, Date and date or date followed by Weekday. month, it's entirely up CATALOGUE A very effective alarm is to you. A 24 -hour alarm built in which can be set can be set to any time FIRST within a 24 -hour within a 24 -hour period, and is activated period. for 60 seconds. The chronograph TEL. OR WRITE Back Light and a closely has a 12 -hour capacity woven adjustable and runs at 1/ 10's. stainless -steel strap fin- Split and lap mode FOR YOUR COPY ish the watch off. facilities are available. less steel strap finish the Battery hatch, watch off with impec- ONLY £10.25 mineral glass, long -life cable looks (0536) 522024 battery and a closely woven adjustable stain- ONLY £16.50 GENT'S CHRONOGRAPH LADIES' DRESS WATCH LADIES' SUGARCOATED Another superb ladies watch with that ex- Probablythebest tremely popular sugar looking chrono on the An extremely popular frosted finish. Links can market. Constant dis- ladies 5 -function watch. easily be removed from 'play of hours, mins, Finished in gold. the strap and the clasp secs with am/pm indi- has a spring mechanism Constant display of built in to give a com- cation. Also month, Hours and Mins. with date and weekday indi- fortable fitting. Con- Month and Date being stant display of hours cation. 1/ 100th and available. 1/10th sec with split and mins, with month, and lap mode facilities. Auto -Calendar date, secs, auto calen- Back -light, closely Back Light and a closely dar and back -light. woven adjustable stain- woven adjustable strap less steel strap. £10.50 £10.50 SPECIAL £8.95 MITRAD WHERE RELIABILITY, STYLE AND ELEGANCEREALLY COUNT MITRAD ETI JULY 1980 22 MITRAD ..._...... _ MITRAD QUARTZ L.C.D.s AT THEIR BEST MITRAD GENT'S MELODY ALARM CHRONO DUAL ZEON DIGITAL ANALOGUEALARM TIME * EXCLUSIVE* We are proud to be able to offer This watch is super slim. Only you this scoop purchase. One of 7mm thick, but has 5 independent the finest pieces of modern tech - working modes. (1) Normal watch. nology. Hours, Mins., Secs., A.M./P.M. and mode square indication. The The analogue section can be set as weekday can be set in any of three a conventional hand watch and is different languages, French, totally independent of the L.C.D. English and German. section. (2) Countdown Alarm: Presettable The digital part of the watch has to 24 hours, with the musical tune the following functions: playing for 1 minute. (3) Ordinary 1. Constant display of .Hours, alarm which can be set within a Mins. and Seconds. 24 -hour period and lasting for 60 11 re $-, . 2. Optional Display of Date, seconds. Ue 1. Month and Weekday. *some (2) Dual timing facilities. Pd..41 3. A unique alarm system, - _.... (4) Chronograph: This runs to a which can be set to any - 1/100s. Freeze and split and lap time within 24 hours, and _- mode facilities are standard. is actuated for a full 40 This watch is finished in 3 micron seconds. A five-minute gold and comes with a closed snooze is also available. strap. The watch is finished off with a Back Light. Backlight and an infinitely adjust- able stainless -steel strap. BUY NOW SPECIALLY PRICED AT £14.95 AT £34.95 GENT'S CHRONOGRAPH SOLAR ALARM GENT'S MELODY MULTI -CHIME ALARM The slimmest Chrono Solar Alarm CHRONO in the World. Only 7mm thick. This watch has a genuine solar Latest technology! Con - panel. You can take the battery out stant display of hours, mins and secs, week - and the watch will still function as day, date and month normal. Battery hatch. Mineral with mode and chime glass. indication display. The Constant display of Hours, Mins. musical alarm once and Secs. with Date Flag. Optional actuated plays the tune Oh Suzanna . Twofurther display of Hours, Mins. and Date. "-alarm systems The alarm can be set to any time are incorporated in this within a 24 -hour period and is outstandingwatch (i) / actuated for a full 60 seconds. 24 -hour alarm,(ii) I t , count -down alarm. The The chrono runs to a 1 / 10th Sec. watch can be set to with a maximum capacity of 24 chime on every full hours. Lap Time and Freeze Facil- hour. A 1 / 100th sec ities are available. chrono is standard to the watch. Can be Dual timing facilities are readily switched off. Mineral available. glass face. The watch Back Light.Fully adjustable also has a battery hatch stainless -steel strap. backlight and infinitely adj stainless This watch is available in gold or steelstustablerap. silver. OFFERED AT £19.95 VALUE AT £19.95 MITRAD THE UNRIVALLED RANGE MITRAD We are able yet again to offer you the above watches plus a * FULL COLOUR CATALOGUE NOW AVAILABLE * complete quartz watch range. All at unrivalled prices. Just look M Write or phone for your free copy. Trade lists on at the following points: I (i) 48 -hour despatch guaranteed on both retail, and trade application. orders. T Earn E.E.Es selling watches to all your friends. P/P per (ii) Full instructions and 12 month manufacturer's guaran- tee. R item 85p which includes insurance. Cheques or P.O.s (iii) Our own free back-up service. made payable to Mitrad and sent to (Dept. ETI), 58 (iv) 10 -day full money refund if not completely satisfied A Windmill Avenue, Kettering, Northants, NN 1 6 8PA. (v) Free felt presentation case with each watch. D Telephone (0536) 522024 ETI JULY 1980 23 A HISTORY OF SPACECRAFT Ian Graham takes a well illustrated look at Spacecraft past and present and discovers just how far we've come in the twenty three since Sputnik. n April 12th 1961, a charred ball weighing over He could make independent decisions on, for example, 10,000 lbs lay in a field near the village of Smelo- course corrections based on information on position, 0vaka. Inside lay Yuri Gagarin, the first man to orbit thrust, etc from his on -board computer. In addition, the Earth and begin Man's adventure in space. Gagarin's whereas most of the Mercury systems were carried inside flight marked the culmination of a research programme the pressurised compartment with the astronaut, many going right back to the first artificial satellite, Sputnik 1. of the Gemini systems were removed to a separate in- Less than a month after Sputnik 1 proved the orbital strument module. The astronaut benefited by gaining a equationscorrect,Sputnik 2 carriedthefirstlive more spacious cabin and the system became more flexi- passenger into orbit (apart from stowaway bacteria on- ble, allowing the astronaut to work outside the craft on board Sputnik 1). The first 'cosmonaut' was a dog called any defective instrument. Gemini 5, an eight day flight, Laika. proved that men could work in space without any America boldly went where only one man had gone adverse effects for the duration of a moon -landing mis- before, when, barely a month after Gagarin, Alan sion. Shepard made a fifteen minutes sub -orbital hop to a Rendezvous and docking manoeuvres were practiced height of 116 miles. In February 1962 a silver -suited John between two manned Gemini craft and between Gemini Glenn wedged himself into the cramped confines of his and the unmanned Lockheed Agena target vehicle. Mercury 6 capsule and made the first three orbits of the Gemini 6 should have rendezvoused with an Agena but American experience in space. By then, however, Russia when the Agena failedit used Gemini 7 instead. The had established a commanding lead. Herman Titov had craft manoeuvred to within 2m of each other. Gemini 8 already spent more than a day orbiting the Earth in achieved the first docking, but the operation nearly end- Vostok 2. The list of Russian firsts continued - first dou- ed in disaster. Shortly after docking, a jammed open ble flight, first woman in space, first three-man craft, first thruster rocket started the couplet tumbling faster and space -walk, etc. The six Vostok flights (from April 1961 faster. The crew, Neil Armstrong and David Scott, broke to June 1963) made 259 orbits, in comparison with a free from the target vehicle and ended the mission two grand total of 34 orbits for the six Mercury flights from days earlier than planned - survivors of the first major May 1961 to May 1963. emergency in space. Gemini 11carried out the first computer -controlled re-entry. Human Satellite Gemini gave astronauts invaluable experience in long duration flight and the rendezvous and docking manoeuvres necessary for an Apollo -type moon mission and for future space station operations. In less than two years there were a staggering ten Gemini flights. In the same time Russia flew only one mission - Voshkod 2. (Voshkod 1 was the first three man spacecraft. It flew four years before the first Apollo. Voshkod 2 carried a crew of only two). It achieved yet another first for Russia - Alexei Leonov's space -walk. It was thefirst time a man had left his craft and orbited the Earth as a human satellite, albeit still tethered to his craft. Three months later Ed White spent 21 minutes outside his Gemini 4 spacecraft for America's first space -walk. Gemini 3 carried the first computer into space. Although it was glossed over at the time, largely over- shadowed by the impact of Leonov's space -walk, it was an important development in manned spaceflight. The astronaut was no longer apassenger carrying out predetermined routines or commands from the ground. 24 FEATURE Before flight a Mercury astronaut's pressure suit was thoroughly tested. The first American astronaut to make a space -walk - Ed White in orbit around Mother Earth. of wiring and equipment checking procedures were also Apollo reviewed. The next stage in America's successful space pro- Nearly two years after the fire,the Apollo pro- gramme, now well ahead of Russia's, was the flight gramme was resumed. Apollo 7 successfully tested the testing of the Apollo moon -landing systems and pro- hardware in Earth orbit for eleven days in October 1968. cedures. A Saturn 1lifted the first Apollo Commmand Only two months later NASA reached for the moon. Module into Earth orbit in May 1964. The first Apollo Apollo 8 was the first manned craft to be launched by crew (Virgil Grissom, Roger Chaffee and Ed White) climb- the giant Saturn 5, necessary for the circumlunar mis- ed aboard Apollo 204 for a countdown rehearsal on sion. You may remember Commander Borman's reading January 27th, 1967 and the Command Module hatch was of a passage from Genesis against the backdrop of bolted down. A fire started unseen, somewhere below another world on Christmas morning, 1968. Borman, Grissom's feet and spread to nylon netting, fastenings Lovell and Anders could not have landed on the moon if and insulation material. In the 100% oxygen atmosphere they'd wanted to - they did not carry a Lunar Module. it took only 15 seconds from Chaffee's first warning for Apollo 9, the first manned mission with a Lunar the fire to burn through to the outer shell of the Module, remained in Earth orbit rehearsing rendezvous spacecraft. All three astronauts were dead before the and docking manoeuvres with the LEM (Lunar Excursion hatch could be opened. Module). While Schweickart was standing on the LEM The Apollo programme was immediately suspended. porch he took the memorable photographs of Scott's A quick release mechanism was developed for the ac- head and shoulders out of the CM access hatch. Apollo cess hatch. Although pure oxygen continued to be used 10 combined the experience gained from Apollo 8 and 9. in space, ground operations were carried out with the taking the LEM to within 15 kms of the moon's surface. safer60/40oxygen/nitrogenatmosphere(gradually changed to 100% oxygen after launch by the en- Tranquillity Base vironmental control system). Less flammable materials Approximately one million people were at Cape were used in the cabin. Where non-metallic materials Canaveral on July 16th 1969 to see Apollo 11 blast off for had to be used, they were positioned so as to behave as a the moon. The television audience was around 500 fire break. The design of electrical equipment, location million. After a trouble -free flight, Armstrong and Aldrin sepaiated their Lunar Module from Collins' Command Module and began their descent. Armstrong interrupted the automatic landing sequence and flew the LEM manually when he saw boulders ahead, making it im- possible to land. He finally touched down with only 2% of his fuel left. I've met many, many people (not all space nuts like me) who sat up all night to watch the fuzzy image of Armstrong descending the LEM ladder and stepping off the landing pad on to the dusty surface of another world at 3.56 am on July 21st, 1969. Aldrin joined him and together they loped around the surface placing scientific instruments and collecting samples. On their return to Earththeastronautsput onBiologicalInsulation Garments and were transferred to the Mobile Quaran- tine Facility to isolate any bacteria which they may have brought back from the moon. The Mercury capsule was just large enough to carry one astronaut. By comparison Gemini was a deluxe model. 25 .p121==. -WM c : it,Dr Strike A Light Apollos 12 and 13 were more eventful than the first moon landing. Apollo 12 was struck by lightning at take- off. Fortunately, neither the spacecraft nor the Saturn 5 launch vehicle were damaged. When the Apollo 13 Com- mand, Service and Lunar Modules were more than 200,000 miles from Earth on their way to the moon, the astronauts felt a jolt and saw power and oxygen readings rapidly fall on their control panel. The moon -landing was abandoned. To conserve fuel it was decided to let the spacecraft swing round the moon and return to Earth. The crew moved into the Lunar Module, now aptly nicknamed the 'lifeboat'. Systems were powered down - the only way that the craft could be kept operational long enough for the return to Earth. Reduced power meant a cold, dimly lit cabin. The LEM air conditioner could not cope with the extra volume of both CM and docking tunnel. To keep carbon dioxide down to a safe level, the crew improvised an air conditioner from materials on board. When the Service Module was discarded just before re-entry, the crew saw for the first time the extent of the damage. One panel (4m x 1.8m) had been blown away completely, exposing a tangle of pipes and tanks. It was later found that heater switches had welded closed caus- ing an oxygen tank to overheat and explode. It wasn't known if the explosion had damaged the CM's heat shield. However, re-entry went as planned and the crew of Apollo 13, launched at 13.13 (Houston time) on April 13th, returned safely to Earth. In 1972, four flights later, the programme was brought to a close with Apollo 17, the last of three missions intended to devote more energy to Apollo's scientific potential. Despite six moon landings and the return of over 380 Kg of rock samples, the origin of the moon is still not conclusively proven. Meanwhile in the USSR Apollo 10's Saturn S stands on the launch pad atop its, mammoth transporter. Meanwhile In The USSR Like Apollo, the Soviet Soyuz programme had its set- backs. The test flight of Soyuz 1 seems to have been cut short. After re-entry, the parachutes failed to open pro- perly and the spacecraft crashed to Earth, killing the one-man crew (Vladimir Komarov). Further flights achieved the first docking of two man- ned craft and the first welding in space. Soyuz 11 (June Edwin Alden deploys be Apollo 11 Bola wind experiment. 26 FEATURE: Spacecraft 1971) spent 23 days docked with Salyut 1. The flight went well until re-entry, when contact with the crew was lost. On opening the access hatch after a normal re-entry, the three man crew was found to be dead. The craft had suf- fered rapid depressurisation in the upper atmosphere. From then on the crew wore spacesuits (during re-entry at least) instead of light overalls and flying helmets. The additional life support gear carried meant that the crew had to be reduced from three to two. The Soyuz programme continued, successfully carry- ing out astronomical,Earth resources, EVA (space- walking) and hardware experiments. The first post -launch abort occurred several minutes after what would have been Soyuz 18 lifted off. When the third stage began to go astray, the spacecraft was automatically detached from the launcher and brought down. The next flight (Soyuz 18) prepared the way for the joint US/USSR Apollo/Soyuz link -up. The Apollo/Soyuz Test Project (ASTP) was agreed on as early as 1972, with a planned launch date of July 15th 1975. Both craft did, in fact, take off on July 15th 1975 and docked for a total of 48 hours. Minor problems in- cluded failure of the Soyuz TV system. The huge televi- sion audience had to be content with pictures of Soyuz taken fromApollo.Stafford became thefirstUS astronaut to fly in a Russian Spacecraft. Secret And Wet Soyuz 22 achieved the dubious honour of being, it is believed, the first manned spy satellite. Its unusual orbit took it over a major NATO exercise. Soyuz 23 achieved yet another first - the first Soviet splashdown. During its descent high winds pushed the craft off course and in- to a lake. The crew were unhurt. Stations In Space In the early to mid seventies, both the Soviet and American space programmes moved into their second generation. The hugely expensive one-shot all or nothing flight gave way to the space station. Once again Russia led the way with Salyut 1 (April 1971). The first few years of the programme were beset with technical problems with both the Salyut space stations and the Soyuz crew transporters, but Soviet persistence had paid off by 1975. The Soyuz 18 crew set up a new Soviet duration record of almost 64 days on -board Salyut 4. Unlike Skylab, there appear to be two distinct types The Russian end of the ApollolSoyuz Test Project - Soyuz, still clamped down to the launch pad. The Soyuz/Apollo spacecraft cluster with the newly designed docking module. 111110.- 27 of Salyut craft. One performs a civilian role, similar to The first captive flight of America's Space Shuttle on the back of a Skylab, but the other is part of a separate military pro- NASA 747. gramme. crews make more rapid recovery after their returnto Earth. Health problems amounted to minor skin infec- Skylab tions and eye trouble. In May 1973 Skylab 1 lifted off, launch vibration be- Results from the first few years of space station ing so great as to seriously damage the craft. The operation will themselves take years to analyse. The meteoroid/thermal shield had been torn away complete- Skylab crews brought back over 40,000 pictures of the ly, turning the workshop interior into an orbiting oven. Earth's surface and over 180,000 frames of film of the The debris from the shield had also ripped off one of the Sun. They also carried out melting, welding and brazing solar panels, giving the spacecraft its familiar lop -sided experiments. One of the Earth Resources experiments appearance. identified a possible deposit of copper in Nevada. It may The laboratory was only made habitable by the in- be worth several billions of dollars - more than the cost stallation, by the Skylab 2 crew, of a makeshift sun -shade of the entire space programme to date. over the workshop. Planes In Space Life Out There The most exciting development so far in space hard- Astronauts complained of stuffiness and congestion ware is that of the Space Shuttle - a plane capable of of the inner ear for as long as twelve weeks. Red blood being launched with the aid of strap -on boosters, flying cell production was disturbed for about nine weeks. on to orbit and returning to Earth, landing like a conven- Hygiene and waste management seemed to constitute tional aircraft. themostannoyingproblems.Urinewasspilled. Although the Commander andPilot could take Astronauts found if they missed a meal they would ex- perienceflu -likesymptoms. Heavy exercise helped A cut -away model of the Salyut space station with Soyuz 11. FEATURE: Spacecraft The shape of things to come - the mile -long 'Palomino' spacecraft ponements to the first launch, which is now not expected featured in Walt Disney's 'The Black Hole'. until at least November 1980. manual control, the Space Shuttle is such a complex fly- ing machine that it is usually flown with the aid of com- The Competition America may appear to be way ahead of the Soviet After take -off the two boosters fall away and are Union, but there is already news of a Soviet Space Shut- recovered from the ocean to be used again. The huge ex- tle. So far very little information has been released. ternal tank, whose fuel powers the Orbiter's three main Known as the Raketoplan (Rocket Plane),it measures engines almost to orbit, is discarded and breaks up in the 60m long (probably including the launcher) and 8m atmosphere. Once in orbit, 44 tiny rocket motors posi- across with three main engines. A prototype has already tion the Shuttle accurately. been test flown, dropped from a Tu-95 bomber. With the cargo doors open, satellites can be launch- edorcollectedforrepairby usingthe Remote Coming Soon Manipulator System - a remotely controlled arm made What does the future hold? The Space Shuttle is the by Spar Aerospace in Canada. first spacecraft to offer the possibility of carrying into or- A variety of materials protect the craft from the enor- bit raw materials of prefabricated elements from which mous temperatures of re-entry. The nose of the Orbiter larger structures can be constructed. Film buffs may -reaches over 1400°C. Normally the crew will not inter- recall the Space Shuttle approaching the spinning wheel rupt the completely automatic landing sequence. After station in Stanley Kubrick's film of Arthur C Clarke's landing, the Orbiter is serviced and repositioned on the '2001:A Space Odyssey'. Which of the current rash of launch pad for its next flight. space westerns will prove as prophetic as 2001 is sure to Technical problems have caused a serious of post - be - 'The Black Hole' perhaps, withits spaceship modelled on Brighton pier, or Star Wars, with its World Table 1. A comparison of manned spacecraft to date. War I dog fights in space? MERCURY GEMINI APOLLO SKYLABSHUTTLE VOSTOKVOSHKODSOYUZ SALYUT LAUNCH WEIGHT (kg) 1935 3792 5558 90265 68000 2400 5320 6000 18700 BASE DIAMETER (m) 1.89 3.05 3.90 6.58 2.3 2.63 4.1 LENGTH (m) 2.90 5.60 3.48 36.12 37 2.3 10.63 22 WORK VOLUME (m3) 1.558 5.97 361.4 71.5 9 100 . 10.06 WINGSPAN (m) . 23.7 E ET! JULY 1980 29 No more slaving over hot soldering iron the NASCOM-2 MICRO- KITS Nascom 1is now supplied BUILT! COMPUTER tun Britain's biggest small system is available fully from constructed for you to slot into y6ur own housing FREE 16k for the ridiculously low price of £140 plus VAT (kit eggjg RAM Board price still only E125 plus VAT). )New improved RAM B r emormer,asefs "sielisseeemess MIIINIIMEDIVIM.11111 nascom-I - .... 12" x 8" PCB carrying 5LSI MOS packages, 16 1K MOS memory packages and 33 TTL packages. There ison -boardinterfaceforUHF orun- modulated video and cassette or teletype. only £335 The 4K memory block is assigned to the operating + VAT system, video display and Eprom IMMEDIATE option socket, leaving a 1K user RAM. DELIVERY WM* The MPU is the standard 780A 8 bit. This will run at 4 Mhz but Z80 which is capable of executing 158 is selected between 2/4/ Mhz. instructions including On -board, addressable memory. 2K ell 8080 code. 2K Monitor - Nas-sys 1. 1K Video RAM Microprocessor board' (Nascom 2) (MK 4118). 1K work space /User 4MHz Z80 CPU, TV or Video + 1200 baud Kansas City + Serial RS 232 printer RAM NASCOM PRODUCT LIST + VAT Interfaces; Keyboard; 128 character ASCII plus I( 0 board kit less I/O chips 45.00 (MK 4118) (8K Microsoft Basic) 128 Graphics in 2x2K ROM; free 1.6 -way UART + BAUD rate generator + crystal for I/O board (MK3600ROM) (8K Static RAM / parallel port; 8k BASIC; NASSYSoperating 16.00 2708E). monitor £280 builtandtested. CTC - MK3882 multiple interrupt driven Microprocessors280A, 8 bit CPU This will run at clock generator for I/O board 8.25 4MHz but is selectable between 24 MHz This CPU has P/I0 - MK3881 + interconnect fort/ now been generally accepted as the most powerful 8 bit Firmware &MOS ICs board 8.50 processor on the market. Zeap Assembler (4, 1K X 8 EPROMS) £50 P/10 interconnect only (for I/O board) 3.80 INTERFACE Nas Pen text editor (2. 1K X8 EPROMS) £30 Econographics kit for additional 128 char- Keyboard New expanded 57 key Licon solid state acters (N1 only) 30.00 keyboard especially builtfor Nascom. Uses standard 2708/2716 Programmer suitable for Nascom. monitor controlled, decoding. Floppy disc system N1 and N2 under NAS-SYS 20.95 + VAT T.V.The Iv peak to peak signal can drive a monitor Double sided, double density 51/4in disc giving Nascom 19" rack mounting card frame directly and is also fed to the on -board modulator to drive 280K bytes formatted, including controller for NI and N2 32.50 the domestic T V Nas-DA disassembler 3 EPROM for Nas- board / PSU /Housing and interconnects. £480. sys I 1.0. On -board UART (Int. 64021 which provides serial 37.50 handling for the on -board cassette interface or the Controller board £127.50. Second Disc £240. MK36271 8K BASIC in 8K x 8 ROM 40.00 RS232/20mA teletype interface. CP /M £80. Naspen VS in 2 EPROM 30.00 The cassette interface is Kansas City standard at either Nas-sys monitor in 2 EPROM 25.00 300 or 1200 baud. There is a link option on the NASBUG T2 1 X EPROM 12.50 NASCOM-2 for 2400 Baud System80housing Nasbug T4 2 x EPROM 25.00 The RS232 and 20mA loop connector will interface High strength GRP moulding Tiny Basic 2 x EPROM 25.00 directly into any standard teletype Accepts 12x 8 Nascom 2, CPU board. four 8 x 8 Super Tiny Basic 3 x EPROM 37.50 The input and output sides of the UART are indepen- expansion boards £85 Indframe racking. Super Tiny Basic upgrade 1x EPROM 12.50 dontly switchable between any of the options - Tape Software motherboard. is possible to have input on the cassette and output interconnects and ZEAP 1.2 tape and documentation for Ni 30.00 printer ZEAP 2 tape and documentation for PIO There is also a totally uncommitted Parallel0 Expansion Boards' (in kit form) Nas-sys 30.00 MK 38811 giving 16 programmableI r0 lines These 16K RAM £127.50 32K RAM £175 8K BASIC tape and documentation for Ni 15.00 are addressable as 2x 8 bit ports with complete 48K RAM £220 MEMORIES Discounts 10% for 4, 15% for 8, handshake controls. High Resolution Programmable Graphics £90 20% for 16 Documentation Full construction article is provided Colour Board Kit £140 MK3880 (Z80) for Ni 7.50 for those who buy a kit and an extensive software MK3880-N4 N2 manual is provided for the monitor and Basic High Resolution Colour add on £37.50 MK4116 16K x 1 dynamic RAM 7.50 Basic The Nascom 2 contains afull 8K Microsoft MK4027 4K x I dynamic RAM 2.25 Basic in one Rom chip with additional features like 2102 1K x 1 static RAM 1.00 REEK. DOKE. SET -RESET for simple programming All prices subject to VAT (add 15%) 4118 1 K x 8 static RAM 12.75 Unprogrammed 2708 7.50 Unprogrammed 2716 19.95 IM6402 UART 4.50 21141K x 4 Static RAM' 3.95 COMPUTER KEYBOARDS 8080A 5.25 CENTRONICS QUICK PRINTER OUR LIST PRICE PRICE E459.00 0195.80 TASA 56 key touch sensitive keyboard. All ASCII + VAT characters including control keysParallel output with INCL. VAT strobe. Shift lock. Keys coded in 3 colours to indicate function 18 V DC at 35 mA. 15" x 6.25" x 0.385" thick Black resin encapsulated. E49.50 + VAT PLAIN PAPER Fully built and Star Devices Mk III 71 key touch sensitive keyboard. EXCLUSIVETOHENRY'S housed in a With numeric. pad. All ASCII characters including 50% OFFMAKER'S PRICE PRINTER stylish enclosure control keys Auto key repeat. Parallel output with for: Software selectable 20, 40 and 80 for just £325 plus VAT Interfaces with all micro strobe. Shift lock with indicator LED Built in 'beeper. TANDY, column using 120mmaluminium- computers with level control. 5 V DC at 300 mA 15" x 7" x ised paper. 1roll supplied. 1.25" Grey case with white keys on blue PET, 150 lines per minute. The Nascom IMP (Impact Matrix Printer) features £48.50 + VAT are NASCOMCentronica parallel data interface for Carter 57 key ASCII keyboard. Conventional keyboard Nascom, Tandy, etc r,0 lines per minor,. 80 characters per line 128 ASCII characters including control keys. Parallel 240 volt mains input. ASCII character set Bi-directional print mg 10 line print buffer .output with strobe. Shift lock* 5V and -12 V DC Paper feed, and on/off select switches Automatic CR LF 96 character ASCII set 1 2" x 5.5" x 1 5" Black keys with white legends 'BELL' signal Weight 10Ibs including upper lower case S El. Accepts £39.34 + VAT. Size: 13" x tor x 41" 81/2" paper (pressure feed) Accepts 91/2" paper FERRANTI - "SIZE 14 x 6 x 3" SLOPING New, boxed and fully guaranteed {tractor feed) Tractor;,-. feed Baud FRONT POST PAID Price £195.00 + VAT rate from 110 --Al signal for 55 Key ASCII Coded in steel case Complete with Plug optional synchron-. and Cable with circuit to convert to T T L levels See COMPUTING TODAY Recommendations IDEALFORWORD PROCESSING In good condition at only £25 -0- VAT. Pi P E2 50 March May issues Microtan65Kit, Inc VAT £79.35 Lower case pack, incl. VAT £10.90 Microtan65Assembled, incl. VAT Chunky Graphics Pack, incl. VAT£7.50 £90.85 20Way Keypad, incl. VAT £11.50 'll'17E1E3E7NTanex (min, con) Kit, incl. VAT£49.45 Mini -mother board, incl. VAT £9.95 COMPUTER SYSTEMS LONDON STOCKISTS Tanex Assembled, incl VAT £60.95 Complete Tangerine range available SEND FOR COMPLETE COMPUTER BROCHURE FREEPOST TO ADDRESS BELOW ADD VAT Your London & National Nascom Distributor. 15'.. TO YOUR HENRy's Export Orders deduct VAT, but add5°.carriage ORDER EXCEPT Computer Nit Division Official Export & Educational Orders welcome WHERE 404 Edgware Road, London W2 1 ED, England I.E.D. Our Telex2622'84Mono Ref.1400Transonics STATED 01-402 6822 30 ETI JULY 1980 Takea step up to your nextComputer! THE CONCEPT compatible and fully supported with applications How many ways are there to build an S100 system? Notsoftware. Both 514" and 8" drives are supported in many, and all expensive.TUSCAN changes all that. double density. Five S100 boards on one single board-just for THE PACKAGE starters. Plus five extra slots for future expansion. TUSCAN is available in kit form or assembled. With What a combination! Z80 and S100 with the several hardware and software options to suit your TRANSAM total package of system and applicationsrequirements and budget. Attractive desk top case also software. available holds 2 x 51/4" Drives. How do we do it? Our prices start at £195 and you can build up in easy stages to a fully CP/M compatible disc based system. Something to taink about! THE HARDWARE TRAINAM The first Z80 single board computer with integral S100 expansion. British designed to the new IEEE (8 BIT) S100 specification, the TUSCAN offers total system NOBODY DOES IT BETTER! flexibility. A flexibility available now. The board holds the equivalent of a Z80 cpu card, Send to Transam Components Ltd,. 12 Chapel Street, London NW1 8k ram, 8k rom video and I/O cards with 5 spare I am interested in the TUSCAN Z80 based single board computer S100 expansion slots and offers a price/performance with S100 expansion and enclose a S.A.E. for further details. ratio which is hard to beat. Just compare our price with a commercial 5100 ten Name slot motherboard with this specification. Address THE SOFTWARE TUSCAN offers the user the choice of system monitor, editor, resident 8k basic, resident Pascal compiler or full Telephone CP/M disk operating system. All options are upwardsL 31 TRANSAM COMPONENTS LTD., 12 CHAPEL STREET, LONDON NW1. TEL: 01-402 8137. TELEX: 444198 ANTI- MATTER Does antimatter really exist or is it a figment of your imagination? Have you an antimatter double in another universe? A.S. Lipson explains. Antimatteris,figuratively speaking, the very stuff of which science fiction is made. Most of us have heard of it somewhere or other, but the most we actually know about it can be summarised in the immortal sentence from a TV series that will remain un-named, 'Ye cannae mix matter with antimatter, Captain. . .'. So what is this stuff? If it's 'antimatter' does it have 'antiweight'? Has it actually been made? Read on ... In 1928, a British physicist, Paul Dirac, had developed an equation which seemed to solve an awful lot of the problems current in physics at the time. (Among these was the predic- tion and explanation of a quantity known as the 'giromagnetic ratio' of the electron - but that is really another story.) There was only one slight snag. In addition to ordinary matter, the equation seemed to be saying something about something rather different -a sort of 'negative energy' particle, previous- ly unknown. Well, to cut a long story short, this eventually led to a theoretical understanding of what became known as 'antimatter'. The only thing left to do was to look for it and in due course antimatter was actually found!(Physicists are e+0 Photon energy = recoil energy of heavy particle + rest mass energy of particles + kinetic energy of particles. Fig.1. In certain conditions, a photon can spontaneously transformitself into an electron and a positron(its equivalentantiparticle).The photon must pass by a heavy particle or nucleus which absorbs most of the photon's excess momentum. 32 ETI JULY 1980 FEATURE ingenious fellows; they have to be to get their grants.) In fact, e- it turned out that antimatter had already been noticed in sub- °- atomicreactions, but had been interpretedas anomalous o results! Doing The Impossible We have said that antimatter was found. It would be more correct to say that antimatter equivalents of sub -atomic par- ticles were found. It all started off with the antimatter equiv- alent of the electron, in fact, and the people involved with its discovery were so excited about it that, instead of just calling 0 it an 'anti -electron', they gave it a special name - the positron. 'hm0v2 (e+) + 1/2m0v2 = hv (photon), It wasn't long before other 'anti -particles' began to be 0 where mo = the particle's rest mass energy discovered. Corresponding to the already known proton and v = its velocity neutron, which exist in the nuclei of atoms, there were an h = Plank's constant 'anti -proton' and 'anti -neutron'. In fact, right through to the v = the photon frequency present day, as more and more sub -atomic particles were dis- e+ Fig.2. When an electron and positron meet, they annihilate one another covered, it has been found that each has, corresponding to it, and produce a photon whose energy (E=hv) equals the combined rest an anti -particle of equal mass (with the exception of a few mass energies of the particles. particles which appear to be their own anti -particles). This was exciting!If every particle known had a corresponding anti- particle, then just as ordinary matter is made up of atoms, Let There Be Light themselves made up of sub -atomic particles,itmight be possible for there to be matter which was in the same way It now becomes apparent why it is so difficult to contain made up of 'anti -atoms', which would themselves be made up antimatter in normal containers; if we tried to do so, the posi- of anti -particles... Antimatter! Fine. There was just one small trons would quickly meet electrons, the anti -protons would problem - anti -matter in any form, even just anti -particles, meet protons and so on. All in all, the antimatter, together isn't very easy to contain. In fact, it would probably be fair with an equal mass of the' container, or whatever else was to say that containing anti -matter is one of the closest things handy, would disappear and a lot of energy would be pro- to 'impossible' that the physicists have cooked up yet. To duced. A lot of energy. According to Einstein's equation understand this, we'll have to go right back to the discovery (which has been very thoroughly tested), even a very small amount of mass, is equivalent to an incredibly large amount of of the positron... energy. If a matchstick could be completely turned to energy, there would be enough produced to keep a 100 watt light bulb burning brightly for several centuries! Disappearing Act So far it looks as though the only likely way of containing So far, we have completely omitted to say exactly what it antimatter would be to hold it in very strong magnetic fields, is that is so special about antimatter. We can find this out most but the technique is far from perfected. Even if we could con- easily by looking at the way the positron - the 'anti -electron' tain it easily, which so far we can't, there would remain the - behaves. Now, the positron had a few ratherinteresting problem of obtaining antimatter in reasonable quantities. It is properties. In every way possible, it seemed to be the exact extremely rare and when it is found, (or made, in high energy opposite of the electron; whereas the latter was negatively particle accelerators) it always consists of sub -atomic particles; charged, the positron was positively charged (hence its name) nothing anything as complicated as 'anti -atoms'. Certainly, and so on. The positron did not have negative mass, though. antimatter has not been made in sufficiently large quantities Negative mass, so far, is still in the realms of science fiction. even to weigh, with the most sensitive instruments available - Antimatter has positive mass, and hence, weight. This was supposing that we could weighit without itreacting with interesting enough as it was, but things only really started to matter and producing enough energy to blow up the balance get going when a positron met an electron. If this happened we were using ... the two particles would disappear into nowhere and a high The rarity of antimatter has presented a problem to physi- energy particle of light, or 'photon' would be created. This cists, who like everything to be symmetrical in the universe; was, in fact, an actual demonstration of the truth of Einstein's there is no apparent reason why there should be more matter equation E = mc2, which says that mass and energy are equiva- than antimatter in the universe and yet antimatter seems to lent. Under the right circumstances (such as meeting anti- be very rare. This has led some people to suggest that, in fact, matter) mass can be turned into energy. When an electron there isjust as much antimatter as matter, but not in this collides with a positron, then the mass in each of them gets galaxy. Perhaps about half of all galaxies are made out of anti- turned into pure energy and this is given off in the form of matter, and half of matter; so, there is just as much of each light photons. Pretty impressive eh? The same thing happens kind of matter and the universe is nicely symmetrical. If this when other particles meet their own anti -particles; they dis- is so, then it is possible that, sometimes, out in space, a large appear and all their mass is turned into energy, which is given quantity of matter might meet a large quantity of antimatter off in the form of photons. The more massive the sub -atomic and the whole lot would disappear, giving off vast quantities particle, the more energy is contained in the photons. When a of energy in the form of radiation. If this happens, our astro- proton and anti -proton meet and 'mutually annihilate', for nomers might see this radiation, and deduce what was going instance, the energy produced is 1836 times as much as that on... It is a fascinating idea. And just think; if there are 'anti - produced when an electron and positron meet, because the galaxies', then maybe some of them carry life. Perhaps, some- proton and anti -proton have masses 1836 times as great as the where, an 'anti -person' is reading a positronics magazine and electron and positron. wondering about the possibility of galaxies made of matter... Ell 33 ETI JULY 1980 OLIVETTI PRINTER & KEYBOARD type Te 300 709 DIL 14 PIN CONVERT THIS UNIT TO A with PUNCH & READER. Upper case ASCII with V24 Interface. 240 OPERATIONAL AMPLIFIERS SUPER BATTERY volt operation. at 8p each CHARGER 100 off 2 5% discount Attractive green ministry quality case with £125 each removable top & bottom plates - heavy MINIATURE KEYBOARD duty power switches -high powered resist - INFRA RED IMAGE Push contacts, marked 0-9 and A -F and 3 ors to control current - good quality centre optional function keys £1.75 ea.P&P 65p mounted Amp Meter - strip of wing nut CONVERTERtype 9606 (CV 144) terminals on front panel which can be used 13/4" diameter. Requires single low current 3KV to 6KV supply. BLUE THERMAL PAPER for connecting leads. Individually boxed. With data 430ft. roll, 81/2" wide ALL THIS FOR £3.50. P&P £2 £12.50each P&P 75p Infra Red Lamps also advertised £2 per roll. P&P £1.75 FOUR UNITS FOR £1 2. Carriage E5. STEPPING STEPPING STEPPING MOTORS STEPPING MOTORS North American Philips. 5 volt 6/12 position with additional where the MOTORS MOTORS 3.3 amp operation. 2 wire. PPS rotor is coils. Device can be used as a tacho. 200 steps. 20 oz./in. torque. Diagram supplied. Will actually work on 5 200 steps - 20 oz./in. torque. 0-200 revs per min. 0-250 used. volts. 12/24 recommended. 12/24 volt input, 4 wire. 120 volt operation, 3 wire. . Tested. £1.50 each P&P 75p or 5 for £5 p&p El 50 £12 eachP&P £1.50 £4 eachP&P £1.50 £16 eachP&P El .50 LARGE QUANTITY OF PHOTOMULTI- MUST CLEAR PLIERS 770R used £120 POLARAD SPECTRUM all with information. British approx. 2" £85 ANALYSER window £2 ea. British approx. 5" window R XS 730/10 used 5" Display. These are supplied with STU 2 £3.50 ea. American approx. 2" window £4 Limited quantity only plug-in .1 to 45 GHZ ea. Special American version by RCA £6 ea. £85 each P&P all photomultipliers £1.50 ea. BC172 5p MC4001 15p 11592 10p BC337 13p 6ZY884V7 10p MC4012 15p TIS93 101. BC327 Bp TRANSISTOR INVERTER KEYBOARD PAD EllY8813V 10P MC4020 75P 2N3704 SP BC251 5P 115V AC. 1.7Amp Input. Switching isat Size 3 x 21/2 x 2" high with1 2 Alma Reed 2N3006 5p 74C20 25p 2N5447 SP BC171A 5p 20KHZ. Output windings from Pot Core. Switches. Blue keys marked in green 0-9 I N4305 5p 74C08 25P 2N5449 SP BFT60 5p Can be rewound to suit own purpose or unit and a star with one blank. BZX79C12 10p 74C10 20p 2N3053 15p 4013 30p BC2128 5P MC4049 35p can be broken for host of components SN76550 5p Circuit supplied. £4 eachP&P Cl IC 7451 10p £1.25 eachP&P E2 or5 for £15P&P £2 REGULATORS - act at 45p each. MC7805; 7812; 7815; 7912; 7915. MC14961. 70p Mk. II 16 pin DIE Socket 10p. 14 pin DIL Socket Sp RXs 770R LED type TIL 209 Red with holder 10p each VERY FEW SLOTTED OPTO SWITCH supplied with data - normally over E2. OUR PRICE 75p each. 940 ROCKER SWITCHES 2 pole c/o - 15p each OF THESE Spring Action TERMINALS - normally over 30p ea. OUR PRICE 15p each TOROIDAL TRANSFORMER 0 -115V -230V Input 13.5V -0 - 13.5V rated 8VA output E1.70 each. P&P 75p PRICE ON Sub.min TRANSFORMER 0-120-240V Input 12V -0-12V rated 4VA Output 75p each P&P 50p. 24V INVERTOR VERSION APPLICATION LED.. SPECIAL GOVT. QUALITY Standard White 1 2p, Standard Yellow 15p; Small White 8p. VGC TANTALUM BEAD' We still have a large quantity of CAPACITORS. 4.7uf MAGNETOS 25V. 10 off £1; 100 off SO SIMPLE -SO SAFE TEST GEAR, OSCILLOSCOPES, Fit a push button CIRCUIT AMP METER 21/2" dia. NEW BOXED £7.50. Scaled 0-60.Basic 75MV SIGNAL GENERATORS ETC, BREAKER. Small. compact, . Originally for 14 cyl-gipsy TEXAS Low Profile 40 pin FSD. Complete with ester - 3 ratings 0.8;1.8 & and they are priced to move. Very adaptable IC Sockets 45p each. nal 60Amp Shunt. E2.50 SMALL TRANS- 0AMP. State which one £4.75 each FORMER. 240V Input. when ordering 75p each. each. P&P C1.50. Callers welcome or write or Better Still PHONE for details. Output 2 windings1 2V & 24V 1 amp. E2 each. Miniature MOTORS 12V with geared wheel (8 teeth lb" dial d1/4q. ,a0EY4 for El. PSI' I 1 50 Size 11/4 x 1/4" dia New 30p es. TRANSFORMERS DIODES MOTOR 12V DC with pulley and integral semiconductor Speed AUTO 240V input 115 V1 Amp output E1.25 each. P&P II 25 All new full spec. devices. IN 3063; BAX 13; Control New E1 ae. 240V input. Soc 6V1 86A 8kw Size21/2x 2 x 2". Good LEDEX ROTARY SOLENOIDS. 115V DC No switch assembly. quality E1.50 se. P&P El IN4148; IS44. 100 off £1.50 - 1,000 off 15p ea. 240V input Bac 12V 0.92A Size 21/2 x 2 x 2" Good quality. DIAMOND H CONTROLS ROTARY SWITCH. Single pole E1.50 ea. P&P El £10. 10 -way Printed Circuit Mount New 10p ea. 240V input 1 2V 100MA Size 60 x 40 x 42mm 50p each. DELAY LINE. 50 nanosecs 3 connections. ground -in -out Size 2 240V input. Soc. 12-0-12V 50MA Size 53 x 45 x 40rnrn El x 716 x 16" New 25p es. n. VARIACS EX -Equipment Good condition 8 Amps E25 ea. PULSE TRANSFORMER. Sub min Size1/2 x 5:16 x1/4" 115V input. S. 5V 250MA Site 111 /6 X 1.5 X 155" 2 foe 20 AMPS E35 ea. Secondary centre tapped New 20p as. 50p. Some 3 phase available Please enquire MOTOR by Inland Motor Corp. DC High TorqueReversible SEMICONDUCTORS1 N4005 - 5p; 154003 - 3p. Usable torque at 5V Max voltage 24V £2.50 ea. P&P E2 At Sp eech. CRYSTALS REMO TV TYPE MULTIPLIER. Two high voltage outputs and 38C147, BC14813, BC157. BC158, BC237. 8E197. 0A90. 19 2KHZ FLAT METAL CASE - 50p each. focus El each. 0A81, BA154 BA243 10 MHZ B7G 50p each. DON'T TAKE CHANCES. Use the proper EHT CABLE. 10p per At 25p each: TIP31, TIP41A, 2N5E96, AF 139. 2TX341 metre or E7.50 per 100 metre/drum. P&P MOTOR by Eastern Air Devices Inc 125V reversible with toothed BY127 10p. 13E181 20p; 80239 49p; 8D241 40p; MA343AT LOUD HAILERS shaft I10 teeth 'A" dial See 21/4 x 2`v" die 75p ea. P&P 11 40p; 130228 50p; BD233 & B0234 Comp Pair 25W - 80p per mnsistorised - hand-held - no leads - standard internal pr. et 50p mech. batteries supplied Howl switch PHOTOGRAPHIC LAMPS. Pearl 230V 500 wattScrew cap 75p ea. Box of 12 E5.50. P&P 11 50 REGULATOR TBA625 8 to 20V in - 5V out 100MA 105 Con. E20 ...ch. P&P f1 MYSTERY IC PACK. Some 40 pin - good mixture - all new 50p eech BF256C 20p. TV AMPLIFIER TBA 120 20p leech. devices 25 ICe for Et. P&P 50p You find out whet they we and Integrated Circuits TRANSFORMERS - Standard Mains input we will buy the information from you. Secondary outputs VACUUM PUMPS - TRAPS. ETC. Send for list. 7453 Sp 74H74 12p 75325 E1 6KV 0 125A C15 a. DECOUPLING CAPACITORS. 0 05m1d 10V. 0.01mfd; 0 1mfd 7451 5p 74H51 7p SNI5E162 4p 3440V 0 66A with matching 4011 Choke £30 the pair 50V, 0.047mfd 250V All values 100 for E1. 7402 12p 74538 10p MC4028 89p 3KV 50MA ES se. 4 Volts 250 Amps E10 ea. E.H.T. CAPACITORS 500pf 8KV 20p each. 7476 20p 74502 12p 7417 14p 18KV 30MA E60. 10 -WAY MULTI COLOUR RIBBON CABLE. New, 40p per 7495 35p 74154 713p 7441 40p 22 5KV 110MA ESO ea.5KV 300MA Et 5. metro. 10 metres for E3. 74122 12p 74CO2 74C86 50p 60KV 0.0273 E150. 12KV 30MA £20. GEC UHF 4 -button tuner E1.50 eech. 74C00 17p 74004 1 74C161 24p MULTI PURPOSE MAINS TRANSFORMER 4 windings each CENTAUR 115V FANS 41/2 X 4 x 11/2" £4.50 ea. 74C74 18p8p winding 0.10-110 I 25 at 48A E15.. EX -USED equipment. tested 80p each. 425V 50112 2 Wire input Output 8 5KV 2 55KVA Could be POTTER & BRUMFIELD TIMER RELAY, 115V AC Heavy MOTOROLA DUAL in Line 6 pin Opto Coupler 30p each. Gold run on 240V at 1/2 rating EIS ea. duty7 pole c' s with 2 second delay Charge R & C for different plate tester version 50p each. STEP DOWN ISOLATING TRANSFORMER Input 220 250V timing 50p eech. EPROMS 2708 E5.50 eech. 50HZ Output 115V 18KVA. BRAND NEW These are very SPEAKERS 21/2" 50 ohm 0 1W New 40p each. TELEPHONES 706 style black or grey £6.50 each. 746 style conservatively rated E20.. RAND DISCHARGE capacitors Bmfd 4kV E5 each. P&P £2 black or grey £7.50 each. Older style black £2.50 each. P&P CAPACITORS BIG INCH Motor.110V AC 3 rpm 50 cycle Very small. 50p El 50 per telephone 2infd 5KV E4 ea. 0 5 mid 10KV E4 ea. each. Honeywell humidity controllers 50p each. 8 mid 2 5KV E4 ea. 0.5 mid 5KV Ea ea. CONTACTORS. Heavy Duly 24V DC 5 make £1 each. THYRISTOR TIMER. Solid State15 secs adjustable (reset/ in CARRIAGE on these units will be charged at cost. GEC UHF VHF 6 -button tuner £2 each. plastic relay case Standard 7 -pin base Series delay 50p each. DIGITAL 24 -HOUR CLOCK with builtin alarm as used .n Braun MINIATURE PC MOUNT SLIDE SWITCH. Single pole 3 -way NFRA RED QUARTZ LAMPS. 230V 620 Watts Size 131/2" x Digital clocksSilent runningLarge illuminated numerals AC 10p each. mains Sue 61/2 x 71/4 x 21/4" ONLY £3.75 each. /s" iliaE1.50. VARIACS. 2 amp Standard 240 Volts E10 each. PEP 12 BRIDGE RECTIFIER. 2 Amp 50p es. 931A PHOTO MULTIPLIER in stainless steel container with ELECTROSTP TIC VOLTMETERS. 7 5KV ES each. P&P El 50 PHOTODIODE DETECTOR 4" fly leads 25p lac window and built in resistor network E2 each. P&P f 1 Other ranges available Please enquire SLIVER CONTROL 500W. Log Single trackComplete with TRIMMERS. Sub min 0 25 to 1 25pf to to 4 5p1 AM PHENOL. 17 -way chassis mount edge connectors 0 1 knob Length 31/2" 25p each. 7 to 45pf All spacing 16p sm. RANCO 250V 18A THERMOSTATS with Control knobs at Op each. IF C Standard MAINS LEAD. Moulded 13 vertical flat pins centre CROWN replacement MOTOR for IBM GOLFBALL TYPEWRITER calibrated 50.200 degree C £2.50 each. offset) 60p ea. 115Volt 50HZ 1350 rpm Ef4.50 ea. P&P E2 FANS. 115V 13 Watts. Size 31/4 x 31/4 X 11/4" BRAND NEW SOLID STATE UHF TUNERS. 30 acs El each. BRAND REX blue wire wraps 30 metres for £1. SMITHS encapsulated transistorised AUDIBLE WARNING [4.50 es. Secondhand £2.50 ea. 5in SOLID RUBBER RINGS II" iliarubberl Keep the kids Pi DEVICES 4V -12V Can be driven from TEL 65p each. MINIMUM ORDER £3 VALUE OF GOODS. MINIMUM P&P E1 - where P&P not stated please use own discretion - excess refunded. CARRIAGE ALL UNITS f5 P&P or CARRIAGE and VAT at 15% on total MUST BE ADDED TO ALL ORDERS. CALLERS VERY WELCOME STRICTLY BETWEEN 9am-fpm and 2-5pm Monday to Saturday inc. BARCLAYCARD (VISA) and ACCESS taken. Official orders welcome. =11111111:11111/111EAL LTA NORWOOD ROAD, READING TELEPHONE NO. READING 669656 (2nd turning left past Reading Technical College in Kings Road then first right - look on right for door withSpoked Wheel AIWatchSPECIAL REPORT MEWS FREE JULY 1980 60p to all readers Don't buya digital watch 1-7)1(14;EITA untilyou L WIT(../J read thisreport SURVEI There are so many digital watcheson the market, with varying functions, that theaverage person is bound to feel somewhat confused. A new survey of the electronic watch industry has been produced to clarify by Trevor Raven. this confusion and to give an unbiased C.Eng. AMBIM. MIERE and objective answer to the many questions that are constantly being raised. Which is the best watch? * How accurate are electronic watches? These four watches arevery * Who makes Seiko's? differentinprice,durability and NE What is the import e between functions. How would you choose brand names? between them? 30E Is solar power wgfth the extra money? Thisunbiasedandobjective * What are the most important reporthelpsyoutomakethis features in a watch? decision and gives you a deeper * When will prices stop falling? insight into the rapidly changing and exciting world of the micro -chip. For your free copy of the report, The survey answers all of these complete and return the coupon to: questions and 'tells you what to look Metac Electronic & Time Centres, for in a quartz watch; how they work; 24 -hour DespatchCentre,FREE- why the prices vary so much; what POST, 47A HighSt.,Daventry, the future holds. Northants. FREE OFFER r 1 Send today for this free technical Name report, plus news of a unique Metac offer to beat all special offers. Address Complete the coupon below and senditFREEPOST (nostamp required) and we will post, Same Day Despatch, the technical report giving you all you need to know about electronic watches and details of our ET17i special offer. L ETI JULY 1980 35 r TRANSFORMERS ...... z..., Panel Meters, Bridge Rectifiers, Power Supply Units 124iIRIL Multimeters - Semi Conductors - Timers - Safebloc .i- 48 Minimum & Sub Miniature 50 VOLT (Pri 220-240V) _____. _) Maii- Sec 0-19-25-33-40-50V Assemble CLO Ref. Nice Ret. Price Itin an evening! SILENT RUNNING amps No.£ P&P Amps No. £ P&P MECHANISM MECHANISM & CASE LARGE ILLUMINATED Volta .85 0- 238 2.55 .65 0.5 102 3.55 inc.assembly instructions NUMERALS 3-3 200 1.00 WITH ALARM 0.6, 0.6 1A IA 212 2.95 70 1.0 103 4.55 104 1.15 9-0-9 100 13 2.25 .65 2.0 7.25 AS USEDINBRALlin 0.9.0.9 330 330 235 2.10.65' 3.0 105 8.55 1.15 DIGITAL CLOCKS 500 500 207 2.70.70 4.0 106 10.80 1.25 0-8-9, 0-8-9 1.45 £ 5.00I £6.99 08-9, 0-8-9 1A 1A 208 3.50.70 6.0 107 15.05 1.65 THREE FOR £13.50 MECHANISMS 10 FOR E39. 100 FOR E300 0-15, 0.15 200 200 236 2.10 65 8.0 118 20.15 020, 0-20 300 300 214 2.70 .85 10.0 119 24.05 2.15 AC MAINS HALF PRICE OFFER 20-12-0-12-20 700PC)221 3.45.85 80 VOLT (Pri: 2.20.240) SIZE 63/4 x 2 Vo x 2 1/4 015-20, 0-15-20 1A 1A 206 4.55 1.00 Sec: 0-24-30-40-48-60 Your receipt is a 2 -year 015-27, 0-15-27 500 500 203 4.00 .85 Ref. Price Amps No. E P&P guarantee 015-27.0-1527 1A IA 204 5.05 1.00 HeimyRty 0.5 124 3.80 .851.0 12 AND/OR 24 VOLT 126 5.55 1.00 Pri' 220-240 Volts HENRY'S RADIO EXPORT 2.0 127 7.50 1.15 DELIVERY Any. Price 3.0 125 11.05 1.25 404 EDGWARE ROAD, INQUEOES 12v 24V Ref. E P&P 4.0 123 12.30 1.45 LONDON W2 lED 01-723 woe FROM STOCK 0.5 0.25 111 2.25 .70 5.0 40 14.10 1.55 1.0 0.5 213 2.70 .85 6.0 120 17.55 1.55 2 1 71 3.20 .85 AUTO TRANSFORMERS 4 2 18 4.00 .85 Input/Output Tapped 0-115-210-240V 5.55 .90 6 3 70 VA Ref. Price 4 108 7.40 1.15 8 No. £ P&P 8.20 1.15 Watts) 10 5 72 20 113 2.60 .85 116 8.80 1.15 12 6 75 64 4.05 .85 17 10.80 1.25 16 8 150 4 5.56 1.00 20 10 115 13.80 1.45 Input/Output Tapped 30 15 187 15.80 1.45 QUALITY REEL TO 0-115-210-220-240V 60 30 226 33.30 1.75 300 53 10.06 1.15 CASSETTE 30 VOLT (Pri, 220-240V) 500 67 10.50 1.45 REEL & CASSETTE TAPE HEADS TAPE POPULAR UNIVERSAL Sec: 0-12-15-20-24-30V 1000 84 19.55 1.55 812-01 E12-09 Price Also 1500/2000/3000VA £1 .89 . MONO PLAYBACK MONO/STEREO ERASE . . 11.85 Ref. AIY1 1130LATING(CentreTapped & B12-02 822-02 Amps No. E P&P £5.87 112 2.80 MONO RECORD/PLAYBACK . E4.02 TWIN HALF TRACK RECORD/PLBK 0.5 8SPri: 120/240V Sec 120/240V C44RPS02 1.0 79 3.55 .85 824-01, VA Re. Price STEREO PLAYBACK 83-39 QUAD OUARTER TRACK REC/PLBK 44.37 2.0 3 5.55 1.00 (Watts) No. E P&P C22ES02 20 1.15 824-02 3.0 6.25 60 149 6.55 1.00 STEREO RECORD/PLAYBACK . . um TWIN HALF TRACK ERASE . . . 84.22 1.15 4.0 21 6.55 100 150 7.55 1.25 B24 -RP 5.0 51 9.55 1.15 151 11.05 1.25 STEREO GLASS FERRITE REC/PLBK [11.82 MAGNETIC TAPE HEADS CATALOGUE 25 PENCE 1.15 200 6.0 117 11.05 250 152 13.25 1.45 AUDIO AND HI FI CATALOGUE ISO PACE FULL COLOURI 50 PENCE 8.0 88 14.30 1.45 350 153 16.25 1.55 10.0 89 16.55 1.45 PLEASE ENCLOSE 1000 156 37.05 3.15 30p PAP WITH ORDER Please add VAT at 15* /a William Street ni NCILITH Barclaycard and Access facilities Herne Bay, Kent THE MONOLITH ELECTRONICS CO. LTD. ALL PRICES available 5/1 CHURCH ST, GREWKERNE, SOMERSET ENGLAND 10460)74321 INCLUDE VAT BAYDISHerne Bay 64586 Trade and Education Welcome TIP30C 70p 4025 25p 4072 25p TRANSISTORS TIP295565p 4026150p 4081 30p TIP305560p CVO 4027 50p 4082 30p ZTX10712p 4028 90p 4085 85p AC127 25p BC547 8p ZTX10812p 4001 25p 4029110p 4093 800 AC128 25p BCY71 180 ZTX10912p 4002 25p 4040110p 4095110p STEVENSON 4042 850 4510 90p AD161 40p BD131 35p ZTX30014p 4006 950 AD162 40p BD132 350 ZTX500150 4007 25p 4046110p 4511 100p BC107 10p BD139 350 2N305325P 4011 30p 4048 60P 4518 90p Electronic Components 4520110p BC108 10p BD140 35p 2N305555p 4013 45p 4049 50p BC109 10p BF X29 25p 2N3702 9P 4015 85p 4050 50p 4527165p BC147 9p 8F)(134 260 2N3703 9p 4016 48p 4052 80p 4528100p AT LAST! OUR NEW 1980/81 CAT- BC178 16P BF Y50 23p 2N3704 9p 4017 80p 4060120p 4532125p ALOGUE IS NOW AVAILABLE. BC182 10p BF Y51 23p 2N381922P 4018 90p 4066 63p 4543170p stows BC182L100 MJ295598p 2N3905 10p 4020110p 4068 25p 4583 80p Our new catalogue is just packed with components 40221000 4069 25p 4585115p It contains 100 illustrated pages detailing over 3000 BC184 10p TIP29C60p 2N5777500 4023 25p 4070 25p line items. These include: BC184L10p DIODES 10p 4024 60p 4071 25p 1 Amplifier modulesConnectors Meters BC212 1N914 4p 1N4148 3p Desoldering tools Ni-cad cells BC212L10p 1N4001 4p 1N4002 5P Books lop Low Profile Breadboards Drills Op -amps 13C214 1N4006 7p 1N5401 14p SKIS BC214L 10p BZY88 series 8p each. Texas En1R411T°6C tS Cabinets Etchingequipment Rams 8 DID 9p 22pin 20p Cables Heatsinks Resistors COTIVr".- LM324 52p MM57160 6500 14pinlip24pin 22P Capacitors IC sockets Switches and LM339 55p NE531 1400 16pin12p 28pin 26P CMOS Knobs Tools utos LM348 1000 NE555 23p 18pin16P 4OpIn 38p much more. Crossovers Mains Transformers Triacs 741 18p LM377 1700 NE556 60p 20pin18p Included with our catalogue you will receive: 747 70p LM378 2300 NE567 120p a reply paid envelope for your first order. 748 40p LM380 80p RC4136 100p a mail order form to facilitate rapid despatch 7106 850p LM381 140m SN76477 230p SWITCHES CA3046 700 LM382 1200 TBA800 80P TOGGLE a 50p discount voucher to be used against mail order CA3080 75p LM386 90p TBA810110p Standard SPST 40p DPDT 55P purchases over E10.00. CA3130 1000 LM387 1200 TDA1022 6300 Miniature SPDT 80p DPDT 900 Available now by post from the address below at a cost of CA3140 60p LM1458 40p TL081 45p Subminiature SPST 65p DPDT 85p LF347 1700 LM1830 1800 TL082 85p SLIDE Standard DPDT 17p. Miniature 16p each. TL084 125p LF351 45p LM3900 600 Push to break 22p. Due to stock and administrative problems over the last few months, LF353 900 LM3909 720 XR2206390P PUSH Push to make 16P. ZN414 80p the quality of our service had suffered considerably. These problems LF356 950 LM3911 1200 7447 74123 50p ZN425E475p 65p have now been resolved and we are confident that we can now offer LM301A 30p LM3914320p 74125 600 LM39153200 744865p the quality of service we had been accostomed to. We wish to convey ! M318 850 747235p 74126 600 747338p 74132 70p our apologies to any customers who have been inconvenienced. Specially designed packs intend. 7400 7474360 74141 95p ed for development work at a 15p ppaS 7401 15p 747540p 74145 90p considerable saving. All prices include VAT. Please add 740215p 747640p 74150 120p 50p carriage on orders below E15. 000 'so. resistors. 10 of each value 4.7ohm to 1 Mohm. 740416p 7483800 74154 1100 Contact our sales office with your 0.125in. 0.2in. a total of 650 resistors. 5300 each. 740638p 7485800 74157 8013 Red TIL209 TIL220 100 Ytw resistors. 10 of each value 4.7ohm to 1 Mohm 740822p 748635p 74164 1200 requirements on 01 -464 5770 Green TIL211 TIL221 16p a total of 650 resistors. 875p each. 7410180 749045p 74165 1200 Yellow TIL213 TIL223 16p'7' Presets. Pack of 5 of each value from 100ohms to 741335p 749255p 74174 100p Clips 3p 3p 1 Megohm. a total of 65 presets.390p each. 741456p 749345p 74175 950 DISPLAYS LED's. Pack containing 10 of each colour LED 742016p 749470p 74190 100p DL704 0.3in CC 130p 0.2 size. Total of 30 Led's clips. 450p each. 7427300 749570p 74191 1000 DL707 0.3in CA 130p j Zeners. Pack of 5 of each value from 2U7 to 33V 743030P 749670p 74192 100p 74196 FND500 0.5in CA 100p A total of 130 zeners. 880p each. 743235p 7412145p 1000 76 College Road, Bromley,Kent BR11DE. ETI JULY 1980 36 FEATURE DESIGNER'S NOTEBOOK In this month's 'Notebook' Ray Marston looks at practical applica- tions of a neat little eight pin National chip, the LM3909 LED flasherIoscillator Acommon and seemingly trivial task often facing the design engineer is that of providing an illumi- CELL ESTIMATED BATTERY LIFE nated (glowing or flashing) indication of the ON UNDER CONTINUOUS OPERATION state of a piece of electronic equipment or the location SIZE of a passive device (fire extinguisher, emergency switch, STANDARD CELLALKALINE CELL etc) in a darkened room. AA 3 MONTHS 6 MONTHS These tasks are obviously easily. solvedifmains 7 MONTHS 15 MONTHS power is readily available, but can present serious pro- D 1.3 YEARS 2.6 YEARS blems when battery powered equipment is concerned. LED indicators typically draw 12 mA or more when il- luminated and can thus place a fairly heavy strain on small supply batteries. LEDs, in any case, drop two or LED more volts under the ON condition and can thus not readily be powered from battery voltages below 3 V or so. 7 6 National Semiconductors provided an ingenious solution to this problem some years ago when they in- LM3909 troduced the eight pin LM3909 LED flasher/oscillator 2 chip. This device acts basically as a low duty cycle (brief ON period, long OFF period) oscillator that provides a ],1 I1V5 voltage -doubled high -current pulse to an external LED. 270u 3V Because of the voltage -doubling facility, the IC can flash Fig.2. Practical 1V5 LED flasher with details of estimated battery life. a LED even when powered from cell voltages down to Nominal flash rate is 1 Hz and typical average drain current is 0.63 mA. 1V1. Because of the low duty cycle facility, the device can provide high pulse currents (up to 100 mA) while still drawing very low mean currents (typically 0.3 to 1.5 mA) The LM3909 and can thus provide months, or even years, of con- The internal circuit of the LM3909, together with tinuous operation from a single 1V5 cell. typical external connections for 1V5 flasher operation, is shown in Fig.1. In this application, the LED receives cur- 68 rent (via the 270 uF capacitor and the internal 12R 2R resistor and Q3) for only about 1% of the time. For the remaining part of each operating cycle all transistors ex- cept Q4 are off. The 20k resistor from Q4's emitter to LED supply common draws only about 50 uA. The 270 uF capacitor is charged through the two 400R resistors con- nected to pin 5 and through the 3k0 resistor connected to pin 4 of the circuit. TransistorsQ1-3remainoffuntilthe270uF capacitor becomes charged to about 1 V. This voltage is determined by the junction drop of Q4, its base -emitter voltage divider and the junction drop of Q1. When the 6k0 voltage at pin 1 becomes a volt more negative than that at pin 5 (the supply positive terminal) Q1 begins to con- FAST RC SLOW RC 3k0 9k0 I duct and then turns Q2 and Q3 on. OUT NC I 3k0 NC RL The LM3909 then supplies a pulse of high current to Vo the LED. The current amplification of Q2 and Q3 is bet- ween 200 and 1000: Q3 can handle over 100 mA and Fig.1. The internal circuit and practical connections of the LM3909 low rapidly pulls pin 2 close to supply common (pin 4). Since voltage LED flasherloscillator IC. The IC outline is also shown. the 270 uF capacitor is charged at this time, its other ....ter- ETI JULY 1980 37 minal at pin 1goes below the supply common; the voltage at the LED is then higher than the battery volt- age; the internal 12R resistor (between pin 5 and 6) limits the LED current to a safe value. Thus, the 270 uF capacitor alternately charges via the 3k0 timing resistor and discharges via the LED and 12R resistor. In some other applications, the short between pins 1 and 8 can be removed, enabling the capacitor to charge through a total of 9k0, with a consequent reduc- tion in duty cycle and mean current consumption. lkO If voltage boosting is not needed (with or without Fig.5. Fast 1V5 blinker. Flash rate is 2.6 Hz and drain current is 1.2 mA. current limit), loads can be hooked directly between pins 2 and 6 or pins 2 and 5 of the IC. shunted by an external 1k0 resistor, thereby reducing the Let's look now at some practical applications. charge time constant of the circuit and causing the flash rate to increase (to 2.6 Hz) and the duty cycle and mean LED Flasherllndicator Circuits current consumption to rise. The circuit gives a more Figure 2 shows the Fig.1 1V5 flasher circuit redrawn noticeable flasher indication than the three earlier cir- in a practical configuration. The circuit gives a brief cuits, but at the expense of 1.2 mA of mean current drain. flash once every second or so and typically draws an If you enjoy experimenting with circuits, you can average current of only 0.63 mA. As you can see from the build the variable rate flasher ofFig.6. The rateis table, this circuit will give from three months to 2.6 years variable from zero to 20 Hz via the 2k7 potentiometer. of continuous operation from a battery, depending on The two external 68R resistors are used to stabilise the the size and type of cell that is used. duty cycle of the circuit and maintain a fairly steady ap- parent brilliance level in the LED as the rate is varied. At:1r LED 7 LM3909 if 1V5 2 4 +100u Fig.3. Minimum power 1V5 flasher. Nominal flash rate is 1.1 Hz and average drain current is 0.32 mA. An even longer life can be obtained from the 'mini- mum power' flasher circuit of Fig.3. This issimilar to the Fig.6. Variable rate flasher. The rate is variable from zero to 20 Hz. one described above, except that the short isremoved from between pins 1 and 8, causing the capacitor to charge via 9k0 of internal IC resistance and so operate with a re- duced duty cycle and reduced mean current consump- tion. The circuit has a typical current drain of 0.32 mA. The Fig.2 and Fig.3 circuits are of particular value as 'indicator'or'locator'beconsforuse onfireex- tinguishers, emergency lanterns,torches, emergency switches, etc. The operating frequencies of these circuits are heavily dependent on supply voltage, asindicated in Fig.4. This circuit is similar to that of Fig.3, except that it is designed for 3 V operation, in which case the timing capacitor value has to be increased by a factor of 2.7 for approximately the same flash rate. Figure 5 shows another variation of the 1V5 flasher circuit.Inthis case the internal timing resistors are Fig.7. High efficiency 'continuous' 1V5 LED indicator. The circuit pro- vides a steady but dim illumination by pulsing the LED at 2 kHz. Drain LED 01 current is 4 mA. The Fig.7 circuit is designed to give apparently con- 7 6 tinuous illumination of the LED when powered from a LM3909 1V5 cell. The circuit in fact acts as a 2 kHz square wave 3V generator, the two external 68R resistors being used to 2 approximately equalise the on and off times of the generator. The circuit gives a dim LED Illumination and 270u has a battery drain of about 4 mA. LED brilliance can be 3V increased, if required by using the alternative connec- Fig.4.Fig.4. 3V 1 Hz flasher consumes an average current of 0.77 mA. tions of Fig.8, but at the expense of 12 mA of battery drain. ETI JULY 1980 38 FEATURE: Designer's Notebook CALCULATORS, SCIENTIFIC *SPECIAL OFFER TEXAS 7159 together with PC100C (Complete as manufacturer's specifications) £285.00 TEXAS/HP Accessories available *TEXAS 7159 (Card prog 960 prog steps of 100 mem) £156.50 *TEXAS 7158 (Key prog 480 steps of 60 mem) £60.00 *TEXAS PC100C (Printing Unit for 7158/159) £140.00 *TEXAS T157 (Key Prog 8 mem. 150 Keystrokes/ 50 Prog Steps) £25.00 For your Timm 7158/69 Calculator ELECTRICAL ENG. MODULE LEISURE (GAMES) MODULE STRUCTURAL ENG. MODULE NOW AVAILABLE R2 68R *TEXAS TI PROGRAMMER (Hexadecimal Oct) £46.50 *TEXAS 7151 /iii (10 mem 32 Prog Steps Stat / Sci) £26.30 TEXAS 7150 LCD (Sci /Stat. 2 Con Mems) f23.00 Fig.8. This 1V5 circuit gives an apparently steady and continuous LED TEXAS T125 LCD (Sci /Stats) £17.00 indication. Battery drain is 12 mA. TEXAS T53 (Sci. 32 Prog Steps-Coa Mem +80 Prog List Applications book) E25.00 Make more of your 68R Texas T158/69 Calculator MATH/UTILITIES MODULE If you write your own programs this library is for you! Most programs in this library are designed to be used either on their own or as subroutines of your programs. Applications range from utility programs such as printer formatting and large-scale plotting to advanced mathematical routines. Module includes: Prompter. Alpha Messages. Printer Fomatting. Superplotter. Sorting. Data Arrays. Data Packing. Prime Factors. Hyperbolic Functions. Gamma/ Factorial. Random Numbers. Normal Distribution. Interpolation. Roots of a Function. Minimax. Romberg Integration. Differentia,' Equations. Discrete Fourier Series. Calculator Status. Variable Arithmetic. Module Check. *TEXAS T158 with Maths/Utilities £90.00 *TEXAS 7159 with Maths/Utilities E186.50 *TEXAS 7158 with Applied Statistics £80.00 *TEXAS 7159 with PC100C & Applied Statistics C305.00 SUMMER SALE *TEXAS 7159 Calculator (complete as manufacturer's spec. master module. charger, etc). PLUS statistics module and extra set of 40 Blank Prog Cards with wallet, etc. ONLY £180 NEW TEXAS T158C* Fig.9. This 6 V flasher operates at about 1 Hz. *Continuous program facility on all 480 Program steps/ 60 mem even when calculator switched off £79.50 *TEXAS 7158C (complete plus Applied Stets. Module) £99.00 *TEXAS 7158C + PC100C £208.00. 1141P33E (8 mem. Pro Sci /Sta) £50.78 *HP32E (Advanced Sci with Statistics) E40.50 *HP67A (K Prog 224 Steps 26 Mem) £188.70 *HP97A (Fully prog with Printer) £384.35 HP41C (the newest calculator from HP) £173.48 HP41C Card Reader /Printer etc. Now in stock £242.00 CASIO FX8000 (10 dig Sci /Sta. Stop Watch /Alarm) £27.73 CASIO FX501 P (Sci. LCD Prog. 128 Steps 11 Mem) £47.50 CASIO FX502P (Sci. LCD Prog 256 Steps. 22 Mem) . £65.00 CASIO Prog Adaptor - permits Progs to be recorded on to standard cassette recorders loi eplay on Casio FX501 P/FX502P at later stage POA LEXICON LANGUAGE TRANSLATOR (With 6 Lang. Module - French / Italian / German / Spanish etc) £128.70 NOW IT'S YOU AGAINST 'COMPUTERS' CHESS CHALLENGER "7-17 levels of game) E76.50 CHESS CHALLENGER "VOICE"If0 Levels - beginner to Master Plus) The strongest Prog yet in this series - twice as fast as the other challengers A microprocessor with 128.000 to 160.000 bits of read only Mem Over 8000 bits of Random Access Mem Teaches opening & end game solutions Plays against itself. Solves book problems etc - and in addition IT SPEAKS Complete with Deluxe playboard, hand carved men with magnetised base plus Deluxe carry case . £170.00 SARGON. The most advanced chess game yet with ad on module availability for other games POA (Our price Inc. FREE rochorgooblo bottory pock) r/FREE - moms. Charger included. LEARNING AIDS TEXAS DATAMAN (Number Games -Table learning etc5. 10 yrs) E18.00 TEXAS SPELLING B (Spelling Games Weal 510 years) £22.50 Fig.10. This LED flasher circuit can be operated from any supply in the TEXAS SPEAK AND SPELL (tor older children 8 13 yearSI E39.95 85-200 V range. IDEAL FOR STUDENTS ALL WITH LCD DISPLAY All of the LED flasher circuits that we've looked at TEXAS T120 (Jun Sc, a- Con Mem/ El 3.00 TEXAS T125 (So /Stat C Mem) E17 00 so fare are intended for operation from 1V5 or 3 V sup- TEXAS T138 (So/Con Mem-Pola ROC Cony Dec Deg cony/ Deg Min Secl £19.95 plies. Most of these designs can in fact be used, in slight- ly modified form, at voltages up to 6 V, as shown by the GOODS FULLY GUARANTEED PRICES EXCLUDE VAT ADD 15 circuit of Fig.9. Note in this case that a 68R resistor is Company, Hospital and Government orders accepted by phone wired in series with the ALED, to limit its drive currents. Barclaycard Visa Access accepted by phone The LM3909 IC has a 6V5 zener built in between pins TEL. 01-455 9823 2 and 4 (not shown in Fig.1). This fact is put to practical EXPORT ORDERS WELCOMED use in the flasher circuit of Fig.10, which ca be powered Air Freight 'Alf Post Delivery from any DC supply in the 85-200 V range. The 100 uF OLiotalmos on rr.guest timing capacitor is connected between pins 4 and 5 in this application. ET! ETI JULY 1980 39 .atrSe tftSo J5TELEPHONE ov000sie." vos LB ELECTRONICS 0. ec. UXBRIDGE 55399 SUPERSAVER 12 IEC mains chassis plug with filter. MEMOREX 661 dual disk drives. PCB OFFERS SUPERSAVER - Ribbon Cable Headers 16 DIL TMS 3128NC Static shift register. 250V 6 amps. Ideal for MPU complete with power supplies and (1A) 100 bit shift register PCB,, £1.50, p&p 25p. users. Equivalent to RS238-429. format electronics (sorry, no data 115mmx94mm containing Jermyn, gold plated, with cover as yet), £350 each inc. of VAT. 45p, p&p 25p SUPERSAVER 13 £2.50, each p&p 30p. (Limited 90491, 6x7496 and 10441. PL259 (UHF) Elbow Connectors. stocks.) Recordacall telephone answering Terrific bargain 85p, p&p 30p. SUPERSAVER 2 50p each, p&p 25p. Suitable cable socket 66p each, machines (GPO line matching (IS) Audio amp PCB (LM380) Tantalum Capacitors 25 volt. 4.7 SUPERSAVER 14 p&p 25p. transformer removed) sold as is 9-18v d.c. output 21/2 watts into 8 uF, 14 for £1.00, p&p 25p. 1 S423 Stud mounting rectifiers. from £2 to £10 depending on ohm with heatsink. 1.25 watt SUPERSAVER 3 440v, 10A, giveaway price, 10 for GIVEAWAY condition. Fitted with very nice 4ohm without heatsink. £1.50 Stepping motors, 40mm dia. £2, p&p 25p. 22 pin low profile dil socket, standard cassette deck. With p&p 25p. 70mm long 5mm shaft (approx), SUPERSAVER 15 gold plated circuit diagrams. SORRY BUT FOR (1C) PCB 215mm x 290mm 12-24V torque 340 GMC. Brand 20K Painton multiturn trimpots, 20p EACH CALLERS ONLY. 12XTMS 3122J (or sim.) Hex new, give away price E2.50, p&p PCB mounting, per box of 14 p&p 25p Terms cash with order (official 32 -bit Shift Reg. + 39 ICs. £2. + 40p. £2.50, p&p 25p orders welcomed from colleges, 50p p&p (limited stocks) SUPERSAVER 4 SUPERSAVER 16 WE STOCK PETS etc). All enquiries s.a.e. please. All HYBRID SYSTEMS DAC 371-8 8 Astec UM 1163E 36 modulator 8K version £599. SAE for the PET prices inclusive of VAT, unless MPU CORNER SORCERER software lists at dis- 2112 (200ns), £3. 2114 (450ns) Bit, Dil packaged, ideal MPU users plus PAL colour PCB (faulty). Few otherwise stated. Postage as with data, £2.95, p&p 25p. only E2.25, p&p 30p. count prices. shown per item. E4.50. We can also offer a 48 -hour repair FOR THE PROFESSIONAL 1702 E2.50. 2708 (400ns) SUPERSAVER 5 service for out of warranty PETs. USER. CP Clare Keyboard £6.25. LM 323K Voltage Regulator, 5volt Telephone for details. PET edge 3A, E4.50, p&p 25p. switches with buttons (blank) 65p 2716 (Single Rail) £19.00. LEDs (Full spec). connector 40 X 04 £1.40 each each p&p 25p. 74125 4 for E1 + p&p 25p. SUPERSAVER 6 TIL209, red 10p. 0.2in, red 12p. p&p 25p. Gould PMA 47/10 015V 3A MK 1002P (dual 128 bit Shift Reg) RS 338-383 Miniature Decade 0.2in. green 28p. 0.2in, yellow IC HOLDERS (Low -profile) Brand new £45 p&p £3.50. Many 311p. Thumbwheel Switch. E1.65, p&p 28p. 8 Dil 12p 14 Dil 15p more in stock but in small LM711CH (Voltage Comparator) 25p. RL54 red Axial lead. 15p. 16 Dil 17p 18 Oil 20p numbers. Please phone for 3O SUPERSAVER 7 P&p on all above 25p. 22 Dii 28p 24 Dil 35p requirements. MM5240 Character Generator + SN74116 Dual 4 Bit !etch 75p, VERNITRON Ceramic filters type Data 2560 Bit (64 x 8 x5) 28 Oil 45p All p&p 35p PLEASE DO NOT ORDER GOODS p&p 25p. FM4 10 7MHz 4513. p&p 25p. FROM OLD ADVERTS. PHONE E3.50, p&p 25p. SN7418 Arithmetic Logic Unit, (All Full Spec) TRANSISTORS, BD236 40p, WE STOCK a vast range of TTL, BEFORE ORDERING 80p, p&p 25p. BC183L 10p, BF195 10p, SGS some 74LS. MINIATURE 2526 Character Generator (64 x 9 CMOS Surplus stocks purchased for SN 74194 4 Bit Register, 50p p&p 2N3055 30p, p&p on all 25p. TOGGLES, etc. cash X 9) £2.95 + data & p&p 25p. 25p. TBA 8105, with data. 85p, 4 -way PSUs. We have a large stock of D TYPE CONNECTORS SN 74198 8 Bit Shift Register. 75p Oil switches, 75p. MC1303 Dual power supplies at very realistic LB ELECTRONICS 15Way: wirewrap plugs only 75p. p&p 25p. Stereo preamp with data, £1.26. prices (callers). 11 HERCIES ROAD 26 Way: ribbon plugs £1.20. SUPERSAVER 8 7inNylon cable ties 100 for HILLINGDON, MIDDLESEX 25 Way: plug (solder) £1.00. BC 108b 8p each or 100 for £1.50. All p&p 25p. RELAYS ITT 700 ohm Single pole UB10 9LS, ENGLAND 25 Way: sockets (solder) E1.00. E7. P&P 25p. NEW SN76477 (Yes, back in All enquiries s.a.e. please 37 Way: pig £1.40. SUPERSAVER 9 stock). Sound Generator IC (Train, changeover, 45p. BANOR reset - 50 Way, slit (wirewrap) £1.65. plane, explosion, laser gun etc.). table double pole changeover 12V New retail premises. now open 4 Digit 7 segment LED Bubble Mon, Thurs Fri, and Sat, 9.30- 50 Way. skt £1.45, p&p 25p. Display, NSA 1540A Ex equip- with data £3.25, p&p 25p. £1. Both p&p 25p. PCB KEYBOARD, 65mm X 6.00. Lunch 1-2.15 weekdays. COVERS ment, 5 for £1, p&p 25p. Closed all day Wednesday. We are SUPERSAVER 10 82mm. 18 key Clickers less Key CIRCUIT BREAKERS 37 Way. 80p. (plastic) p/p 25p. tops, ideal Hexadecimal use 35p, 4450v AC 65v DC 0.5A 50p; ditto situated just off the A40 Opposite 25 Way: 65p. (plastic) p/p 25p. 9 way male /female connector, Master Brewer ELCO 8129, 0.1 inch pitch, gold- p&p 25p. 7A 80p, p&p 25p. DISPLAYS plated PCB mounting, ideal for CAPACITOR SCOOP. 1,600uF ALLEN KEYS, 7/16in 5p; 12 for UXBRIDGE MAN 72 7 seg CC £1.25 p&p 25p. bussing two PCBs together. at 10v, 160uF at 25v. Axial lead. 2 50p, p&p 25p. Superb value, 35p, p&p 25p. dozen for E1 + 25p p&p. ASR33 (with tape punch reader), 55399 B urroughs Panaplex 9 Dig, + skt generally overhauled, £225 inc. of and bezel £1.00, p&p 25p. SUPERSAVER 11 PAPST min -fans 80mm X 80mm LED 3 Digit OIL 55p, p&p 25p. STAR OFFER. Dynamic hand lapprox) 220V 50Hz Brand new VAT. ) All components full microphone 200 ohm with lead £8, p&p El (limited stocks). CALCOMP MODEL 140 8in Disc B ounnar 9 digit tin LED with red Drive fully tested, E195 inc VAT, bean(As used in calculators). and 5 pin plug. £1.26 (unrepeat- Pewec Boxer. As above but 11 5v carriage &cost. MSG + 25p p&p. able) p&p 30p. at £4.50 + £1 p&p. bi:=1* KRAMER & CO PRESENT THE LATEST IN CONSUMER ELECTRONICS '7 LEVEL' Chess Com t a realistic price. Plays black, white or itselfSeven levels BABOON 2.5 MODULAR CHESS SYS- of play from beginner to aspen Does not permit - TEM. Contact us for price Unparalleled illegal moves Castles. Kingsidis Queenside. En strengths through entire game Opening Passant. Plays opening defences such as 0 Book Lzbraty Mate-irstwo problems solved in Sicilian. French, Ruy Lopez, Queens Gambit , two minutes. Seven computer strength declined. Analyses as many as 3,024.000 AA . se 0 SI IS n ii * or VIM ,t IS g IS at levels. Instructional mode features. Plays board postions. Establish your own position I by USCF & BCF Rules. Audio Alen System 1" and watch the computer react Pawn promotion Exclusive rank display and position yard.. 1 sides changeable in Mid -Game. Size Iron Position programming Backspace 121/2 vs x1 inchMains powered. VOICE control Tournament timer Move monitor CHESS CHALLENGER available P 0 A SUPER SYSTEM III LCD display of International symbols for all Battery extra. 0 Position storage memory moves. Plays Mack/white or itself Timed playing strength 0 secs to Halt /hint control Changing sides Alpha- 100 hours. AJI International Chess Rules inc Draw by 3 & 50 move numeric display rule. Move Counter. Set up your own position. Position As recommended by ETI SENSORY CHESS CHALLENGER 8 erification. Illegal moves rejected. Automatic Castling & £270 Major Features En -Passant. Computer does much more. £1 54.98. Rechargeable batteries evadable at special 11 No keys to press. This is the start of a system. To fit your needs optional extras include: price S A E 2) New sensory playing surface automatically tells the computer your Rechargeable Power Pack LCD Chess Board £105.95. Memory Unit to every TO.. store games for up to 1 year. Plus the worlds first Electronic Printer to 3) The playing squares light up to graphice1Iy show you the computer's record moves. SAE for details and prices of accessories next move AS RECOMMENDED By ETI 4)Eight levels of play. .5) Dry cell battery operated, or through the mains using the adaptor supplied SPACE INVADERS Geese Program 6) Quick, easy. position verification feature. r zitsi The ultimate Game Programme with 112 game 7) Analyses as many as 3.024.000 board positions. izz ATARIBASIC PROGRAMMING RtiehtiffItSINI variations including Moving Shields, Zigzag £129 grog Laser Bombs. Fast Laser Bombs, Invisible Invaders and 1 & 2 Player Games! This superb V/ le * Iff IV * tt. f.'Y.!tt.1, cartridge uses the joystick controllers and costs ELMAC 4810 CRT 5MIls scope E120 + V. 0 111 A only E27.50 inc(. VAT plus 50p Post and =..FMGM I Packing Order Now! VAT As recommended by ETI. The best Ito, Atari with space invaders £148 selling 5MHz 4" CRT scope in the UK. Time- s.. ova., rm.., base include swep range - 100 rnsetidiv to I Irm....MR IlitalLe 5 1 y sec /thy in 5 steps 3" else available. E58 = Ot.ii.ctiii m 1.001K -f- VAT 4 111 I.I. I= 41.41,14/1C 73 Free 10.1 Probe Elea 5810 5" CRT (12.5MHs) £181.71-t Orders beingbooked for July delivery £34.50. VAT Vertical axis 1 deflection sensitivity 10mV /div Bandwidth - DC DC 12 5MHz !. (between 3dB points). AC 2Hz 12 5MHz ADVENTURE - Adventure plays like the (between 3dB pants). Rise time 20n sec. Ina., addictive Dungeons and Dragons fantasy role IIIII Attenuator - 12 step - 10mV /thy to 50V / diy playing board game and includes the added ill in1-2-5 sequence calibrated. Time Base - SINCLAIR SC110 (mini scope) E146.20. dimension of video A wicked magician has Sweep range 0.5p sec /div to 0.1 sec /div in 12 PEM 200 E58.20. DM 450 E102.46. stolen an Enchanted Goblet and hidden it steps. calibrated with <5 expansion. Fine DM350 E76.99. ADM 35 E34.50. somewhere in the Kingdom. The object of the i controlVariable between steps includes TB DM 235 E55.130. game is to rescue the Goblet and replace it calibration position iftude the Golden Castle where it belongs - no V easy task. Three deadly dragons and a black bar hinder your quest. but scattered throughout the Kingdom are objects to help you slay the Kramer & Co., Dept. ETI 9, October Place, dragons and outwit the evil magician £22.50 We will match any lower price it competitor plus 50p P&P. London NW4. Tel: 01-203 2473. Telex 888941. has stock. SAE for comprehensive chess Attn: K7. reports on all the above. Vi.. Access. Barclaycard & Company orders accepted Orders by telephone/telex Open Mon -Fri (Sunday by appointment only) ETI JULY 1980 40 SEIKO OFFER SE/KO ALARM CHRONOGRAPH FIRST '3, MG Tu TnFP SP TIME UNDER SELECT 50 Two Super Seikos - offered for the first time in living memory £39.95 for under £50. How do we do it? £49.95 You can say that again. How do ALL INC we do it? ALL INC Let's look at the simple Seiko first - a dependable chronograph with no nonsense operation. At the touch of a button you can select either the things that normal watches do i.e. telling the time or a stopwatch display with the usual split/lap time facility. The next Seiko is a bit clever. It's an alarm chronograph with a locking facility. What does that mean, I hear you say. Buttons are prone to being pushed, especially buttons that reset the watch time. However, with this remarkable wrist piece you can just press the LOCK button and pushing all the other controls suddenly has no effect. Full chronograph and alarm facilities we also featured. SEIKO DOUBLE WATCH OFFER Name Address I enclose a cheque/PO made payable to Modmags Ltd for £ Modmags Ltd., Please send me Seiko ChronographIs) at £39.95 each. Sales Office ( Ref. Seiko Offer),145, Charing Cross Road, Seiko Alarm Chronograph(s) at £49.95 each London WC2H OEE. ETI JULY 1980 41 MORE BIGVALUE FROM YOURTANDYSTORE 1000 OHMS/VOLTS AC/DC 6 -DIGIT MULTITESTER 8 RANGES FREQUENCY Dual FET imput for Handy MUI titester for COUNTER accuracy and minimum home and work -shop. loading. 11.5cm mirrored Counts frequencies Easy -to -read two colour scale. DC volts. 0-1-3- 10- from 100 Hz to over 5cm meter. pin jacks for ail 30- 1C0-303- 1000. DC 45 MHz with 100 mS 8 ranges. Reads AC and current 0-100 a. 0-3-30- gate time. Accuracy is DC volts: 0-15-150- 300 milliamp. Resistance V,1 3 ppm at 25°C or less 1000 DC current; 1) -30 -300 -3k -301C-1 0-150 mA. Resistance: then i-. 30 Mkz on 10 megaohm. 0-100- lk- MHz! Overload - 0-100.000 ohms. 101C- 100K-3 Accuracy: ± 3% full scale protected 1-meg megaohms. Req. 9V input. Sensitivity, 30 on DC ranges. battery. 22-209. ± 4% on AC ranges. mV up to 30 MHz. 1,A-4,04 Complete battery. Req. 9V battery. 22-027. REG. PRICE 22-351. REG PRO': Hi PRICE £29.95 TRANSISTORIZED DIGITAL IC LOGIC PROBE SIGNAL INJECTOR For RF. IF. AF circuits. SIGNAL Maximum accuracy. Easy TRACER pushbutton operation. Needs two "AA- batteries. 22-4033. Spot circuit troubles and check RF. IF and audio ,F, £2.79 signals from aerial to Unique,r,witry makes it a combined level detector. speaker on all audio pulse detector and pulse stretcher. Hi -LED indicates AC/DC CIRCUIT equipment. With 9V logic "1". Lo -LED is logic "0". Pulse LED displays battery, instructions. pulse transitions to 300 nanoseconds, blinks at 3 Hz TESTER 22-010. for high frequency signals (up to 1.5 MHz). Input kira( 1 300 volts impedence: 300K ohms. With 36" power cables. ranges. Safe in live dead 22-300. ircuitsNieocis t.sc "AA' hatter, 22-4034. REG. PRICk£9.95 REG. PRICE£19.95 REALISTIC DX 300 DYNAMIC VARIABLE POWER SUPPLY General coverage receiver. Quartz -synthesised tuning, TRANSISTOR Power project boards. IC's. other low -voltage DC digital frequency readout. 3 -step RF Attenuator. 6 - equipment. Load regulation: less than 450mV at 1 range preselector with LED indicators. SSb and CW CHECKER Imp at 24V DC. Ripple: less then 25mV. Maximum demodulation. Speaker. Code oscillator. Batteries (not Shows current gain and itput current: 1.25 amps. Switchable colour -coded included) or 12V DC. 20-204. electrode open and short leter reads 0-25V. DC and 0-1.25 amps. Three-way circuit. Tests low, medium ,riding posts take wires. banana plugs or dual banana REG,R, or high power PNP or NPN .PS .'/4h 0.75"centres. For 220/240V AC £229.95 nes. Go/no-Go test from 22-9123 -:OmA on power types. REP 22-024. £35.95 £9.95 You save because we design, specifically for or by Tandy at 16 factories around the world. The quality of our manufacture, sell and service. products has been achieved by over 60 years Tandy have over 7,000 stores and dealerships of continuous technological advancement worldwide. Over 2.500 products are made ANDY DEALER Most items also available at Tandy Dealers. Look for this sign in your area. The largest electronics retailer in the world. OVER 170 STORES AND DEALERSHIPS NATIONWIDE.------ 42 ETI JULY 1980 NEWS AUDIOPHILE A small step for an electron, a quantum jump for amplifiers? Being unable to resist the obvious puns, Ron Harris takes a searching look at one of Britains newest amplifier stars. how -time again this month. Spent an editorial hour hope things improved later on. The sounds I heard have sor eight wandering around the hallowed halls of the done much to persuade the average audio man that Cunard Hotel. My annual pilgrimage to the Far East perhaps his idols have clay feet after all. (or London) this - all face the Mecca Bingo Hall and pay One little twenty second burst of a very well record- homage to the gods of high technology. ed opera is the only reason I bother to mention them at Frankly, though, I thought this year's offering a little all. Insipid musical wallpaper and delicate solo flute is below the standard that this event has set itself in the no way demonstrate such a systems capability in a past. Somehow there did not seem to be that charisma, crowded, noisy environment. that indefinable something, that electric charge to pro- If you've got it - flaunt it, don't flute it. pel the visitor from room to room, eyes goggling at the plethora of mind mangling miracles wrought since last he trod these boards Or to put it another way a lot ofit was boring. Quantum Amplification Naturally there were exceptions, but somehow the best demos were given by companies showing established Having started somewhat slowly, Quantum Elec- products. One which particularly caught my ear was the tronics are well on the way to becoming one of Britain's minute A4-14 active loudspeakers, from Audio Pro. mostsuccessfulamplifiermanufacturers.Atthat These have a sub -woofer built in to the enclosures and miserable Hi-fi 80 exhibition their room was one of the are capable of bone bleaching sound levels with a bass few that was continually carpeted with wall to wallpeo- that sounds a lot larger than its 20'x 12 x 10 inches. The ple, which did detract considerably from the demonstra- sound is simply stunning and would appeal to a very tion, admittedly. This sort of thing need not concern the large number of people,I think. Audiophile reader, however, as I'd already arranged fora Also making an impressive debut was the new J BE review model. loudspeaker, with its unusual 'four -box' approach. The Listeningisinfinitely more pleasant sat sitting at bass drivers are separately housed and would win no home, in front of the speakers you know and love, than prizesforappearancedespitethewellfinished packed into a tiny hotel room like a demented sonicsar- enclosures. Still, the sound was very nice indeed, being dine trying to pick up some of the sound waves being ab- well balanced and possessing excel!ent transient ability. sorbed by the solid wall of bodies around you. Nice legs, shame about the facia? The particular combination from Quantum under B & Ws new offspring is also worth a listen if you get scrutiny here is the 102 pre -amp and 204 power amp. It is a chance. available in many many forms, from ready built and Aside from that people like Trio, Shure, Goldring, tested, down to modules and hardware. In former form it STD, Quad and Crimson made the most pleasing noises will cost you £80.41 (102) and V 53.42 (204). Modules to be detected, others being either too full of people or (minus metalwork) cost £51.75 and £109.42 (204 kit). too empty of ideas to attract the attention. KEF 105s ap- It is worth a few words to point out that Quantum are peared to have been breeding quietly between the stair- in no way, shape, size or form connected with, or any cases - there were hundreds of them everywhere. The prize for making WORST use of your equipment (if you'll pardon the expression) goes to Audiostatic of Holland. They were showing off a quite incredible elec- oRec Disc trostatic 'panel' speaker with built-in valve amplifier - -bpe en Mon Aux and making a right mess of it when we went in.I only Quantum Electrons 102 Quantum Electronecs 204 rnw ETI JULY 1980 43 part of; Crimson Electrik, the company that is now their awkward room as there is no tonal correction facility at biggest rival. Tim Nind, Quantum's designer and brain all. Still,if you need it build an equaliser as treble and trust, left Crimson to form Quantum and is rightly niggl- bass probably won't help anyway. ed by being repeatedly referred to as part of the com- Tape sensitivity is variable by on -board switching and pany he is now in battle against. The products are both as all hardware is of board mounting varietythere is lit- black(!) and that is as far as any similarity goes. tle chance for noise/hum et al to creep in past the shield- ed cables that festoon most other equipment. Table One displays the numbers, both claimed and One Oh Two Preamp measured, to which I'll return some paragraphs further The 102 replaces Quantum's earlier 'dual -version' on machine, employing instead a very well thought out 'matching card' system to cater for all sorts of pickup Two Oh Four Power? cartridge from moving coil on down through any sort of Long black boxes would appear to be the only way magnetic variation. British companies can produce amplifiers. Where has all the chromium gone? I think the correct word to describe this shade of approach is functional. 0 .R04 Above: the 204 power amplifier. Finished in an unusual black (!?) The 204 unit consists of two 110W audio modules, PSU with toroidal transformer (which buzzes audibly!) Above: the 102 Quantum pre -amp fullfrontal. It is black, of course. and separate supply for the pre -amp (±15V) One DIN (yeuk!) carries out the pre -amp volts and carries in the A small edge connecting PCB is plugged into the signal for amplification. Neat. Speaker output is via main PCB and carriestheinput matching com- 4mm plugs. Thank God this isn't DIN. ponents. Thus by changing card any pickup loading can The, hardware packageis more orless standard be optimised. Handy for people upgrading, the pre -amp across the range, so that you can house any power you never dates. Even handier for deranged souls like me like, up to around 200W, in the same box. who are always swopping cartridges around. A link has Table One to be made/removed on the board for MC/MM, however, PARAMETER SPECIFIED MEASURED and I fail to see why this could not have gone on the mat- THD < 015% to clipping below noise floor ching card, too. Moving Coil: < 01% to clipping unmeasurable. Input Sensitivity Disc- 3.5mV or 100uV standard. VariableDisc overload 35dB Tape.150mV at 3 5mV and 100uV Overload Disc- 34dB Tape iinfinite Signal to Noise Disc: 70dB ref 3 5mV, or 52dB ref 10001 65d13/50dB Tape 96cIB 85dB Frequency Response. Disc i1dB RIAA 50Hz-20k Hz agreed Tape - *1dE3. 20Hz-20kHz Separation. 46dB at 1kHz, 36dB at 20kHz 45d131.38dB (R on L) Outputs 775mV and 150mV tape agreed & Iropedan, es 600R main. 1k8 on disc, 10k on aux. agreed Table Two PARAMETER SPECIFIED MEASURED Output Posse, (OAS, 8R at 1kHz). 110W 121W Peak Delivery 300 VA 205W Signal to Noise Ratio (unwetghted) >100(113 102dI3 Above: the matching board for the pickup input in close-up. Note THD (any level to the nicely worked up edge connections. This particular board is for a dipping) <0015% below noise Shure V15 IV pickup, I think. Trouble was I tried so many it is now im- agreed possible to remember which one was in when the camera went off! Cain 30dB Power Bandwidth (-3dB). 6Hz-50kHz 5Hz-45kHz Inputs and outputs are via DIN, with phono for disc. Damping Factor (50Hz) 80 agreed As I cannot abide DIN plugs of any sort, this drove me InputImpedance. 50k agreed around the nearest loop. but no criticism intended. Protection Operation ofthe Quantum. As you can see from the photo Load 4R 14R3I graphs, controls have been "minimised" to a volume and balance with input selector arrangement. Adequate in Tables One and Two. These are for the pre -amp and power amp most situations, but Baxandall help you if you live in an respectively, comparing the claims against the measurements. ETI JULY 1980 44 NEWS: Audiophile What A Turn On Funny how all reviewers leave discussing the sound of equipment until the end of an article, as though we test it all out first, THEN sit and listen. No chance. Just like everyone else it's a case of home with the packages, out of the boxes and CLICK In fact unwiring it all to start injecting boring test signals is the worst part of this job. Quite frankly I didn't know what to expect from the Quantum, I knew the sound of its competitor Crimson well and respected it as the best module sound around and comparisons are inevitableI suppose. A direct AB test will have to wait though as our German edition has our Crimson set-up at present and is more than a little reluctant to part company with it. Damn cheek if you ask me, who won the war anyway? So itis to the Lecson AC1/AP3 II combination that the Quantum was to be referenced, using KEF 105 II Above:the 204 power amp revealed. Note the huge toroidal speakers and Coral MC81 and Ortofon/SME 30H car- mains transformer and pre -amp PSU board away to the left. Separate heatsinks are used for each power output device. tridges. (The sound of the latter grows on me the more I Below: a de -cased 102 pre -amp. Most components are PCB mounted to hear it.) cut down interwiring. Instructions on pickup matching are written on Withthe 102 set to moving coil, the first thingI the inside of the lid! (not shown). noticed was the much better noise performance. At first I thought something wasn't connected! The sound is open and beautifully rich in all the little things that make music on a good system worth listening to. The pre -amp is very good indeed, but I felt that against the Lecson the 204 lacked bass punch. The lowest registers were not as well defined, or as 'coherent'. Mid -range and treble were little different. Summary In a word - yes. A good solid product which does its job superbly and gives excellent value formoney, both in terms of its sound quality and its engineering. Home built hi-fi has a new championship contender! Figuring Out The Figures In summary of Tables One and Two we can say that the Quantum 102/204isan amplifier of better than Marantz Esotec average noise performance with excellent distortion Below: the new Marantz Esotec TT 1000 turntable. This employs figures - or lack of them - which has a high enough a glass and aluminium 'sandwich' as a base and a 5mm thick glass turn- table mat. The idea is to cancel any resonances due to the base material overload on the disc input to ensure that no problems and produce a truly non -resonant support. Air suspension is employed will ever be encountered in normal use. to hold this massive machine clear of the ground and the motor is claim- The S/N on moving coil input is very good indeed, ed to have sufficient power to reach full speed in 1/4 turn. Released in practically up to moving magnet input standards and has September - price not yet fixed, but will be VERY high. little hum component to give trouble. No mean feat this. My review Itiodei was set-up, to match the in- evitable Coral MC81 as a 'norm', but I spent many a hap- py hour playing with the matching cards for Ortoton, Goldring and Shure moving magnet designs. The moving coil input bettered Coral's own H300 head amp for noise and distortion - which suggests that the self -standing Quantum moving coil pre -amps would be worth a look or two. The 204s figures are unimpeachable - with the ex- ception of that minimum impedance into protection. I would like to have seen around 2R there - the lower the better I suppose. Still it is honestly specified and lower impedance driving modules are availableifyou're troubled. In use the 204 drove my 105 Its with no sign of distress at all. Check your speaker impedance curves before matching though. Better safe than burning. ETI ETI JULY 1980 45 How do you DIGISOUND put over2,000 LIMITED -vtavitlitig a mice fa aQe wits different tools wieigteteoted at &choir, and toolkitsinto Kluge ETI 80. MODULAR oneenvelope? SYNTHESISER Complete kits or P C.B.'s and individual components supplied. Front panels now available in 1.15mm white PVC clad steel with holes and lettering to the style shown in En. Also blank panels allowing you to put other modules in the same format. Exclusive suppliers to the U.K. hobby market for customised I.C.s from Solid State Music and Curtis Electromusic Specialties for use in music and other audio applications. I.C.'s include voltage controlled oscillators, filters, amplifiers and envelope generators. Also stocks of the elusive Q81 temperature compensating resistor (1k, 1 %). Send S.A.E., or1 2p in stamps, for current price list of components and range of synthesiser modules available. DIGISOUND LIMITED, 13 THE BROOKLANDS, WREA GREEN, PRESTON, LANCS. PR4 2NQ Tel. :0772 683138 (MAIL ORDER ONLY) HARD LABOUR? Not exactly, about 20 hours spent building the amplifier that was the success story of 1979, and has no peers in 1980. The WINTON, 50+50 watts of realHi-Fi using power Mosfet's and a specification and perfor- mance that is totally unprecedented in this price range. You will find it an interesting and absorbing pro- The New Toolrange Catalogue is still the ject, serve time and get your just deserts. only comprehensive single source of Act Now, send us a 10p stamp and we will send you a spec' sheet that will make you sit quietlyfor a electronic tools and production aids. while reflecting just how ordinary some amps Products from over 100 top manufacturers really are, or get involved at once, send us your cheque for the best value in Hi-Fi kits around are available from stock. Power MOSFET's rule, ok? For your free copy of the new catalogue COMPLETE KIT, of all parts necessary to build the P.W. contact Toolrange today. WINTON £133.50 SPECIAL LIMITED OFFER£115 Order with complete confidence (C.W.O. only please) from: T.&T. ELECTRONICS Green Hayes, Surlingham Lane, Rockland St. Mary, Norwich, NR14 7HH. Telephone 05088 632 to Irane PRICE INCLUSIVE OF V.A.T. & CARRIAGE. Upton Road, Reading, Berks. RG3 4JA Callers by appointment only Telephone: Reading (0734) 22245 Telex: 847917 ETI JULY 1980 46 GREENWELD err 11U1 II 1111 443A Mil'brook Road Southampton SO1 OHX Build the World Famous All prices include VAT @ 15% - just add 40p post COMPONENT PANELS CHROMA-CHIME Z525 Contains 11 800mA 60V 2N5061 SCRs. OUT NOW 11 6V8 zeners, 11 1N4004 diodes plus Rs, Cs, THE etc. Only El. 74 Series ICs - Gates and complex logic, 20 asstd NEW ICs on panels El; 100 ICs E4. Z527 2 X6V reed relays. 6 X2S030 or 25230. 1980 6 x 400V reds. plus Rs Only 50p GREENWELD TM4030 RAM 4096 bit dynamic RAM with 300ns access time; CATALOGUE 47Ons cycle time; single low capacitance high level clock Up; fully TTL compatible; low power FEATURES INCLUDE: dissipation. Supplied with data £2.75. 60p Discount Vouchers Quantity prices for bulk buyers VEROCASE SALE!!! Bargain List Supplement Only one size left now - these have sold Reply Paid Envelope very fast - if you want a 1/2 price case like Priority Order Form 75-3008, only in GREEN, order one now!! VAT inclusive prices 21051 180x120x 85mm42.30. PRICE40p +35p POST Give your fnendsa warm welcome BUY A COMPLETE RANGE OF This kit has been carefully prepared so that practically anyone BULK SUPPLIES COMPONENTS AND THESE AN new full spec. devices. Prices are for a capable of neat soldering will have complete success in building it. minimum of 100 of any one device and The kit manual contains step by step constructional details PACKS WILL HELP YOU exclude VAT, which must be added at 15 Minimum order value from this section is together with a fault finding guide, circuit description, installation ALL PACKS CONTAIN FULL SPEC. BRAND NEW El 0 +VAT +post. VAT receipt on request. MARKED DEVICES - SENT BY RETURN OF details and operational instructions all well illustrated with POST, VAT INCLUSIVE PRICES. AC187K 20 8E757 27 40161/2 .45 BER40 17 numerous figures and diagrams. K001 50V ceramic plate capacitor. 5%. 10 of BC107 07 BFW43 .32 Handsome purpose built cabinet each value 22pF to 1.000pF, total 210. E3.69. BC108 .08 BFY17 .19 1(002 Extended range 22pF to 0.1 ,F, 330 values BC109 .07 W050 .13 Easy to build and install E5.53. BC114 .06 BFY51 .13 Uses Texas Instruments TMS1000 microcomputer K003 Polyester capacitors. 10 each of these BC117 .07 8E752 .13 Absolutely all partssupplfed including I.C. socket values. 0.01, 0.015, 0.022. 0.033. 0.047, BC118 05 BFY56A .16 0.068, 0.1, 0.15. 0.22. 0.33, 0.47a. 110 BC119 14 BEY 564 .16 Ready drilled and legended PCB included altogether for E5.07. BC125 .06 BFY64 .15 Comprehensive kit manual with full circuit details K004 Mylar capacitors, min 100V type 10 each BC139 14 89101 .28 all values from 1,000pF to 10,000pF. Total 130 BC147 05 BRX48 095 No previous microcomputer experience necessary for E4.05. 8C148 .05 BRY46 .17 All programming permanently retained is on chip ROM 8007. Electrolytic capacitors 25V working smell BC1488 05 BSX20 .075 Can be built in about 3 hoursl physical size. 10 each of these popular values 1. BC149 05 BSY38 .12 2.2. 4.7. 10, 22.47, 1000F. Total 70 for E3.69. 8C159 .05 BSY56 10 Runs off 2 PP3 type batteries. KOOS Extended range, as above. also including BC168C .055 85782 .19 Fully Guaranteed 220, 470 and 1000,E. Total of 100 for E6.05. BC169C .055 BSY85 .23 K021 Miniature carbon film 5% resistors CR25 or BC172C .05 BSY954 .065 * Save freuta4 co go zetadttrzz:ce4 6wicei., 9.04744 nmiler. 10 of each value from 109 to 1M, E12 BC177 BT121 .90 senes. Total 610 resistors E6.16. BC1828 .045 BU205 .60 1(022 Extended range. Total 850 resistors from BC1838 .045 8U206 .60 I R to 10M E6.50. BC184 LfE051.045 BU407 .60 K 041 Zeiler diodes 400mW 5% BIM, etc. 10 8C212 .045 CV7001 .23 of each value from 2.7V to 36V. E24 senes. Total BC2128 .045 CV7493 .19 280 for £16.37. BC213L .045 CV7588 .18 TMS BC214LIT051.045 ME0475 .055 BC237 .05 MJE340 .22 REGULATED PSU PANEL BC2378 .05 MPS2369 .08 BC237C .055 MPS3638A .06 .05 MPS6515 .06 Exclusive Greenweld design - better spec. than BC2385 1000N MPS/166 .24 anything on the market being offered at the price. BC23911 .055 BC252 .07 0C44 .19 Panel 110x82 x 33mrn high contains all com- 0C45 .17 -MP0027A Micro -computer chip ponents including bridge rectifier and smoothing 13C2564 .05 8C308 .05 0C139 .26 capacitor. Reedy built and tested - just add a 30V .63 2A transformer and two pots for a fully variable BC308B .055 OCP71 available separately if required. Full BC320 PBC108 .065 voltage and current supply. .07 BC328 .07 TIP32 .22 BC337 .07 TIP41A .28 24 tune spec device fully guaranteed. BC348 .07 TIP424 29 SPEC. Output voltage 0-28V Output current 20m4-24 BC351 .14 TIP2955 .46 BC413 This unique chip can be used not only for Source Impedance OR I 05 TIP3055 .45 Open circuit ripple 10mV BC485B .06 TIS91 .12 BC4864 .06 ZTX107 .06 electronic door chimes but for other projects BC5468 .06 ITX212 .06 Send SAE for full details of the many ways this requiring musical output:New low price only useful module can be used, together with price list BC547C 055 215214 .06 of parts for various options. Only E6.75 BC 5488 .05 ITX303 .07 BC5564 06 ZTX311 .07 Car Horns BC55613 .06 ITX31 3 .06 BC5574 .06 ZTX341 .07 Musical Boxes BC737 07 ZTX450 06 Amusement Machines TRANSISTOR PACK K516 BCX32 .05 ZTX501 .96 Free applications manual BCX33 .05 ZTX503 .07 Alarms Take advantage of this unbelievable of fen BCY32 .12 ZTX550 .06 and data supplied with device' Small signal NPN NP transistors inplastic BCY71 .11 251021 .94 Public Address etc (Or 30p separately I package at an incredibly low. low price! Almost ell 8CY72 .10 291132 .16 are marked with type number - almost all are full BD112 .84 2N1377 .62 specdevices. Some have bent leads. Over 30 B0131 .18 251711 18 different types have been found by us including BD132 .18 2N1893 .16 BC184 / 212 /238 /307 /328, 8E196 /7. BD133 .18 2N2369 .12 BD137 .20 2N2646 34 ALL CHROMATRONICS PRODUCTS SUPPLIED WITH MONEY BACK GUARANTEE ZTX107/8 /9/34Z/450/550. etc. Only avail- PLEASE ALLOW 7-21 DAYS FOR DELIVERY able as a mixed pack et E3 per 100; E7 per 250 BD138 .20 252894 .12 E25 per 1000. 801 81 .40 25 2926Y .045 80184 .45 2N 2926R .045 BD246 .30 2N3053 .13 ETI 7 80 BD2784 .32 25 3064 36 Please send me: BUZZERS, MOTORS 80433 .32 2N3055 .30 B0525 .24 2N3442 78 TO: CHROMATRONICS, RIVER WAY, HARLOW, ESSEX. & RELAYS 80526 .24 2N3583 .42 Z401 Powerful 6V DC buzzer. all metal construc- BD5434 .30 2N3618 .80 NAME tion. 50mm diet X 20mm 70p. BD695A .45 253702-10 .045 Z402 Miniature type buzzer. 6, 9 or 12V. only BD6964 .45 254124 .08 ADDRESS 22 x15 x16rnrn. Very neat 53p 8E173 .13 25 4400 08 Z450 Miniature 6V DC motor, high quality type BF 181 .15 254401 .06 32mm dia X 25mm high, with 12mm spindle. 8E195 .055 254403 .06 Only E1. 8E196 .055 254410 .06 A372 Audible Warning device - solid state circuit BF197 .055 255193 20 drives high efficiency transducer to give high BEI 98 .055 2N5195 .22 cutout. Voltage reqd 4-18V Can also be driven BF24I .055 25 5401 .17 I enclose cheque/PO value £ direct from TTL or CMOS. Module size 6E255 .075 2N5447 .06 45x 21 x 12mm. Comprehensive data supplied 8E257 .19 2N5831 08 E1.50 BF 258 .20 256121 16 or debit my ACCESS/BARCLAYCARD account no W892 Heavy Duty 12V relay. ideal for car use - BF324 .13 2SC536 05 single 15A make contact. Coil 25R in sealed metal 8E337 .19 2SCI617 .62 can with mounting bracket 115p. 8E355 .18 25C206B 43 W890 DIL Reed relay SPCO 2.4.10V 200R coil 0F394 .055 2SC2073 .45 Only E2.20. BF414 .065 Signature 8E450 .095 Send SAE for latest BF451 .09 bulk buyers list. See last month's ad for other items. CHROMATROMICS ETI JULY 1980 47 e"-", EXTRA LE TO 0 electronics 4K MEMORY 56 FORTIS GREEN ROAD MUSWELL HILL LONDON N10 3HN 8x 21 14 TELEPHONE 01-883 3705 01-883 2289 ONLY £32 +VAT your sound& connection inthe world of component, INCLUDED FREE NOW AVAILABLE Sample tape with extended machine code moditor and Low cost computer in kit form disassembler Price includes RF modulator and UK101 power supply NO EXTRAS NEEDED ABSOLUTELY NO EXTRAS SIMPLY HIT NEEDED 'RETURN' AND GO Also available ready assembled, tested and ready to go As seen in NEW only £249 +VAT P.E. MONITOR August to November '79 FOR UK101 £22.00 Build, understand, and program your own Demonstration At Our Shop Kit price + VAT only £199 +VAT computer for only a (enter through stationers) small outlay 6502 Assembler/Editor for UK101 £14.90 + VAT STOP PRESS The latest edition of our 'STOP PRESS' is now available, and contains an up-to-date price list showing all the items that we stock. Just sendan S.A.E. or phone for your FREE copy. 74LSI 25 0.3 74LS279 0.57 CA3046 0.65 LS series Dynamic RAMS Interface CASE AVAILABLE 74LS00 0.1874LSI 26 0.3674LS283 1.09 8205 3.00CA3053 0.72 0.60 74LS289 4.50 2.00 £24.50 74 LS01 0.1874LS132 4027 3.01 8212 2.00CA3075 74L5133 0.3974LS290 0.91 CA30785 1.90 74LS02 0.18 4050 (20Onsl 2.50 8216 2.08 74LS03 0.1974LSI36 0.3674LS293 0.91 4050 (35Ons) 2.77CA3080 0.67 LM30(35N 1.50SN 76660N 0.75 2.35 8224 0.7574LSO4 0.2074LS138 0.6574LS295 1.30 4060 (300ns) 2.39 8228 4.13CA3080E 0.67 LM 3900N 0.50SN 76666N 74LSI39 0.65 1.16 TAA263 2.2074LS05 0.22 74LS298 4116 5.75 8251 5.00CA3081 1.30 LM3905N 1.00 74LSI45 0.97 1.39 TAA3204 0.5074LS08 0.20 74LS348 8253 6.93CA3082 1.30 LM3909N 0.68 74LS151 0.8174LS352 1.04 0.45LM3911N 1.10TBA1205 0.7074LS09 0.22 Static RAMS 8255 4.95CA3086 0.2074LS153 0.5274LS353 0.92 1.16 CA3089 1.75 M252 81 AA 7.50TBA23I 1.0074 LSIO 2102A 741511 0.2074LS 154 1.3074LS362 4.21 2102A-2 1.16 CA3090Q 3.95 M253 81 AA 7.95TBA 520Q 1.00 Baud Rate 1.00TBA530Q 1.5074LSI2 0.2074LSI 55 0.72 74LS365 0.47 21114-1 1.70 Generators CA3097E 1.85 MC1310P 0.72,74LS366 0.47 1.70 MC1312P 1.85TBA 540Q 1.5074LSI 3 0.3774LS156 2112A-2 2.35 MC14411 5.87CA3123E 74LS157 0.5774LS367 0.47 0.98 0.85 MCI 314P 3.35TBA550Q 1.5074LSI 4 0.65 21L02 MM5307 9.38CA3130E 0.2074LS158 0.5774LS368 0.47 2114 4.50 CA3I 40E 0.36 MC1315P 5.50T13,45600 3.7574LS15 0.95TBA65I 1.8074LS20 0.2074LSI60 1.0974LS373 0.78 4035 (1000ns)1.07 DARTS CA3I 60E 1.00 MCI 327P 74LS386 0.36 3.69 MC1330P 1.00TBA750Q 2.6474LS2I 0.2074LS161 0.69 4045 (250ns) 6.15 AY -5-101 3 3.90CA3600E 74LS162 1.1674LS393 0.84 5257 (TMS4044) ICL70384 3.57 MC1350P 1.20TBA 800 0.83 74LS22 0.20 MM5303 5.04 1.2474LS26 0.20741_5163 0.6974LS668 1.17 6.93 TMS6011NC 3.55ICL8038BC 8.82 MC1351P 1.20TBA81 OS 1.35TBA810AS 1.0074LS27 0.2074LS164 1.0674LS670 1.71 6810 3.48 ICL8038CC 3.40 MC1352P 0.72 ITT7120 1.90 MC1 375P 1.73TBA820 0.7674LS28 0.2074LS165 74LS30 74LS166 1.65 ROMS 2708 LF35 1 N 0.40 MC14451_ 2.95TBA920Q 1.75 0.20 1.5074 LS32 0.2674L5168 1.71 2513 (U. C.) 6.25 only 4 LF356N 0.80 MC1456CG 1.75TBA9900. 8 x 41161 MC1458CP1 0.45TC4270Q 1.0074LS33 0.2674LS169 1.71 only 2513 (LC) 6.25 LM3014H 0.36 74LSI70 1.72 £5.75. LM301 AN 0.25 MCI 495L 5.98TC4730 3.9774LS37 0.23 0.2374LS173 0.81 CPU +VAT LM 307H 0.66 MCI 496P 0.75TC4740 3.9774 LS38 £40.00 - TCA940 1.6074LS40 0.1874LS174 0.97 +VAT 6800 5.90 LM307N 0.43 MC3302P 0.65 0.97 4.95 LM308N 0.95 MC3340P 1.59TDA1054 1.2074LS42 0.6574LS175 8080 Integrated Circuits 0.8174LS181 2.77 9900 26.05 703 (8 pin) 0.95LM308N 0.55 MEM 780 2.48TDA1327 0.9574LS47 0.8174LSI 88 0.44 Z80 9.00 709 (8 pin) 0.35 LM308T 0.95 NE531N 1.00TDA I 352 1.3574LS48 NE540L 2.97TDA2020 3.2074LS49 0.8174LS189 2.08 6502 9.50 709 (14 pm) 0.38LM319H 2.25 0.86 3.87 NE555N 0.22TL072CP 0.9574LS51 0.1874LS190 709 (T099) 0.45LM322N 74LS191 0.86 21102 0.36LM324N 0.50 NE556N 0.60IL 074CN 1.5074LS 54 0.18 E -PROMS 710 (8 pm) 0.1874LS192 1.04 17024Q 5.16 710 (14 pin) 0.38LM339N 0.50 NE560N 3.25TL081CP 0.4574LS 55 8 for 74LS73 0.3374LS193 1.04 2708 5.75 710 (T099) 0.45LM348N 0.90 NE 561N 3.95TL082CP 0.95 3.95TL083CP 1.2474LS74 0.3074LS194 0.86 2716 17.50 711 (14 pm) 0.40LM370N 2.90 NE 562N 0.97 £7.00 2.05 NE565N 1.10TL084CN 1.35 74LS75 0.4074LS195 711 (T099) 0.87LM37IH 74LS76 0.2774LS196 0.97 T.V. Controller 739 (14 pin) 1.80LM373N 2.90 NE566N 1.20U44170 1.98 NE567N 1.35U44180 1.9874LS78 0.2774LSI97 0.97 SFF96364 10.50 741 (8 pin) 0.18LM374N 2.90 0.7874LS221 0.92 16 for 0.35LM377N 1.75 SAA1024 3.40ZN 404 0.8074LS83 741 (14 pm) 74LS85 0.8174LS240 2.08 741 (1099) 0.42LM378N 2.05 SAA1025 4.85ZN414 0.80 ZN417E 1.9074LS86 0.2774LS24 1 2.08 £13.00 Buffers 747 (14 pin) 0.70LM379S 3.75 SL4144 1.90 2.08 SL440 2.90ZN 4237 1.0574LS90 0.5774LS242 74365 0.52 748 (8 pm) 0.33LM380N8 0.85 74LS243 2.08 0.52 SD6000V 2.98ZN 424E 1.1574LS91 0.97 74366 748 (14 pm) 0.45LM380N 0.75 74LS245 2.50 0.52 1.45 SN 75491N 0.75ZN 424P 0.8074LS92 0.69 74367 748 (7099) 0.48LM381N 0.6074LS247 1.09 32 for 74368 0.52 753 (8 pm) 1.50LM381 AN 2.50 SN 75492N 0.85ZN 425E 3.7574LS93 74LS95 0.8174 LS248 1.09 81LS95 1.25 AY -10212 5.80LM382N 1.20 SN76001N 0.95ZN 458A 1.35 £25.00 74LS96 1.1674LS249 1.09 81LS96 1.25AY -1-5050 1.90LM386N 0.78 SN76003N 1.98ZN459CP 2.73 74LS107 0.3274LS251 0.96 81LS97 1.25 AY -1-5051 1.45LM387N 0.95 SN76008K 1.60ZN1034E 1.90 74LS109 0.32741.5253 0.92 1.25 AY -16721 ; 6 1.95LM389N 0.95 SN76013N 1.40ZN1040E 6.85 81LS98 74LS112 0.3274LS257 0.92 8726 1.90 AY -3-8500 5.00LM725CN 2.25 SN 76013ND 1.40ZN1066E 5.85 64 for 1.50ZNAI 1 6E 4.9574LS113 0.3274LS258 0.92 8728 1.90 AY -5-1224 2.40LM 1303N 1.00 SN 76018K 74LS259 1.39 1.57 1.30ZNA134J 26.9574LS114 0.32 8795 AY -5-3507 4.15 LM 1808N 1.95 SN76023ND 74LS261 4.50 £45.00 1.57 5.40 SN76033N 2.00 74LS122 0.69 All excluding VAT 8796 AY -5-4007 6.30 LM1812N 0.7274LS266 0.37 1.57 1.10 LM 1820N 1.00 SN76532N 1.55 74LS123 8T97 CA3036 74LS124 1.3974LS273 1.70 8798 1.57CA3045F 1.40LM18^,IN 1.98 SN 76544N 1.25 All prices are EXCLUSIVE of VAT. Pos age and packing 30p (computers charged at cost).CALLERS WELCOME. Hours 9.00 am -6.00 pm (enter through stationers). TRADE and EXPORT inquiries welcome. Phone your orders through our ORDER -RING linequoting your ACCESS or BARCLAYCARD number (Min. tel order E5). ETI JULY 1980 48 FEATURE CAPACITORS AND TIME CONSTANTS A.S.Lipson takes the bull by the time constants and explains how to use capacitors in timing circuits. hose little brown discs or large blue cylinders that do funny things to your multimeter if you try to Vo measure their resistances are frequently used as AC coupling devices, but they are also of great use in timing circuits. A resistor and capacitor together can produce a changing voltage whose magnitude at any moment can easily be calculated. fp: RxC vo Fig.2 The output voltages associated with the RC networks of Fig.1. matter how long the voltage has been changing in the cir- cuit,italways takes rS for the voltage across the T L capacitor (in the first circuit) to increase by two thirds of Fig.1 Series and parallel RC networks. the remaining voltage. eg If Vo is 9V, and the output voltage V at a timetis 4V, then after rS, at time First The Circuits t + 7, V will have risen by two thirds of (9 - 4) volts, or 3 The first circuit in Fig. 1 consists of a resistor, R in 1/3 volts. This can be used to plot a graph of V against series with a capacitor, C. A voltage, Vo,is applied time. At r seconds, V will be two thirds of Vo. At 2TS, V across the combination and the output voltage (that will have risen by two thirds of the remaining voltage, ie across the capacitor) is monitored. The output voltage by two thirds of 1/3V0, and will thus have risen to eight (V) slowly rises from zero, coming closer and closer to ninths (approximately) of Vo. Similarly, voltages at 3rS, the value of Vo, although it never actually quite reaches 4rS and so on may be calculated and plotted on a graph it. A graph showing output voltage plotted against time (Table 1and Fig.3). A line may then be drawn in is shown in Fig. 2a. It is found by experiment that the rate freehand, joining the points, and approximate values for of increase of voltage becomes smaller if either R or C V at different times calculated. are increased, and greater if either is decreased. That is, This is all very well for rough values, but it is of con- the voltage rises more slowly for large values of R and C siderably less use if we want to find exact figures - than it does for small values of C. In fact, if we take the especially at times much less than the time constant. Fig. product RxC, (R in ohms, C in Farads) we find that this 4 shows a freehand curve drawn onto the first three gives the time (in seconds) required for the output calculated points on a graph. We know nothing from our voltage V to reach about two thirds the value of Vo. method about the voltage before it reaches 2/3 of its final value, except thatitstarts at zero. The correct consistsof a The secondofthe two circuits graph could be A or B or anything in between - we have capacitorandresistorconnectedinparallel.The capacitor is charged by an external source to a voltage no way of knowing, Vo, and then disconnected. The output voltage, V is vo monitored once again. Here, we find that V slowly , 00 decreases from Vo to zero, getting smaller and smaller, but, again never quite making it (Fig. 2b). Again, itis found that the voltage changes more slowly if either the resistance or the capacitance (or both) are increased and changes faster if they are decreased. Time Constant The product RxC is called the 'time constant' r (the 2 3: 2 greek letter Tau) of the circuit and it can be used to find Fig.3Plotting graphs of output voltage againstmultiples of time rough values for V at different times. It turns out that, no constant. ETI JULY 1980 49 FEATURE: Capacitors And Time Constants Fig.4 A freehand curve drawn onto the first Capacitors. three points calculated. We are so used to thinking in terms of currents and voltages that itis very easy to forget the existence of a more basic quantity - charge. Charge is what passes when a current exists. Current, then, is actually rate of passage of charge. Now capacitance is defined as the ratio of the charge stored in a component to the voltage developed across it. That is,if C is the capacitance in Farads, Q is the charge in coulombs and V is the voltage, Curve Drawing (No, Not ...) or C = QN Q = VC It is an interesting and useful property of the way in We can differentiate each side of the equation:- which the voltage changes in these circuits that, at any instant, if the voltage continued to increase (or decrease) d v dC dV at the same rate, it would reach its final value in exactly dt dtd(VC) rS. The reason why it doesn't actually do this is simply Now C is a constant, so dC/dt is zero:- that the rate of increase is not constant. As the voltage dQ dV itsrate of becomes larger (Fig.1 a) or smaller (Fig.1 b) dt= Cdt change decreases. However, as has been stated,if the Finally, we can see that, since current is rate of flow of rate of increase of the voltage, dV/dt was constant from charge, dQ/dt is the current flowing into the capacitor, so any time t, then V would reach Vo (or zero, as the case may be) at time t + r(Fig.5). I = CdV v Now let's take another look at the circuit in Fig.1a. If 1r vo Fig.5 V tends towards Vo. we assume that no current is being drawn from the out- put, then the current into the capacitor must equal the current through the resistor. The voltage across the resistor, though, VR, is obviously equal to Vo-V, and by Ohm's law; (Vo( = I Therefore, (Vo-V)/R 'cltAV Vo-V = RCdtdV -- This is the differential equation that must be solved to find V. The mathematicians out there might like to show We can make use of this property of the curve. Mark that the equation on the graph (Fig.6) a line representing the final voltage, (1-e-t/RC) Vo, of the system. Now mark along this line a distance r V = Vo from the beginning (point A) and draw in a straight line where e, as any scientific pocket calculator will tell you, from this point to the origin, 0. This, then, will give a fair is 2.7182818 and tis the elapsed time. This is the equa- approximation to the voltage as it changes in the first few tion we can use for precise values. We'll do an example; moments. Now choose a point on this line, near the bot- a 9V power source is connected across a series combina- tom (P1). Mark a distance r along from P1 and find the tion of a 47k resistor and a 10uF capacitor. What is the point on the line representing Vo directly above. Call this voltage across the capacitor after 0.6 S? Fitting the point B. Draw a line from P1 to B. Now choose a point P2, values into the equation:- near P1 on this line, and repeat the same process. Even- V = Vo (1-e-t/RC) tually, the lines shape themselves round a curve, which = 9 x(1 -ex p (0.6/(4.7x104 x 101) turns out to be a fair approximation to the graph of = 6V49 voltage plotted against time. (If you don't believe me, try it ...) This method is fine, but it has three great disadvan- A similar sort of argument works for the circuit in Fig.1 b. tages; it takes a long time to draw the curve this way, it The output voltage V is given, by Ohm's law, by isn't very accurate beyond about 2r and (as you will have V = IR realised if you had to read the last few paragraphs more However, Iin this case is the current flowing out of the than four times) it's complicated.If we want to find capacitor, and so it is given by the relation values of V beyond r seconds, we can use the first method of drawing the graph and if we want values of V I = -CdV dt for times less than r seconds, this second method can be Hence we have used, but it is simpler, if we only want to know one value, V = -RCddV t V 0 Fig.6 This method of drawing graphs is And we find that this differential equation has the solution reasonably accurate V = Voe-t/RC up to twice the time constant. where Vo is the voltage to which the capacitor was charged. Let us suppose we have a 200 uF capacitor in parallel LINES ARE DRAWN FROM 0 TO A, P1 with a 330k resistor. The capacitor is charged up to 12 V TO B, P2 TO C AND SO ON THE CLOSER P1,P2, P3 etc ARE PLACED, THE MORE and the supply removed. What is the voltage across it ACCURATE THE GRAPH BECOMES after 2 S? Well, plugging these values into our equation, Vo is 12 V, t is 2 S, R is 3.3 x 105 ohms, and C is 2 x 104 ETI 50 ETI JULY 1980 o (ID MUSIC MEASURING Digital thermometer (80045) LCD display (supplied without relay) £28.95 LED display (supplied without relay) £23.20 Chorosynth (80060). A cheap mini -synthesizer . Relay (two pole changeover) £2.45 £57.90 AC millivoltmeter (79035). FET input meter circuit Elektor vocoder (80060). The first vocoder designed and audio generator £6.30 to be built from a kit with excellent features. It has Universal digital meter (79005). Digital replacement 10 channels £162.50 for pointer instruments £14.65 Front panels for vocoder per channel £1.25 Precision timebase (9448). Generates a precision 1 Analog reverberation unit (9973). Kit with 1 SAD Hertz pulse £13.10 1024 £27.70 Power supply for timebase £5.40 f=5 -1-77.7r-1 Piano. Excellent kit of an electronic piano with three Universal timebase (781009. Crystal controlled voices. timebase £18.70 II Master tone oscillator /generator . . . £37.00 1/ 4 GHz counter (9887 1 + 2 + 3 + 4). Excellent kit Octave PCB (9914) £18.75 count up to 250 MHz £98.15 Filter PCB (9981) £16.50 %mounter (9927). 1K Nz 4 digit display £27.70 HOME Power supply (9979) £19.05 Steam train and whistle (80019). Simulates the Audio analyser (9932). An analyser which can point Digital reverberation unit main board . . . . £67.20 sound on steam and whistle £6.50 the deficiencies in a particular audio chain or Extension boards £46.30 environment £14.80 Clap switch (79026). You clap your hands and the Spot sinewave generator (9948). Programmable light comes on £8.60 sinewaves with less than 0.0025% THD£12.95 Elekdoorbell (79095). Program your own signature Simple function generator (9453). Sine, square and £22.00 sawtooth outputs £27.70 Touch dimmer (78065). Room lighting controlled by Sinewave generator (79019). Always sinewaves single touch NEW - NEW when you need them £8.90 TV sound modulator (9925) £3.75 £5.70 TV scope basic version (9968 1 / 5). Produces display Simple sound effects (79077) up to 1 KHz on TV £34.50 Electronic nuisance (80016) £3.85 TV scope advanced version (9969 1/3) Converts Ultrasonic transmitter (audio) (79510) £7.65 basic scope to 100KHz bandwidth . £48.25 Ultrasonic receiver (audio) (79511) £9.95 £32.35 DJ killer (79505) £8.80 Digiscope (9926) £6.50 Digifarad (79088). A digital capacitance meter with a Quiz master (79033) wide range £25.10 Variable fuzz -box (9984) £6.55 Ioniser (9823). Produces a high concentration of Gate dipper (79514). Checks the resonant frequency of a circuit £16.00 negative ions £9.55 Oscillographics (9979). Random displays patterns on your oscilloscope £11.25 Cackling egg timer (9985). Times your egg. then clucks like a hen! £7.20 AUDIO Pools forecaster (79053). Weighs up the odds and Equaliser (9832). Single channe audio equaliser with could win you a fortune £8.15 slidepots £17.70 Loudspeaking telephone amplifier (9987). Amplifies * Battery protection (80109). Forgetting to turn with turnpots £15.60 off the headlights need no longer be a motorist's signal without direct connection £11.50 with preset pots £13.95 Sensitive lightmeter (9886). Light measurement nightmare. This project is designed to monitor the UAA180 LED meter (9817). A two -channel display battery voltage and switch off the lights automati- meter with LEDs £13.00 using silicon photodiode £12.55 cally in all kinds of motor vehicles Nicad charger (79024). Automatically prevents over £5.15 Peak programme meter (9850). For use with * Transistor ignition (80084). A system which UAA180 LED meter to give stereo audio display charge of cells £15.20 - Proximity detector (9974). Detects movement in a combines the most significant advantages of other £13.00 systems including the conventional system! . . room (electric field change) £9.80 Luminant (9949 1 + 2+ 3). A novel LED audio level Central alarm (9950). Master station slave station E20.45 indicator £20.70 £10.85 * A dip -stick probe (80102). There are all kinds of Parametric equaliser (9897) indicators and warning lights in modern cars, but Alarm unit £3.10 filter section (9897-1) £645 an oil temperature indicator is rarely included. The Tone control section (9897-2) £9.20 Touch tuning FM preselect unit (7951 9). With digital easiest way to add this type of indicator to an display Audio analyser (9932). An analyser which can £17.50 existing car is to mount a temperature sensor in the Talk funny (80052). Deliberate electronic distortion of pinpoint the deficiencies in a particular audio chain dip -stick. or environment £14.80 speech and music signals using a single IC, the Project without dip -stick 2206 £3.65 Preconsonant (9954). A high-performance amplifier £9.60 Dip -stick with indicator (short) £11.00 Colour generator (80027). Using coloured light for an .. £5.75 Dip -stick with indicator (long) . . . . E11.45 effective display £19.70 Consonant (9945). A complete audio control pream- * Intelligent wiper delay (80086). This wiper plifier £34.65 Pools predictor (79053) £8.15 delay only needs to be told once what is required of Toppreamp (80031). Mini preamplifier for Topamp or it.It will then carry out your orders until you any other Hi-Fi poweramp £34.30 change them, which you can at any time, Topamp (80023). Hybrid audio power amplifier with instantly £15.85 OM 931 (output 30 watt) £18.50 * Active car aerial (80018-1 + 2)If there is one with OM 961 (output 60 watt) . £33.40 place to use a good aerial it is in a car . £13.85 Stentor (79070). A portable amplifier ideally suited * Stop thief! (80097). There are all sorts of systems for PA £30.00 for protecting cars, but this one is unusual: itis Assistentor (79071). A preamp for use with Stentor deception, rather than protection . . £4.20 £7.00 * Battery voltage indicator (80101). Only a few Elektornado (9874). A 2 f< 50 watt or single components are needed to obtain an optional 100 -watt power amplifier £19.50 indication of the battery condition: a single lamp Electret microphone preamp (9866). Compact design HIGH FREQUENCIES that changes colour as the battery goes into the that fits into the mike £4.85 Aerial amplifier (80022). Improves the sensitivity of danger area £6.85 an existing receiver specify VHF/UHF . £5.45 UHF/VHF modulator (9976). Generates a carrier for TV signals £6.25 Mini shortwave receiver (9920). Interesting introduc- tion to SW radio £6.95 FM IF strip (78087). Using the CA 3189 limiter HOW TO ORDER:te demodulator IC £13.05 Send a cheque or postal order to DORAM ELEC- Stereo decoder (79082). Compatible with the FM IF TRONICS LTD., Fitzroy House, Market Place, strip £15.10 Swaffham, Norfolk, PE37 7QH. All our prices Digital tuning scale (80021). A sophisticated digital include V.A.T. Please add 40p fpr postage and frequency indication £46.30 packing. Ohm aerial (80076 ,1+ 2). A practical shortwave aerial for 1,8-30MHz £10.30 Office hours: Monday -Friday, 9 a.m. to 5 p.m. Telephone Swaffham (0760) 21627. Telex 81 791 2 Buying one of our PROJECT PACKS will save you the frustration of tracking down those evasive com- ponents that hold up the completion of your project. UM IEEE' IIMMI IMP OWN VEIN Our packs include Printed Circuit Board, all the components listed in the article together with sockets and solder. Cases, knobs, etc., can be supplied as extra items if required. Ask for more information . ! / adeboer company am am mooImola ETI JULY 1980 51 OWENS!atAURA SOUNDS Tomorrow's Electronic Organ Kit is Here POSSIBLY A NEW NAME TO YOU, BUT KNOWN IN OVER 25 COUNTRIES FOR THE SUPERIOR INSTRU- MENTS WHICH THIS GERMAN COMPANY PRODUCE. USED BY WEST GERMAN BROADCASTING SERVICE. PLAYED BY KLAUS WUN- DERLICH AND OTHER FAMOUS ORGANISTS. Without doubt the most comprehensive kits and the most up-to-date designs available today. Just consider a few of the features: WERSI is the firstkit producing company applying the latest achievements of the space age technology. This has decisive effects on the technical and musical Precision Master Generator, using quality of WERSI'S electronic organs for the do-it- MOS-LS1. yourselfer. The application of modern integrated circuits, so called ICs, Integrated electronic keying in 1 2L simplifies the organ construction considerably. A single IC technology. may replace up to 10,000 conventional electronic com- Unique - All switch functions are ponents. In addition, ICs save a lot of space and they are extremely programmable. reliable devices. Even the smallest organ has draw- WERSI, however, went a step farther yet. IC's which were not available on the open market, were developed for bars in addition to fixed stops. specific purposes by WERSI engineering. They are being Craftsman -made cabinets available produced by the most highly reputed IC manufacturers in in five veneers. the world. The result: economical electronic organs with the harnesses most up-to-date techniques and unsurpassed musical Ready-made wiring capabilities. eliminate errors. WERSI MAKES DO-IT-YOURSELF CONSTRUCTION EASIER THAN EVER BEFORE AT A FRACTION OF THE PRICE OF THE FULLY ASSEMBLED WERSI RANGE. GET THE FACTS NOW. AURA SOUNDS 14-15 Royal Oak Centre, Brighton Rd., Purley, Surrey. Tel: 01-668-9733 and at 17 Upper Charter Arcade, Barnsley, W. Yorks Tel: Barnsley (0226) 5248. r Please sendme the fullcolour WERSI catalogue, pricelists ands.'-upPoringt literature (weighing 1lb I)I enclose a cheque/p.o. for £1.00. Send now for the Name 104 page Address full -colour catalogue. Send to Aura Sounds IETI 2). 14 /1 5 Royal Oak Centre. Brighton RdPurley, Surrey j ammo. dlimm mommr meow 141,41 ,m e/0 52 ETI JULY 1980 NEWS MICROFILE By popular request Henry Budgettreviews the Sinclair ZX 80 microcomputer kit. Ever since the first announcements and press com- ments on the new Sinclair ZX 80, Microfile's phone has been ringing with readers asking for a review. Well, after a few months of controversy and careful study here is the report you've all been waiting for. Kitted Out If a system such as the ZX 80 is offered in kit form, it is often worth buying it in this form to save the odd few pounds and so we took a kit and built it. There are few components that raise any eyebrows and the whole thing was slotted neatly together in less than two hours. Whilst we were putting it together we also built in the suggested modification to change the video from black on white ("standard") to white on black ("normal") and this has proved very useful. The instructions supplied with the kit are adequate The explanation of many of the functions of the and clear enough to allow any reasonably competent system is very poor indeed and in some cases can lead constructor to achieve success. Thereisacircuit one rather up the garden path. The best function con- diagram of sorts. We found great difficulty in decipher- cealed within the system is the Editor, truly a marvellous ing the various bits and pieces so it would not be of any system. We did wonder why they had made it so good. It great help in debugging a "dead" system. must use up a fair proportion of the available space which, it could be argued, would be better used by pro- The Great Turn On viding more BASIC functions. The first thing to be said about the ZX 80 is that it worked, albeit a little hesitantly. I am rather accustomed The Ins And Outs to full size keys and have yet to come to terms with a Tape interfaces come in many different disguises. touch keyboard. It does work very well, though, and The ZX 80 is no exception and offers an "around 300 shows no signs of wearing away even after weeks of hard Baud" audio cassette interface which works tolerably use. The TV picture produced by the system is less than well. You can experience trouble if you leave both input satisfactory. The much publicised juddering when keys and output jacks connected to the tape recorder but I are pressed is not in the least beneficial and, when you gather a note to this effectis being included in the actually get round to running a program, the blank and manual. The VDU is less praiseworthy, the aforemention- flickering screen is positively unnerving. ed flicker being just one of its little quirks. The problems The BASIC has been another point of considerable really start to occur when you find that the program controversy. Inside the 4K ROM is a compressed Integer crashes every time you fill the screen. The cause is that BASIC, the character set and the (minimal) operating the VDU is acting as a serial output device and needs a system or monitor. This BASIC may give the beginner a buffer. When the buffer is fullit stops everything and feel for high level language programming but anyone tells you - nasty! who has used systems such as PETs or Apples will find it We also encountered another interesting VDU quirk very restrictive. The single keystroke programming facil- for which there appears to be little explanation. On some ity is certainly not my cup -of -tea. I'm too used to typing TVs you encounter you will find that white on black is the whole thing out, but it would be of benefit to the unreadable but black on white is, or vice versa. We also beginner. discovered, again no explanationis offered, that the system would produce a double (ghost) image on some colour sets. The designer assured us that the modulator Manual Intercourse was not, as we had suspected, a cheaper version that The "Course in BASIC Programming" that is supplied could not handle the bandwidth so there must be, with the system is a very poor substitute for books such something funny going on. as "Basic BASIC" and "Illuminating BASIC" but is ade- quate for finding your way round the ZX 80. The format needs to be considerably improved, odd and even Hardware Design chapter numbers are aimed at different people. There A certain number of design features of the ZX 80 are are a number of errors; some are corrected in an adden- worthy of note. It is generally understood that an eight dum, but several trap the unwary. bit micro, with its sixteen bit address bus, can have up to ETI JULY 1980 53 NEWS: Microfile possible to connect exotic systems such as Viewdata and Teletext. In the same way it is impossible to use the ZX 80 for playing interactive video games of the Space In- vaders type. Software At the moment there is not much commercial soft- ware available. The Users Group isprobably the best source after magazines like Computing Today,but there are very strong indications that a professionalsoftware house will be supplying the user with a range of pro- grams. For users who are looking for software nowthe following points should be borne in mind; a) the BASIC is Integer only, b) the cassette format is not "standard", c) you can't use interactive graphics, PEEK and NewBear's New Brain--a professional, hand-held micro POKE, coming soon. d) The BASICisnot compatible with Microsoft 64K of memory hung on it. The ZX 80 offers a maximum types, in either direction. of 16K of RAM and a (possible) 16K of ROM, done by moving PC tracks around. What you may well ask has Conclusion happened to the other 32K? Sorry chaps, but it is used for Sinclair and his Science of Cambridge team have other things like decoding the keyboard, so the thoughts produced what is probably the forerunner of the 1980 of giant, disc based systems fade rather rapidly. Whilst generation of personal computers and in common with on the topic of memory it should be notedthat the 3K most "firsts"it has a number of faults that its com- Sinclair RAM boards are not capable of being "piggy petitors will rapidly seek to iron out of their, yet to be backed", you'll have to wait for the 15K RAM plane. You released, products. The currently poised opposition in- cannot use the cheaper dynamic RAM either because the clude Acorn with their Atom, NewBear with the New RFSH signal produced by the Z80 CPU is utilised by the Brain and (allegedly) Sharp with a similar type of system. video synchronisation circuitry and this means that in- The competition is going to be fierce and as yet Sinclair stead of getting a mean refresh every 2 mS that the is the only runner in the race. dynamic memory needs,it may have to wait 20 mS, As regards the system we feel that it would probably which is cutting things very fine. Under normal operating make a starting point for the complete beginner, but for conditions this might not cause problems, but if the anyone experienced in microcomputing it may nothave temperature of the RAM chips rises then they may well sufficientfacilities compared with other low cost start to lose data. systems like Acorn and Tangerine. The lack of proper The final oddity in the design of the hardware is the machine code access may put the system down in some lack of a crystal controlled clock. It uses a ceramic filter people's opinions but as a first time system for the com- instead. This is not to be recommended as it simply isn't plete beginner, be they in the classroom or at home, it is accurate enough. The ZX 80 runs at 3.25 MHz, which is a currently the cheapest and that may well be the over- multiple of the TV linebase frequency. The filter appears riding factor. to be used to save a couple of divider chips and possibly pass this saving on in a reduced price, but it shouldbe remembered that the earlier Sinclair computer, the now New from NewBear defunct Mk 14, was equipped with a crystal and cost Newbury, the terminal company who opened the about half the price. NewBear computing shops to gain access to the world of microcomputing, have launched a professional hand- held micro for anyone from businessmen to the hobbyist. Expansion Capabilities Called New Brain it contains a 16K Compiling BASIC, 2K Apart from the memory expansion problems men- RAM which is expandable to 4K in static or 16K in tioned earlier, there is another, more subtle, problem dynamic, a fullsize QWERTY keyboard, single line that will occur when the user wishes to attach that most display with direct video output and enough I/O to make popular of peripherals, the printer. This problem arises most systems look a bit undernourished. The wholething because the ZX 80 does not use the normal ASCII is battery powered, with charger capability and uses a character code set but its own. This means that to inter- COPS chip from National Semi tolookafter the face to a printer, a task of more than average complex- keyboard and display (which powers down after 60 ity, the user will have to write a look -up table routine to seconds of inaction). The main computing is provided by convert between the two code sets. a Z80 which only powers up when youactually RUN a However, the first thing that any expansion minded program. The machines we wereshown at the Press user must do is to put buffers onto all the bus lines. launch were unfortunately only half built and they are Space and pricing have omitted these and, although it is not expected to be available until at leastSeptember, so hoped that Sinclair will produce a buffer board, it does we can't get our hands on one yet.When we do we'll tell not appear to rank highly on their list. you what it does but expect the prices tobe from £150 Mention has been made of certain possible add-ons (video only) to £250 (full system). One feature that I will likePrestel anditis worth making the point that, tempt you with is the fact that they havecommitted because the ZX 80 uses a serial output screen format themselves to Prestel - it has a button on the front rather than a memory mapped type, it will be almost im- marked Viewdata. ETI ETI JULY 1980 54 ' CT4000 CLOCK/APPLIANCE TIMER KIT DO MAGAZINE REMOTE CONTROL The CT4000 has been designed to preset the stare (on or off) PROJECTS MAKE of four outputs at four times per day for up to7 days on advance, enabling the unit to control tape recorders. appliances, central heating, lights. etc. The times are sat on a YOU 0.1" high red LED display by means of a keyboard and the eero output states are displayed on four LEDs. Each output can SEE INFRA RED? switch up to 20mA at 9V For mains loads use our Solid State Relay Kit (MK2). The kit includes a PCB. keyswdches, IC. 4 How many times have you considered building a remote control protect but were put off by the dozens of digit LED display, transformer, plus all other components and ICs. special coils. lenses and other hard to get components. nor to mention the need fora well equipped lab a screen printed and drilled box which can also accommodate to set the unit up, T K ELECTRONICS have changed all that. Three ICs can build a sophisticated system up to 4 Solid State Relay Kits. that requires only a capacitor and resistor to set the clock frequency (which can drift up to 20% without ONLY affecting performance). Control radios, Hi-fi (including bass, treble and volume), lighting. toys, garage Site 10x 12 x4 5cms doors. etc. Still not convinced? Then look at the prices, Colour. Black £25.25 M1922 10 -channel Receiver and 3 Analogue Outlat D.V.M. THERMOMETER KIT TOUCH CONTROL LIGHTING KITS ML926 16 -channel Receiver (4 Momentary binary our Based on the ICL 7106 This kit contains a PCB, puts) E1.40 These KITS replace light switches and control up M1928 16 -channel Receiver (4 Latched Binary outputs) resistors, presets, capacitors, diodes. IC and 0.5" to 300 Watts of lighting. No rewiring, fit plaster liquid crystal display. Components are also LD271 IR Emitting Diode 311p E1.40 depth boxes, insulated touchplates. Easy to follow 95p Data sheets (re, device) included to enable the basic DVM kit to be nstr.tions SFH2O5 Photodiode Detector Sp modified to a Digital Thermometer using a single SL480 IC Pulse Amplifier 91.40These ICs can also be used with ultrasonic and radio TD300K TOUCHDIMMER. Single touchplate links. depending on range, cost and speed of operation diode as the sensor. Requires a 3mA 9V supply with alternate action Brief touch switches lamp on SL 490 Keyboard Controlled Encoder/Transmitter (PP3 Itenery) £2 40For more details. why not give us a ring - we will be E20.75 and off, longer touch dims or brightens lamps pleased to advise you Neon lamp helps find the switch in the dark MINI KITS E6.50 Ft you do not require a sophisticated multi -channel remote control, we have developed a simple TDE/K Extension Kit for TID300K for 2 -way single -channel ON /OFF infra red transmitter and receiver Tie transmoner unit comes complete with a switching. etc E1.50 hand held box and requires a PP3 (9V) battery. The receiver includes a mac capable of switching up to These kits form useful subsystems which may be TSD300K TOUCHSWITCH & DIMMER 500W at 240V a c and composes., preamplifier. bistable latch and a mains power supply, making the unit incorporated into larger designs or used alone. Kits Single touchplate. small knob controls brightness completely self-contained The small site of the receiver enables the unit to be "built into" all kinds of include PCB. short instructions and all com- E5.130 equipment from lamps to tape recorders The minimum range is 20 feet. ponents TSA300K TIME DELAY TOUCHSWITCH ONLY E/2.00 (Order as RC500K1 MK1 TEMPERATURE CONTROLLER/ Turns off after preset delay (2 secs. to 31/2 mins THERMOSTAT E4.30 INTEGRATED CIRCUITS Uses LM3911 IC to sense temperature )80"C 10300K Conventional Liqhtdimmer E2.90 TRIACS max) and tree to switch heater. 500W E3.20 1KW £3.50 SN 76477 Complex Sound Generator E2.52 400V Plastic Case (Texas) MK2 SOLID STATE RELAY INTEGRATED CIRCUITS TBABOO 5W Audio Amp 1159 3A 49p 16A 90p TRW OAS 7W Audio Amp Ideal for switching motors. lightsheaters) etc 55p 8A 58p 20A1851, from logic TDA1024 Zero Voltage Switch E1.20 00*o-isolated with zero voltage 555 Timer 21p 12A 85p 25A190p switching. Supplied without mac. Select the 741 Op Amp TDA 2020 20W Audio Amp E2.55 lap ZN1034E Timer 80p required tree from our range. E2.60 AY -5-1224 Clock E1.110 6A with trigger E2.60 All ICs supplied with data sheets. MK3 OAR /DOT DISPLAY AY -5-1230/2 Clock/Timer E4.50 8A isolated tab 65p Data Sheets only 5go each device Displays an analogue voltage on a linear 10 - AY -3-1270 Thermometer E5.20 Dec 18p element LED display as a bar or single dot Ideal for 1CL7106 DVM (LCD drive) £7.00 SPECIAL thermometers. level indicators. etc. May be LM377 Dual 2 W Amp E1.45 stacked to obtain 20 to 100 element displays. LM379S Dual 6W Amp £3.50 orders must be received by 30 6 80 Requires 5-20V supply. E4.75 LM3130 2W Audoo Arno 50p 10 x Boon sockets 66p 10 x 555 o1 80 MK4 PROPORTIONAL TEMPERATURE L M382 Dual/low noise Preamp E1.00 10 x 14pin sockets E1.00 10 x 741 E 1 60 CONTROLLER LM3136 250mW low voltage Amp 75p 10 X 16pin sockets E1.15 25 x 0 2" Red Inds E 1 50 Based on the TDA1024 Zero voltage switch, this LM11330 Fluid Level Detector E1.50 10x 18pon sockets Cl 40 ORP12 50p kit may be wired to form aburst firepower LM2907 f -v Convener (8 pm) E1.40 100 x Soldercon pins 40p 2N3055 40p controller or aproportional temperature" LM291 7 f -v Converter (14 pin) E1.60 controller enabling the temperature of an enclos- L M3909 LED Flasher /Oscillator 55p ALL COMPONENTS ARE BRAND NEW AND TO SPECIFICATION. ADD VAT AT ure to be maintained to within 0.5'C L M39 i1 Thermometer E1.20 CURRENT RATE TO ABOVE PRICES. 40p P&P MAIL ORDER - CALLERS WELCOME 1 5KW E5.25 3KW E5.55 LM3914 Dot / Bar Driver E2.10 BY APPOINTMENT MKS MAINS TIMER MM74C911 4 digit display controller E6.50 Based on the ZN1034E Timer IC this kit will switch MM74C915 7 segment BCD convener 96p a mains load on (or off) for a preset time from 20 MM74C926 4 digit counter with 7 sego / p minutes to 35 hours. Longer or shorter periods E4.50 TK Electronics -fit may be realised by minor component changes S56613 Touchdornmer E2.50 (ETI), 106 STUDLEY GRANGE ROAD Maximum load 11(V)./ E4.50 S9263 Touchswitch 16 -way E4.55 LONDON W7 2LX. TEL. 01-579 9794 110projectsin every book! The'110' books have been acclaimed by enthusiasts, students and engineers. Each contains 110 different circuit applications. Use them as project books or as source books for circuit ideas. 110 CMOS Digital IC Projects for the Home Constructor 110 Operational Amplifier Projects for the Home Constructor R. M. MARSTON 0 408 00216 6 £3.95 R.M. MARSTON 0 408 00153 4 £3.95 110 Electronic Alarm Projects for the Home Constructor 110 Semiconductor Projects for the Home Constructor- R. M. MARSTON 0 408 00269 7 £3.95 Second Edition R. M. MARSTON 0 408 00322 7 £3.95 110 IC Timer Projects for the Home Constructor JULES H. GILDER 0 408 00480 0 £3.95 110 Thyristor Projects using SCRs and Triacs R. M. MARSTON 0 408 00074 5 £3.95 110 Integrated Circuit Projects for the Home Constructor- Second Edition 110 Waveform Generator Projects for the Home Constructor R. M. MARSTON 0 408 00309 X £3.95 R. M. MARSTON 0 408 00353 7 £3.95 Available from your bookshop or in case of difficulty direct from the publishers. -ewnes Technical Books Borough Green, Sevenoaks, Kent TN15 8PH ETI JULY 1980 55 Happy ELECTRO1-YECIE Memories SUPPLIERS OF COMPONENTS THAT COUNT 4116 200ns £3.95 4116 150ns £5.50 2114 200ns £3.95 2114450ns £3.45 2708 450ns £4.95 2716 5 volt £13.50 MEMOREX mini discs soft sectored £19.95 per ten SALE SIEMENS NASCOM VERO 1 SEMI CONDUCTOR MICRO COMPUTERS BOARDS We re moving shortly to new premises and don't CAPACITORS AND CASES & want to carry much FERRITES ANCILLARIES KITS Bargains for all BREADBOARDS All prices include VAT, 30p postage on orders RADIOHM ISKRA POTENTIOMETERS SOLDER TOOLS below £10 RESISTORS Access and Barclaycard OPTO ELECTRONICS SWITCHES CATALOGUE 10 All orders to. Dept. ETI OUR MINI -SELECTION POINTS THE WAY! 19 Bevois Valley Road EXAMPLE ONE - SOLDERING IRONS Arms 50 £12.08 net Antex 25 £4.83 net Southampton, Hants. SO2 OJP Isotip f25.90 net Desolder tool SR3A £7.48 net Telephone (0703) 39267 Antes C £4.83 net 500 gm reel solder E6.61 net EXAMPLE TWO - PRINTED CIRCUIT MATERIALS PCB's 300 x 150 mm Etch Resist Pen £1.14 SRBP S/S £1.38 D:S £1.73 Breadboards F/Glass S/S £1.96 D/S £2.13 Bimboard 12E9.23 Positive resist 75cc Eurobreadboard £6.56 net Ferric Chloride 500 g £3.46 T-DeC £5.18 Standard Parts EXAMPLE THREE - SWITCHES Chrome toggle 13A time switch adaptors Std. SPDT 66p DPDT 89p Smiths TS100 £14.43 net Min. SPOT 116p DPDT 92p Wavechange,Lodin,1P1 2W, 2P6W. 3P4W, 4P3W 411p etude EXAMPLE FOUR - CAPACITORS BY SIEMENS Poly 7.5mm PCM 1, 1.5, 2.2. 3.3, 4.7pF, 10, 15.22. 33, 42pF6,peach..1A.412p, .15p 15p, .22p 18p, lOmm PCM37p. 2,4p, 1/100 1rp, 2.2/25 24p, 2.2/63 15p, 4.7/16 2414.7/40 15p, 10/25 16p1/4010/40 1(42,22/25 lap, 22/40 111p, 22/63 19p, 47/10 1 47/25 19p, 47/40 -2 FG-1 a 18p, 47/63 20p, up to 1000/16V 36p, then 1 000nsv 49p to1/16 65p. Also full supporting ranges of other ceramic, plastic and electrolytic caps. *1 EXAMPLE FIVE - POTENTIOMETERS BY RADIOHM Single gang lin or log 34p Twin types stereo matched) 0 I ® Twin gang lin or log 93p Slider knobs 10p each. Mono slider fin or log 83p Presets lin, horiz, or vert 10p Twin slider lin or lop 136p DIGITAL FUNCTION GENERATOR EXAMPLE SIX - RESISTORS MULTIMETER i. 3. IW 2.3p 1W 6p Wirewound from 21p * DC Volts lmV to 1000V * 30mV to 10y pk'pk AC Volts 1V to 500V AND AS FOR SEMI CONDUCTORS ... DC Current 0 1mA to0.2A * 1Hz to 100kHz 1N914 6p 40673 99p MU481 £1.70 TIP41A 69p Resistance 1(' to zomn 1N4007 9p AC128 36p MJ491 £1.88 T1P41C 74p * DC coupled 1N4148 5p AC176 67p MJ2955 97p T1P42A 69p * 3% digit LCD 1N5402 19p AD136 £4.25 MJE2955 £1.13 T1P42C 74p * Sine, Square & Triangle 2N1599 f1.01 AD149 £1.01 MJE3055 £1.00 T1 P2955 69p * Auto Low Battery indication 2N23690 24p AD161 40p MPSA12 42p T1P3055 69p * Separate TTL output 2N3055 81p 40162 52p MPSA63 44p T1S43 40p * Auto Polarity & Zero 2N3702-11 lip AF127 43p 0A47 14p W02 35p * Designed around Intersil 8038 IC 2N4443 f1.78 AL102 £1.84 0090 14p * 1% accuracy (DC volts) 2N4444 £2.28 B A379 29p 0A91 881: No1210.9 14p * Total cost around E25 (incl. case) 2N4991 98p 813103 43P 00202 16t 627 x 500 16p * Designed around Intersil 7106 IC 2N5457-9 45p BB104 70p 0C29 This list is 40HF40 £2.25 BB105 37p 0C36 V .18 * Total cost around £30 (incl. case) hula fraction 40361 49p C106D1 52p T28000 £1.20 of what we 40362 49p F1110 92p T1P31A 52p carry. Provided in a JAYkit is a Printed Circuit Board, a punched and lettered Front Panel overlay, a 40636 f1.69 E1210 97p T1P32A 62p Circuit Diagram and Instruction Sheet and a comprehensive and up to date Component List INFORMATION - To show everything we supply would take about seven pages of closely showing suppliers and current prices. Difficult to obtain pieces of hardware are supplied with the packed type in this journal - the range is enormous including not only opto devices and very kit. Jaye. Developments 21 GlmIns.de. Bar pss spy advanced sophisticated items, but all the everyday things you need as well down to nuts and washers( ITS ALL IN CATALOGUE 10 - OUR 120 PAGE CATALOGUE FREE FOR THE To. JAVEN Developments ASKING. PRICES AND VA.T. - All prices quoted here include V.A.T. for U.K. orders. Overseas 21 Gladeside, Bar Hill, Name Cambridge CB3 8DY buyers deduct 13% when ordering. Tel: (0954) 80285 POSTAGE - For orders up to f 5.75 value (U.K.) please add 40p for p/p. If over, orders sent Address post free in U.K. Overseas orders sent at cost (Min. 40p). Please send: DISCOUNTS - 5% allowed on non -net items if order value exceeds E 1 1.50.10% if order EDM.2 @ E5.45 value exceeds £29. Quantity discount prices on most components. FG-1a @ £4.95 ELECTROVALUE LTD. Dept. SS St. Judos ROM!, Englefield Green, Eghem, (Incl. VAT and P&P) Surrey TVV20 OHS. Phone Eghem 33603 Telex 264476. Northern Branch (Personal Shoppers only) 680 Burnage Lane, Burnage, Manchester M19 Money to be refunded if the kit 1 NA Phone (061)432 4945. is returned within 10 days. ETI JULY 1980 56 FEATURE TECH TIPS Multi -Flash Trigger R O'Rourke, Eastleigh This circuit providesa cheap and safe .4- .-141-04.- TO FI 2 systemforparallelconnectionfor 100k TO ADDITIONAL SCR1 CAMERAS BTX -18 F41 of ADDITIONAL electronic flashguns and prevents dam- 400 FLASHGUNS age to shutter sync. contacts. o Electronic flashguns used for pho- Cl 20n FLASH GUN tographyusuallyhave a voltageof R1 18k D2 -D5 between +200 V and +400 V present at 1N4007 CAMERA the trigger input connector. SHUTTER CONTACTS The flash unit operates when the 01 1 N5408 triggerisgrounded(bytheshutter sync. contacts) and a current pulse of between 1 and 3 amps, lasting about 10 to 30 microseconds iscarried by the sync. contacts. Directconnectionofelectronic When one or more flashguns are pulseturns on the SCR which then flashgunsinparallelcancause two connected to the unit, the cathodes of carries the trigger current of the flash- major problems: D2-D5 rise to a high positive value, say guns. (a) Different makes or powers of +200 V. When the flashguns fire the trigger flashguns may have different oper- Clis charged via R2, R1 and D1 voltage drops to zero and the SCR turns ating voltages and may therefore in a time constant C1 x (R1 + R2) = off. Cl will recharge as the voltage of be damaged by parallel connection. 0.02 x 118 k = 2.36 mS. the flashguns recover ready for the next (b) Shuttercontactscould be SCR1 is non-conductive at this time flash. damaged or burned by the excess as its cathode is slightly positive and its As can be seen, the maximum cur- current of multiple gun operation. gate is grounded. rentthrough the camera contacts is This circuit overcomes these two prob- When theshuttercontacts of a thusreducedevenwith aflashgun lems as follows: camera connected tothe deviceare voltage of 400 V, to only 22 mA. (a)Diodes D2 to D5 effectively closed the R2 end of Clis grounded When using more than one flashgun isolate the hot side of each flashgun and thereforetheR1 endisdriven ina direct lighting system, allowance from the next and also prevent the negatively to -200 V. This enables a should bemadefortheincreased high voltage appearing on the un- negative current pulse to be delivered guide number:- used flashgun contacts. to the cathode of SCR1 (D1 allows SCR Effective Guide Number = (b) The SCR trigger circuit operates cathode to go negative) of about 11 as follows: mA, for about 360 uS duration, this \/a2+ b2 + --- - Simple Cassette Interface Take the output of the 7402 to the +5V serial input link LK3. R Thomas, Port Talbot Component valuesare R2 notthat 2k2 critical and by inserting another resistor The cassette interfaceon my NASCOM1 and capacitor of the same value in front has never worked correctly and despite of ClandR1 the response willbe many frustrating fault finding sessions improved, although I did not find these Cl 100n 154148 the only solution was to replace it. No necessary. The interface does require a 01 OUTPUT BC 108 originalityis claimed for this circuit. fairly large input signal and the volume OR SIM IL IAR Indeed anyone with a basic knowledge setting is rather precise but once set the INPUT of electronics or radiowillrecognise interfaceshould work perfectly.Al- part of it as an envelope detector or thoughbuiltfor the NASCOM, the demodulator. No alterationofthe interface will work with any low speed cassette output of the NASCOM isre- cassette interface system that switches quiredassumingitdumps properly. an audio frequency on or off. Tech -Tips is an ideas forum and is not aimed at the beginner. We regret we cannot answer querieson these items. ETI is prepared to consider circuits or ideas submitted by readers for this page. All items used will be paid for. Drawingsshould be as clear as possible and the text should preferably be typed. Circuits must not be subject to copyright. Items for consideration should be sent to ETI TECH-TIPS, Electronics Today International, 145 Charing Cross Road, London WC2H OEE. ETI JULY 1980 57 VDU Shift Control R J Cheason, Fareham UNMODIFIED 0/P OF SF F 96364 PIN 10 Most low cost VDU boards using the SFF96364 do not have the facility to adjust the monitor/TV picture left or MODIFIED 0/P right. This circuit was developed for a OF PIN 10 VDU board using the'Triton' design but is suitable for any board using the same controller. 0/P PIN 1 The SFF96364 outputs a pulse on IC1 Pin 10 enabling the picture - point oscillator.Thecounter/dividerthen outputs a pulse to the controller every SET BY RV1 character, stepping the character add- ress. After 64 characters Pin 10 goes 0/P PIN 5 IC2 TO low. PICTURE POINT Themodifiedcircuit uses the OSCILLATOR positive going edge fromPin10 to 0 .5V trigger a monostable whose pulse lengthisset by RV1 and Cl. When the monostable's output goes high it RV1 triggers a flip flop into the high state. 22k After the current line has been output, the input from Pin 10 goes low clear- ICI 10 0 74121 ingtheflipflopandstopping the IC2 I/P 7474 0 FROM SFF96364 picture - point oscillator. PIN 10 TO PICTURE -POINT OSCILLATOR AND LINE Inpracticeslightjitteringwas BLANKING GATE caused by interference on the supply 0 lines, but it was found that a capacitor of about 100 uF across the supply close CIV to IC1 cured this problem. 0 Soft Limiter J.P. Macaulay, Crawley One of the fundamental differences between valve and transistor amplifiers istheirbehaviour when driveninto clipping. The valve amps go into so- calledsoft clipping whilst their tran- sistorisedcounterpartsgeneratelarge quantities of harmonic distortion. The circuit shown simulates the soft clipping of valve amplifiers and is intended to be usedbetweenthepoweramplifier's input and the preamplifier's output. R4 and R5, decoupled by C2 set a halfsupplyreferenceforthenon - inverting input of the op amp. Input signals are fed into the inverting input via the DC blocking capacitor and R1, the latter defining small signal gain and increases due to the shunting effect of The circuitisadjustable in oper- input impedance. R2 and R3. ation between 130 mV and 10 V rms Forsmallsignalstheamplifier's The net effect is that musical peaks input sensitivity by means of PR1. To output is an exact unity gain copy of above a certain threshold are reduced set the circuit up simply set the slider the input. As the signal level increases, inamplitudetopreventthe power so that itis shorted to the output of however, the time will come when the amplifier going into hard clipping. As a theamp.Play some musicathigh voltage across the output and slider of result distortion is noticably decreased, volume through the system and adjust PR1 will be sufficient to bias Q1 or Q2 whilst the subjective loudness appears untiltheharshnessjustdisappears. on. Whenthisoccursthefeedback unaffected. It's easier to do than describe. 58 ETI JULY 1980 FEATURE: TechTips RI s IC -(Ca !CB 555 // 114a IC9a // 1C13,1 <1001. PR? WRONG 11;3, 10 // C3h 1>ISPLAV IIC 14 .1/ C2 ICI 100 4011 IC2f 1.4 Cl- 100 >ft // 21 IC1 A n, NOTES (-1ICIc IC15.9 ARE 4001 ic IC6 I$ 4011 >2 IC7 IS 41 IC7 IS 4017 Li IC8 IS 555 D1 9,1217115 OF Fl ARE 0125" LED 11 D10,11 ARE rLED O after that. In fact, all the parts light up AND gate, connected as a chain linking Electronic Hangman in sequence, until the last part lights, each output of the 4017, so their out- a 'higher' G.N. Durant, Selby when the display blanks again, and the putswillgohigh,when whole'chasing'processstartsagain. LED is lit. lit, another The circuit diagram shows a design for Thisprocessrepeatsitselfuntilthe When the top LED is AND gate(gate3,IC 6) goes low, anElectronicHangman Game. The 'Reset' button is pressed, when the dis- is made up of 0.125" play blanks, ready for a new game to lockinga latching flip-flop formed by scoring display gates 1 and 2 of IC6, a CMOS NAND and 0.2" LEDs, as shown. The controls begin. The circuit consists of eight ICs, gate. This latch allows the output of consist of two one pole make push- an astable multivibrator to go to the buttons. The firstbutton ispressed one of them beinga 4017B CMOS device. This device is a ten stage decade trigger input of the 4017 and to start every time a letter is wrongly guessed. automatic sequencing. The reset At thestart of the game, the other counter. Each output is fed directly to the its own LED and, because some outputs button makes the input of one of the button is pressed, to reset the display, gates go high, unlatching the flip flop blankingit. When aletteris wrongly require more than one LED and there is not enough current from the 4017 to andresetting thedisplay. The small guessed the 'wrong' button is pressed varies the clock rate over a wide display, drive more than one, the affected out- preset once, and the first part of the range, speeding or slowing the sequen- (A), is illuminated. Every time another puts are connected to a CMOS 'AND' 'wrong' gate which isin turn connected to a cing. wrong letterisguessed,the If desired, a 'Display PCB' can be button is pushed, and the next part of LED, sotherequired powerisob- tained from the power supply and not designed to ease the LED wiring. When the display is lit up. When the display is the circuit is known to be functioning lit up, and the victim is 'hung', the the outputs of the 4017. The input of all correctly,linescan bepainted onto display automatically blanks. the 4017 is triggered by a push button where the clever bit connected to the positive supply rail, the display to join up the LEDs, and to Now thisis make them appear as a 'picture'. comes in. To show that the victimhas so when itis pushed (Wrong button) is blanked, then the the IC is triggered and the next part of When all the LEDs are illuminated, lost, the display the circuit will take a great deal of cur- firstpart of the displaylightsitself, the LED displayisilluminated. The then the next part and then the one 'lower' LEDs are keptlitby another rent, so a mains power supply is advised. 59 ETI JULY 1980 24 TUNE DOOR CHIMES AUDIOAND RETAIL ES E17.13 + VAT MAILORDER Waddington 's Videomaster announce a doorbell that doesn't EXPORT go Brrringgg, Ding Dona or Bum Insteadifplays 14 ALLPRICES doff erent classical and popular tunes.Itwill play the tune TESTEQUIPMENT INCLUDE VAT you select for your mood, the season or the visitor you are expecting tocall. Door tunes is not only great tun and a CENTRE wonderful are breaker, butisalso very functionally and Telephone your order with Access and Barclaycards beautifullydesignedto enhance yourhome.Thereis or send cheque with order. something for Christmas, something for your continental at 2(9 visors oryourrelations fromthestates,and even 9 I something for the Queen. Door tunes is easy to install and -a7S. has separate controls for volume, tone and tempo PROGILMAMMILEalso+ VAT. LONDON'S TEST GEAR CENTRE COLOUR CARTRIDGE T.V. GAME. The TV game can be compared to an audin cassette deck OPEN 6 DAYS A WEEK 9 am -6 pm and a programmed to play a multitude of different games HAMEG TRIO LEADER SINCLAIR LASCAR LEVELL CSC in COLOUR, using various plug in cartridges. At long last a Test Equipment now in stock -send large s.a.e. TV game is available which wil keep pace with improving SCOPES-ILIK P /P E2.50 ea.l FREQUENCY technology by allowing you to extend your library of games HM 307-3 10MHz single beam with Component Tester 170.00 with the purchase of additional cartridges as new games HM 3122 20MHz dual trace 287.50 COUNTERS are developed. Each cartridge contains up to ten different HM 412-4 20MHz sweep delay dual trace 402.50 OPTO 7010 9 digit, 600MHz action games and the first cartridge containing ten sports SINCLAIR 10MHz Minwope P /5 4.00, Nicads 7.95, Case 8.80Portable.0.1 HZ Resolution with NiCADS . games a included tree vat the console. Other cartridges 152.50 139.95 EXTRA CARTRIDGES PROBES .1 . x 10 12.95, .1 0 10.50ii1 8.50 .100 16.95 MAX 50 50MHz 6 digit are currently available to enable you to play such games as pocket counter 111.00 Grand Pnx Motor Racing, Super Wipeout and Stunt Rider. ROAD RACE - 131.87 + VAT. MAX 100 100MHz 8 digit Further canridges are tobereleasedlaterthisyear, Grand Prix MOM racing with gear changes, cr eh noises counter 88.75 'includingTankBattle,Huntthe Sub andTarget.The SUPER WIPEOUT - E9.17 + VAT. DIGITAL MULTIMETERS MAX 550 550MHz 6 digit pocket counter . console comes complete with two removableaystick DM236 Sinclair portable 31/2 digit LED 104.00 10 different games of blasting obstacles off the screen. 56.50 SOO MHZ Prescaler for player comrole to enable you to move in al four directions PDM35 &leder, Pocket 31/2 digit LED . 36.50 STUNT RIDER - E12.111 + VAT. DM350 Sinclair 31/2 digit max 50 or max 100 40.00 lupidowninghtneld and butt into these Joystick canna are 78.50 Motorcycle speed trials, lumping obstacles, leaping various DM450 Sinclair 4./z digit with 10 amp range PFM200 Sinclair 200M Hz ball serve and target fire buttons. Other features include 1°7.95 Pocket Counter 8 digit 54.50 rows of up to 24 buses etc. (3000 Probes 15.95. P /4.00. DM Nicads 7.95. Cases 8.80) severaldifficulty optionswitches, automatic on screen Bench Portable 31/2 OPTIONAL P/S 4.00. NON -PROGRAMMABLE TV GAMES digit LED. Resolution1 s A / 0 tmv / nector Pack. PFM200 E9.95 . 001ohm . digitalscoring and colourcoding on scores andballs. SPECIAL PRICE NOW E59.60 c72I6R. 10MHz 8 Digit Lifelike sounds are transmitted through the TV's speaker, LMMI00 Lascar 31/2 digit 2A LCD Bench 0.1%.. 6 Game - COLOURSCORE II- E13.50 + VAT. - "At. Panel Mounting 55.80 simulating the actual game being played. LM2001 Laster 31/2 digit 2A LCD Hand 0.196 51.70 LM200 Las., 31/2 digit 2A LCD Economy 0.5% 43.40 0216RP. 150MHz version Manufactured by Waddingtun's Vtdeontaster and 10 Gams COLOUR SPORTSWORLO 122.50 + VAT. ME502 31/2 digit 10a LED plus transistor tester .. 68.25 guaranteed for one year E43.96 MULTI -METERS - GENERAL PURPOSE & ELECTRONIC Multi -Range Instruments featuring AC/ DC volts. DC current. Resistance Ranges (T M3 AC volts only). some with AC current, etc.. Th1111 incredible 120 Range Electronic Muhl -meter* 172.50 STAR CHESS - E55.09 + VAT. TM3I1 AC Micro voltmeter 3MHz >4 Megoher (large scale) 196.75 PLAY CHESS AGAINST YOUR PARTNER. TM3A AC Micro vohmeter 3M lit >4 Megohm 149.50 3110TR 100k /volt. 23 Range (plus transistor checker). Large scale using your own TV to display the board and pieces. Star 34.96 7080 20k /volt 26 Range. Large scale 26.95 Chess is a new absorbing game fur two players, which will 7081 50k /.1t 36 Range Multi -meter, range doubler 19.96 intermit and excite all ages. The unit plugs into the aerial NH65 2kv 10 Range Multi -meter 6.95 socket of your TV set and displays the board and pieces in NH56 20k /volt 22 Range Popular Multi -meter 10.95 LT101 tk /volt 12 Range Pocket Multi -meter 5.95 lull colour for black and whitel on your TV screen. Based on VA360TR 201, / von 19 Range Multi -meter plus transistor check . the moves of chess.It 13.96 adds even more excnement and AT205 504 / volt 21 Range Multi -meter 24.95 interestto the game. For those who have never played, ATI 2k /volt 12 Range Multi -meter Deluxe 7.95 Star Chess is a novel introduction to the classic game of TMK500 30/ volt 23 Range Multi -meter. with case 22.95 chess. For the experienced chess player, there are whole ATI020 20/.11 19 Range Multirnmer with transistor tester Deluxe 16.95 new dimensions of unpredictabilny and chance added to AT2050 50k /.1t 18 Range Deluxe Plus transistor checker 28.50 AT210 100k /volt. 21 Range Multi -meter Deluxe . the strategy of the game. Not only can pieces be taken in 29.95 AVO 8s and a large range of replacement_t Weds in stock moves, bin each piece can also exchange rocket fire with as opponents. The unit comes GENERATORS complete with a free 1BV mains adaptor,full instructions GENERAL EQUIPMENT TGI52 Sides 3Hz 300kHz 5 Ranges and twelve months guarantee. 1E250 Signal Injector 4.95 TGI52D .92.00TG1521Ilm TE7 Signal Tracer AF/RF 9.95 (wale meter) .....113.55 CHESS CHALLENGER -£00.05 + VAT SWR50 SWR / Power Meter 13.95 TG200 Series RC Oscillators Sine/Square output. DRS10 36 Value Rests. Box I Hz- I MHz 12 Ranges PLAY CHESS AGAINST THE COMPUTER. 3.95 TG200D RP124 0/24v 0/1 amp P/S Stabilised 42.00 124.20 The stylish, compact, ponable console can be set to play at TG 2000m (with meter) 149.50 RP324 3 amp version . .... 54.00 seven differem levels ofability from beginner to expert RP2305 0/30v 0/1 amp. P/ S Twin 1320013mA (meter 8 fine control) . 165.25 4001 Digital Pulse Generator 0.5Hz-5MHz.. includng"Mate it two"and "Chess by mad" The computer Meters 85.00 105.00 will only make responses which obey international chess TR1000 Transistor checker in /out circuit11.95 MOD93 Signal injector 2001 Function Generator-Sine/Square/ rules. Castling, on passant, and promoting a pawn are all 8.65 Triangle/Ell 56.00 C3022 Transistor /Diode Checker . 19.95 included aspartofthe computer's programme.It is 3101 Clamp Meter 0/1 K ohm. 0/150 5E12030 (11F) 6 bands 25001z-300MHz 49.95 Possible toenter any given problem from magazines or 300/600 AC volts 0/300 amp 32.95 6052 PAL VHF /UHF Colour Bar Generator newspapers orahernativelyestablishyour ownboard MIMING CHESS BOMO TUTOR SWR40 /9 SWR & FS Meter 10.50 250.00 SWR10 SWR Meter 10.95 A0781 (Audio) sine 19Hz-220Hz square 19Hz- position and watch the computer react. The posnions of all E17.17 + VAT I/VIKHt 61.00 pieces can be verified by using the computor memory recall MS319 2,100 Watt Audio Wan Meter 13.95 ARF300 (11F.Audio) 11311,200MHz A specal bulk purchase of these amazing chess teaching '500V Megohrneter 500 Megohms 61.00 71.50 button. machines enables us to offer them at only C19.75 less than '21/2 Amp Variable transformer 21.95 PROTO BOARD IN STOCK Priceincludesunitwithwood grainedhousing,and half recommended retail pnce. The electronic chess tutor is KITS PR 6 9.20, PR 100 11.80. Staunton designchess pieces. Computer playsblack or a simple battery operated machine that can actually teach DRILLS AND DRILL KITS SEPARATES EVP300 5.95, EOP600 white and against itself and comes complete with a mains anyone to play chess and improve their game right up to 9 to 12 volt Operated. Ve" max 8.50, EXP350 3.45, EXP650 3.96 SMALL DRILL with collets 6.85 adaptor and 12 months guarantee. championshiplevel.This machineisnot onlyfortotal MEDIUM DRILL with 3 collets... 9.90 LOGIC PROBES AND MONITORS beginners but also for established players wanting to play OTHER CHESS COMPUTERS IN OUR RANGE INCLUDE SMALL DRILL with 20 drills/tools 13.95 LT2000 Economy Probe 10MHz 6.95 better chess. Unit contains the electronic chessboard with MEDIUM DRILL with 20 drills/tools 16.95 LMI Monitor orcuit powered 33.00 .CHESS CHAMPION -6 LEVELS E47.39 + VAT. 32 chess pieces, a 54 page explanatory booklet and a set of MAINS Eliminators .. 9.95 LPI Probe 10MHz 36.50 LP2 I 5MHz CHESS CHALLENGER - 10 LEVELS -1138.70 32 progressive programme cards including 6 beginners VARIABLE Speed ... , 13.95 20.50 12 volt Vi" Heavy Duty Drill 12.50 16 Pon IC test clip + VAT. cards,lficheck mate positions,9 miniature games, 5 1.95 MAINS DRILL with tool set 19.95 1 BORIS - MULTI -LEVEL TALKING DISPLAY openings, 3 end games, 28 chess problems and 2 nosier E163.04 + VAT. PIEZO HORN games TV SOUND TWEETERS High quality TV sound from your Hi-Fi. i, Up to 100 watts eachNo .over DRAUGHTS COMPUTERS Simply plug into aerial socket of your FM it 14 reqd Only 4.95 each tuner. £8.50 (UK P&P 50p1. Flared Horns 6.50 IF Midrange Flared Horns 9.50 CHECKER CHALLENGER 2 LEVELS E43.00 + VAT PLAY DRAUGHTS:CHECKER:3 AGAINST THE COMPUTER PRICE INCREASE AS FROM 1/6/80 (UK Post Free) 4 LEVELS E711.00 + VAT dimmes., SPECIAL 611LX PURCHASE The draughts computer enables you to sharpen your skills, -41(15 IR 10+10 wet Improve your game, and play whenever you wantThe Tuer/PapIllier. 111W/LW/SW/Sleres FN. Sapplite computer incorabrates asophisticated,reliable.decision u lea my Is mutt WU. making microprocessor asasbrain.Its hqhlevelof f21.1115 P&P U.50 thinking abety enables it to respond with its best counter ill IN STOCK NOW -- '.f _I moves like a skilled human opponent. You can select - 4. , , nlience or defence and change playing difficulty levels et Large ranrangeof ' 4 ,''' speakers and kits. TM3 any time. Positions can be verified by computer nteniOrY public address recall Machine does not permit Riegel moves and can solve - equipment. set problems Computer comes complete with instructions, microphones, mixers, rains adapator and twelve months guarantee. TM 1 1 TMK500 security systems, intercomms, ham CALL IN AND SEE equipment See FOR FREE BROCHURES- SEND S.A.E FOR YOURSELF catalogue For FREE illustrated brochures and reviews on TV and chess games please send a sian vett addressed envelope, and stare PRICESCORRECTAT 1/6/80 'FM which parircidar games you require information on Callers welcome at our shop in Welling demonstrations daily - open from 9ani 5 31.1pri Man Sat I9ani 1pni Wedi CATALOGUE To order by telephone please quote your name, address and Access:Barclaycard number Postage and Packing FREE AUDIOELECTRONICS , 301EDGWARERD.,LONDONVV21BN AJD DIRECT SUPPLIES LIMITED, Dept. ET7 102 Bellegrove Road, El)ENVELOPE 01-7243564.OPEN9-6,M ON-SAT. P'c°0-,,:ti,I,ii,no'r6,74ov4 Welling, Kent DA16 3LID. Tel: 01-303 9145 IDayl 01-850 8652 lEveningsl ALSO AT 248 TOTTENHAM COURT ROAD W 1 60 ETI JULY 1980 QUANTITY PRICES - SAVE - SAVE - IMMEDIATE DELIVERY (incl. VAT) NEW STOCKS BELOW MANUFACTURERS' MARRIOTT TAPE HEADS Quarter track PRICES. Postage & packing add 50p per order Per 10 SN7414114 IC 50p 441. MULLARD Type Each es. 100 £3.00 E25.00 B CD DOCI0181 Decoder -Driver 10 for 44p XRPS 1813/ Replay E35.00 XRPS3613/ Replay E4.00 Icy 40p u. 1.000 for 3Sp r. E2.25 E20.00 BandIt'ssoeasy andit tidy with the Easibind DISPLAYS by Hewlett-Packard Seven segment 11517631/2track E11.00 your copies away. Each DL707 (5082-7750) 95p. Common anode half XES11 Erase E1.25 bindertofile ,nch red display brand new in maker's cartons 6 MAINS TRANSFORMERS all 200/250V IN binderisdesigned to hold approximately for ES. 50 for 70pes. isattractively bound TV BOUND. High quality sound through your Price twelveissuesand hi-fi Simply plug into your aerial socket. E8.50. as Type Current Size 100m /a 11/2 x 11/2 x11/2 E0.95 and blockedwiththe ELECTRONICS reviewed Popular H i-Fi 12V £1.35 URROUGHS 8 DIGIT Panaplez calculator 12V 100m/a 114 x 11,4 x1,A TODAY INTERNATIONAL logo. display 7 segment 025" digits Neon type with 300m a e 2x2020.50 6-0-6V E2.95 red bevel socket and date £9.95 r. 10 for £17. 12V 2 amps 3021/2021/2 Price U.K. f3.95 including postage, packing HONEYWELL PROXIMITY DETECTOR inte- STEREO CASSETTE TAPE HEAD. High quality and V.A.T., overseas orders add 30p. Why not gral amplifier 8V DC E3.5044,10 for E30. replacement for most machines record/replay MULLARD TBA800. IC audio amplifier 915pse, with mounting bracket E2.95. Foster place your order now and send the completed 10 for ES, 100 for £70. DYNAMIC MICROPHONE. Low imp coupon with remittance to:- RCA CA3089. FM IF £1.50, 10 for E12. insert £1.45, 10 for Ell, 100 for £100. RCA CA3090ACL FM decoder E2.50, 10 for TWO GANG MINIATURE VARICAP TUNER EASIBIND LTD., 4 UXBRIDGE STREET, £20, 100 for E175. 500pf with tuning knob size 3 x 11/2 x 11/21n BU205 TEXAS, £1.50 vo, 10 for E12, 100 for £1.25 so, 10 for E10. 100 for EU. LONDON W8 7SZ. Tel: 01.727 0686 £100 per 1,00055pea. ATES U14552 AUDIO IC AMPLIFIER 14 PIN Please allow 3/4 weeks for fulfillment of order. TEXAS 10 WATT I.C. AMPLIFIER. SN76018 DIL 300rn watts 55p ros, 10 for (4.50, 100 for 5 -pin package. E1.25 E35, 1.000 for 30pea. B U208 T03 Texas TV power transistors 0.75 GENERAL ELECTRIC 2 -c 2 watt IC stereo audio mr, 10 for 05, 100 for E120, 1.000 for El44. chips with circuit & data £1.9544. MC131017-811176115N FM stereo decoder RCA CD4029AE 16 pin DIL presettage up down it's easy L1.20 AA 10 for El 44. 100 for 115p u. counter 85p ureh, 25 for £15, 100 forE50, MULLARD AD151 -AC1162 Matched pairs Pair 1 000 for E355 On anti static tubes of 25) wth 80p 10 pairs EA 100 parrs C150. UHV TUNER (preamp) with BF 180 55p uch. Cartons of 600 pairs E250 EX STOCK Built on PC board 2 x 2in (sold without data) 10 Easibind Ltd,4 Uxbridge StLondon,VV87SZ. RADIATION DETECTORS Quartz Fibre for (4.50, 100 for E35, 1.000 for E260. Dosimeters Pen type with clip with lens and scale HELICAL 10 TURN POTS BY M.P.C. 2 5 watts Nat. Giro No. 5157552. Current list price E25 0-58 in new condition tested 5% tolerance type MM1OS British made 100 set ready for use only E5.95. 220/470 1 k / 2 2k /4 7k /47k. All at our price r TV TUNERS by Mullerd UHF 38 mcs rote £1.954s. Manufacturers list price C3.80. x 214 x l Y. 62.504410 tor E20. 100 for CASSETTE TAPE MOTOR 12V with transistor (175. 500 fOR E750. 1,000 for E1,250. voltage regulator panel E2.50. Order Flinn MULLARD TUNER MODULES with data WIRE WOUND MINIATURE M P C controls LP 1171 combined AM FM IFstrip E3.50. LP BRITISH MADE M r 213 ALL AT 60p oull ELECTRONICS TODAY INTERNATIONAL 1179 FM front end with AM tuning gang used with LP1171 E3.50. LP1171 and 79 pair £5.75, 47 ohms 2 2k Per 10 50pea. 4 7k I enclose p.o./cheque value 10 pairs for E50. 220 CA3085 RCA POSITIVE VARIABLE REG. 470 10k 5volt 100m amp variable 18-24) 55p4a.10 for 1k 47k for binders RELAYS mm open type 9v change over 85p. ES. 100 for E35. MULLARD LP1157 AM tuner modules with P 10 75pea. P10065p. P 1.000 50p45.Minn Years required 10 for E20, 100 for £175. 9120 2p over 200 ohm E1.20. ("molt E2.50ea, TBA625 ATES voltage regulators 55p u, 5 volts LU AAAAA HONE RIBBON MIKE E1.50, pre BLOCK LETTERS PLEASE amp on chassis 3 x 2x 1in 10 for E12.50. 100m ramps (10991 per 10 E4.50 TAA6618 (14 pin DIL) IC TV sound and FM 16 PIN low profile DIL sockets 12p, 10 for El, Name amplifier -detector by ATES on p circuit board with 100 for Ee, 1 000 for Sp so. other parts Complete with data & connections THYRISTORS Motorola 2N5061 08 amp 60 60p. 10 for ES. 100 for 40p os. volt 19p, 10 for 1Sp on, 100 for 13p u, 1.000 Address DRYFIT RE -CHARGEABLE BATTERY. 6 volt for 1 1p ea Size 6" x 31/2" x 11/2" at half price ULTRASONIC TRANSDUCERS 40 KC 's 4 5 amp /h Pa, if £2.95, 10 pairs at E2.50 pair Brand new £7.50, post 50p V All mail to: 404 Edgware Road 71.1.M111,,,,,,c,,,,,A:10 London W2 England or,""""11,44, Date 5 HEW Phone 01-723 1008I: Registration No. 307469 ea EXPORT ORDERS add 10°. for carriage TELEX 262284 TRANSONICS. REF. 1400 I. SUBSCRIPTIONS This year we present a new twelve -part, non-fiction series-ETI 1980 available from your newsagent every month. Forget to buy it this month, or is your newsagent sold out? Why worry when ETI gets to the shop? Sit back and wait for it to come to you. Take out an ETI Subscription. For only £10.00 we'll send you twelve issues of ETI PLUS A free copy of ET! 1999, a chronicle of future timesincluding the first report of World War III. You've never seen anything like it before To claim your FREE ETI 1999 (and a years'supply of ETI, of course) send your PO or chequedirect to ETI Subscriptions MAP Publications PO Box 35 Bridge Street Hemel Hempstead 61 ETI JULY 1980 Herts. Freepost III FREEPOST ON ORDERS ACCESS G1111Birmingham is VAT INCLUSIVE PRICES 61 B19 1BR II ADD 30p P&P ELECTRONICS CHEQUE ,1....141&-miMnft4 noidl nAndi% 24 HR PHONE ANSWERING SERVICE ALL PRICES IN PENCE EACH UNLESS OTHERWISESTATED CAPACITORS Minrettp Low Value Order Code Poly..... 0147191 Lead Order Code RESISTORS Electrolytic Axial Leeds Ontw Cade PoluNerene. Amel. t Tol ...V DC Wp. Cap 424 Dm.. Tenn. C280/352 0/7!. Order Cod. Cererng 004, Rad.. Low 0. 100V DC Wk.. Cap 352 Carbon film. hod -10% 9 4014 Tol. Lv90100.7 MV a.. C.0 632 Mad* Typ.. 10.299 Nen C.. 380 Cererrue Mau 9409. PAW 9 1000 DC W 8. OM 630 0 2104, 024 Yawn 100 10M, 51 Tor 2 wren 9F V41.4 16 26 Value 100/100 WW1 10/Veluel144. 905 4/9 es Cerernoc Pleto ROW. Me K. 63 V DC NM 059. 012 Va14e7 11404147. 1017 To1 1.0 Cm 679 3690150/100 Mull 10/VPue1 0147 ROW Value oF 252 SOO SU BOO 1.6 Ve119 pF 001 .1 7 0 2.2 424 832pF 424057430 OF 414 629 POW Film Flood 0015 .16 10 3.3 100 IS 10 27 8 0.69.124 Ve170, Slivikt 2/ Tot. 9.000400/100 15911 109999 7.2 0022 12 9 11 979 MR30 4.7 120 le 17 29 2.60. 012 061..., 101.117K. 51 79 19.0.0800/100 9.11 10/7/69.1 1.6 0033 13 11 90 P957 11.9 150 IS 29 COM .4, 14 Verua 10 1/ 1110 IS 18 31 2.2 ONO CO 17 11 11 220 22 31 9 Metal Cileze, Fixod 01 1.0 21 2.7 270 20 27 11 22 17 015 1.6 0.59. 024 Vatuw, IM.33M, 59 To. 15 ownBOO/ 100 /04/7 10/5..1 194 v1437 33 3.3 330 20 33 45 20 022 2.2 value 3.9 300 26 47 11 13 20 39 50 033 68 4.7 470 20 Skeleton Newts. Minimum 6.6 660 00 100 13 20 068 E3 Van.. 1000./U. Lon. Idertmel 0007l,.,0 8 Mn Prow/ v 150 OW O 31 20 al.. 03 geiues. 10041109 Lon. 140086091 eneurn.ng 11 Prawn 5. 11.2 870 20 220 13 20 38 V olu 10 WOO Tantalum lad Ord., Cods 330 30 40 20 12 7203 20% 194. Cep 041 of vo774 Skeleton hews, Stan den:I 470 32 30 15 1500 0 37.1. 03 04197, 10004917, Lrn7.9170.771 00407, 11 Sul P. 880 21 30 39 20 V719. 10 16 28 X le 1900 0.300. 03 041594, 100114517, Lon 005.0.91 006006.9 11 Std Preset N 7000 26 59 20 0.1 22 7700 20 Ve1u4 1500 35 30 0.22 11 27 2200 42 2700 20 947 11 Potentionoto, Rotor" 33 3300 20 0.50. El Volum. I K 27472 Lrn 13 313 Ro Poo CO 39 3000 20 2.2 11 13 0 2575. 03 Yeluw. 407.2042 Log 39 Re Po. Lop 47002s 4.) 12 IS P C B Conmonnts 55 5800 V.I. 25 70 13 16 18 22 Potentiometer, SOON Bei 68 SOO Oalo Pen8.311 J. 96. 09.. Nn 332C 25 72 18 82 ODIN. E3 VIum, 2K24700 1,5 46 SI Poi Lon 0705 25 22 0.29N, 53 Volum, 100 / 1000 L611 45 S Poi Log VW. CPAOS [SUFFERED, 74LS /914001 22 1111.1044 105 LINEAR SEMICONDUCTORS 1E14512 136 7415130 19 741383A /474001 106 7413174 141 7415373 173 22 14.4046 133 11314514 741501 CA3048 84 15914 753705 10 .113 19 741585 04 7415175 119 74.374 I O 01021 12 If MI5 29 HEN002 22 11..7 91 173 06301173E 77 991301 11114315 374 741502 19 74110 5 253773 297 11 0/974006 39 7415161 306 74.375 117 5C154 1,50 119 NE1404.3 57 11E14316 127 741303 CA31300 90 1%4002 5 19 741590 59 74.190 117 253619 22 S C11141 12 IFV51 17 .114007 22 0E14050 7413378 155 57 0E14317 4715 74L504 CA3140E 48 154004 7 253820 39 20 27 741392 76 7413191 117 7413386 56 10272 11 07152 0114008 100 MEF4051 87 11554516 CA31890 293 154007 118 741305 27 741593 76 7413192 119 74.390 9 253904 S C2121 12 SUMS 262 0104011 22 E74052 196 LM301AN 11 Po 11E4519 sl 741500 27 1541411 4 255457 39 50 H014012 74.58 82 7416193 119 741.93 196 11C214 11 00139 22 11E74053 Po Huss2o I/O 741309 1743395 70 155402 15 255459 35 27 741596 126 413194 161 7415395 207 002141 12 00020 21 ./1574011 57 1.7439051 104 nitro. 62 11114521 235 741510 19 2572184 31 40573 7413107 41 741.319. 119 74.00 143 N 5C547 13 CLIO. 2850 0E71014 105 19.067 75 NU.. 124 14/511 1171381 AN 103 2573039 26 7413109 45 4.196 tai 21 AD161 42 50391 11 MP, 102 36 /1119315 100 NE1.68 22 INN532 1039035 15 I. 741312 15112 45 701197 132 Plessey I/C's 252893 45 40182 02 BC549 12 13A91 8 ..1114016 57 9174069 21 MF74534 0340317 756 638 41313 743113 74131. 2. 31.440 31 2529266 13 90101 14 00357 15 0026 118 ..10e0i1 100 14114070 22 111.539 138 NE531 131 741314 7435114 701241 2. 51445 182 270063 19 acme 14 0007 15 0C33 474016 100 H114071 23 0174543 194 505361 250 74315 16 703125 53 7413242 206 01.014 245 15.4064 55 e clOec IS BC 0 15 1111/310 48 PEe4019 ME14072 23 0114553 98 741320 505555 28 14 10 7415126 53 74.20 706 31.813 245 353055 55 110100 80777 15 1.11732A 0714020 112 Mei 4073 23 0E7056 VI 505685 56 74.1 26 74.132 JB 703244 200 SUMO 369 253055 O 07090 19 130131 39 TONIIC 16 P114021 107 11(e4075 23 11514557 NEMO 71 Gtau IS6 TAD 741322 26 74.136 70251 117 01.021 389 95 80109C 20 010732 39 TIP420 16 0E1.22 103 14.4076 130 004385 122 7465705 485 74.28 15 74.138 7413253 117 01622 910 293442 155 S C148 10 50139 39 TIP2955 15 HIF4023 22 NEF4077 22 5414724 14 N05715 505 70330 19 7415139 74.57 117 01024 342 293702 9 50191 10 O 0140 39 TIP3055 60 0414020 (2 XE74076 23 NEV.. 113 RC41313 146 253704 14002 27 7415153 es 741.3258 117 01030 232 9 S C177 17 1311/190 333 11343 36 7414025 11114001 23 111740098 92 TB/1170S SO 70133 35 793154 191 7413260 29 01640 539 0E7.26 44 7114087 23 0E740106 TDA1022713 Voltage 78 741337 35 7413155 93 741.3261 321 SUMO 245 OPTO ELECTRONICS POotoreostow 0E14027 57 9.4005 80 1.19 .140160 74.38 35 7415156 7415266 54 511510 177 71)4103411 239 Regulators nIF4028 LIVOI Emitting Modes, Indowdual 01.12 95 4086 80 111i40161 741340 27 71011CP 04 7413157 03 741.3273 43 011611 177 1030904/91 119 95 PEn4029 113 //.4093 60 torrolvi 149 710114C5 165 125' I3mm0 Rad 16 C0054 01.15/ 741342 60 7411158 97 74.283 17 011613 177 6.4723014 42 P5140.10 PIV094 210 149 1./671105 Green 10 MEW. 74.51 27 7413160 129 74.293 7 511521 239 20 LIAMOSCU 70 C0095 Phototramistors P514031 Niel. 208 P1140174 149 199741C7 31 yam. 20 C0097 741S. 27 7413161 117 741.3.3 19 01113203 LIA71112CU //174035 ..10502 27 711 Oa, 20 114 NEG40175 149 70355 15174804 39 Pane, Mountrng Cho ro Surt 3 LED] C165 27 7413162 144 74.298 29 517030 177 UA7BISCU 78 O 1.25 195 /410 714 i101T11 9371 35 74131.3 117 703365 21 511640 205 97 2 '15991 195 HEM 66791206 flee 16 C002. B PX29 703164 119 74.366 21 511641 205 40090 C407.033 UA79I5CU 97 .1E101 22,.0010 COND4 7415170 220 701367 21 0113640 270 .112188/62071 6A713106CS 30 91.3 Ot1010.11113141 OlEY4 20 C0098 741.5173 7413365 21 ONO 475 19317e91 137 9 °A/1.12o5 35 aanel 11.1ounbne Cbp to law S 1E05 Cho 7C0020 165 Mono BOX. - ODD Industrrol Mould ngs SWITCHES Madded 50..70 Crew 0.7.9149791 L. Order Code MAINS TRANSFORMERS Order Code ABS Boo. CNV 5.45 5.95. .00 Lro 10 Or 041 Moon. TOON - 1.100S5..11 VERO ELECTRONICS PRODUCTS SPOT 900011(187,..1107 50 tonnettee wr.es or 71 200 210694 Order Cod. 67 SW 01011 649119 No pore mde .61189. 'en. 1112 W112 1337 SPOT 3 75" 6 0.7en 79 2002101(0 99 Caw 5103003 09 C/011 01 SW 841071 himat.e. 0.220 2400 1750 000 050 131 Cam 8102005 09 SPOT 0.010 890 To Comt9 90 SW 001041 2 S'' 1"I" each 00,6500 49 15/ 55/Poor 20021076C 1190 01 10 000 773 Co.. 5152005 OP 5POT 3.6.913.9 90 SW 847057 130 - Clamp Type ConNoucbon 235.66 3 75" 5".1 e.00ard 68 200.210789 5.82" x 20. p.tch DO 0 IP Board 135 200-210845 PO10 nom with 5797141 L914 SPDT 044 84 3N3.7057 ApoN55 IBA Resulabon F C 5.1136. 0035 Spot en. Cull, 107 Ramer] Top Ilos OPOT 99 50 842011 201210130 0.45V, 0.4 SV Seconds. en P.n Inemban Tool OPOT C/011 111 Sw 0.42021 790166A or 040 Noe pm 147 203.210150 geso CNN Bron 54996 10071191 03V. 0.60 DS 7.0, 040 11001 lown Alven.nown Top Pen. f.n.940 010 DPOT Double On To Genus 123 000 342047 00 44/065 2013 210870 010T 0120.0.12V SS P.m 04011001 44/Poor Order Coda ¬.. To Centre 123 SW 7.2051 120 200110178 DOI,. Del 0156.0.150 I50 0111100.11 6.711 son, 2wrra. 25.97091 454/0rt 100 2734103410 1115 055 079 112 Cave 8974003 OP 716 00 1347031 020V.0200 200 Vrown Cowes 1251 10111/1505 20171339 1111 071 13412 ISO Caw 5991004 OP Minosture Pu97 -C & 10.9 121 109/P9a 200-21340C LISI WO 053 208 Crow 01047305 00 20VA Clamp TYPO Convoutbon 300 Oiecert Boxer SP Pug To NAN. Momentary 82 SW 8531 SP 040 To Break. 1,10110, 62 Sw 8533 ,0. 16* 711401116on f C 70 941 WO Owcast 100 and 0149411 1,0 Ilmtoonks Aluomintoon Ilex And Lad on New. am.. C. 5V 0.4 55. Smonclanm 7/ em700 45 105 Owlet Cede D.I.L. 501.9. 0110.046 60 1.0,2401 Type N. I C V 12 1113 cm 031 174 Case 5105003 NA 0120, 0126 120 mem.. Type r0, 1 x 7066 10 5'016 20 Dm TO 1152 012 050 216 Pm Low Prolde Socket Ton 12 D1L SOT I D150.11150 indomann 100I110, 1 1.03 7 2'DVI 26 5,70 163 Caw 11155005 54 14 Pin 16.965111eS9aet T.n 150 11920113 061 334 Case 51050011 NA 011 SKT 0.17 5%1.0/12 50 175 Indextdua TYPO 10r 1 TO129 1 C 26 590 104 II Pro Low Prof ge Socket Tor 16 OIL SKT 16 0205.0.206 200 M00rodua1 Ty. N. 1x 10220 17C Ye 26 Smic TV5 G.M. T. ELECTRONICS KITS. PUBLIC ADDRESS EQUIPMENT FULL TELETEXT KIT A55 20W AC/12v0C MOBILE AMPLIFIER 69-00 (Free-stonding unit- no in ter. 1connection to T .V.) E199-90 A56 50W AC/12vDC AMPLIFIER 0117-30 TELETEXT DECODER REMOTE CONTROL KIT (For wiring into existing television) £135-90 A70 I75W AC/24vDC PROFESSIONAL AMPLIFIER 0276-00 PAL ENCODER/MODULATOR KIT E 22-90 L78 20W WEATHERPROOF HORN SPEAKER, 8 OHM A. LINE £ 41-40 DOPPLER RADAR ALARM KIT E 44-90 L83 16W MEGAPHONE (SEPARATE MICROPHONE) £ 69-00 F .E .7 . POWER AMPLIFIER OUTPUT MODULE KIT 27-50 L110 40W CABINET SPEAKER 8 OR 16 OHMS (SPECIFY WHICH) (c/w block 'vynide' covering, metal corners and overall cover) £ 89-70 ONE AMP POWER SUPPLY MODULE KIT - FIVE VOLTS £ 6-00 M2) UNI-DIRECTIONAL ELECTRET CONDENSOR MIKE, 600 OHME 19-32 ONE AMP POWER SUPPLY MODULE KIT - TWELVE VOLTS £ 7-50 M30 BALL WINDSHIELD DYNAMIC CARDOID MIKE, 600/50K OHM E 28-98 MODEL INERTIA CONTROLLER MK I- SLOT RACER £ 30-00 MI04 SIX CHANNEL STEREO MIXER AND PRE -AMPLIFIER MODEL INERTIA CONTROLLER MK II- TRAIN (HAND UNIT) E 25-00 (accepts high and low imp mikes, and hos RIAA input) E 62-10 MODEL INERTIA CONTROLLER MK III- TRAIN (CONSOLE UNIT) E 25-00 M124 FLOOR TYPE MICROPHONE STAND, EXTENDS TO 60" E 14-49 62 ETI JULY 1980 NEWS RAVEN ON Dave Raven of Metac Electronics reports on arevitalised Swiss watch industry and the programmer catastrophe. To make a fortune in electronics is not an unrealistic ambition in the 1980's. It compares favourably with the earlier successes of entrepreneurs at the turn of this century, making fortunes from the boom in bicycles and then motor cars. Similarly_ young dynamic com- panies have emerged all over the world feverishly setting up new businesses that are associated with the enormous boom in the microchip industry. At this time of year students face a major challenge in the examination room which they perceive as directly affecting their future careers. With the right results at hand the next task is to start selecting a suitable job with prospects for the future. If electronics and cash are the big motivators, then much thought must be given, since some areas of this industry will in the next decade be prepared to part with larger sums than others. Supply and demand is still the order of the day, even in science, and if cleaning ladies are in short supply then they will command a higher salary than say a PhD Physicist. The increasing popularity of microcomputers has placed industry on a direct collision course with a major obstacle. With some careful planning now our intrepid students may find this rich in rewards by the mid 1980's. A software crisis large enough to slow down the whole The new quartz analogue watch modules now look very similar to their digital counterparts. Typical thickness for these models is about 3.9 mm. business of microcomputer expansion is looming high Swiss companies have a great deal of experience in producing these and over the horizon. The simple arithmetic which can con- it will present a major challenge to Japanese and Hong Kong assembled firm this shows that although the numbers of micro- watches. computer designs is increasing by 30% a year the cost of advanced chips the military need and to stimulate the implementing the designs will double. In the USA it has development of "integrated systems". Other American been estimated that by 1990 they will require at least companies such as Intel will spend up to 150 million one million software engineers and since the electrical dollars on capital equipment in 1980 as part of their "in- engineers graduating at present can be numbered in only tegrated systems" programme. For the next decade or so thousands it is described as a "programmer catastrophe". I sincerely hope we don't have cause to fall out with the In addition to the limited educational system which Americans since, as the decline of our own ability to is seen as a further major contribution to the potential fabricate microcircuits continues, we will be less able to software crisis, the cost of developing software is also compete in the manufacture of industrial equipment seen as having serious consequences. The cost of pur- without supplies of devices from the USA. chasing the hardware is expected to change little since Whilst other major industrialised countries are sink- this reflects the increased memory capacity of the micro- ing cash into research programmes the UK Government chips. However, software costs have risen dramatically. have just announced that they intend to resist pressure The alternative open to the semiconductor giants is to for further state aid. The micro -electronics Industry Sup- develop more complex microchips which contain soft- port Programme has been cut (not increased) from £70 ware packages within. Thus a programmer can reduce million to £55 million over a five year period. Also the the time taken to assemble his software. This is similar to microprocessor Awareness Programme has retained its the developments of earlier circuit designs which have budget of £55 million over a three year period. This total progressed from single discreet transistor design to cash is less than one medium sized USA company will designing with complex blocks of circuits. The cost of spend on R & D during the same period. As for spending these new developments are enormous and only a few £55m on making people aware of micro -electronics I very large manufacturers can undertake projects on this would have thought that regular reading of the elec- scale. tronics Press in the UK and USA would wake people up sufficiently to what is happening. This would of course Microchip R & D be a lot cheaper and the real spending should be done on In the USA the Department of Defence have decided making devices. I suspect that most of this money will be to implement a 200 million dollar programme for the spent on making up for the lack of technical education development of very high speed integrated circuits and ignorance that results from the narrow curriculum of (VHSIC). This money will be granted to companies in the schools and universities where many of the nation's private industry to make it easier for them to build the leaders spend their youth. 1110.- ETI JULY 1980 63 NEWS: Raven On It is easy to grow cynical on matters which are not every day problems to government. However, I am per- sonally convinced that urgent attention must be given to our country's future role in electronics. The solution to our avoiding a software crisis and indeed an industrial crisis in Britain lies here within our shores. We can very soon find plenty of aware people if the cash is available to support them. Personalities like Derek Roberts who currently heads the GEC Hirst Research Centre and John Bass from Plessey, to name but two individuals, must have quite a lot of experience in organising microchip development between them. Instead of carting parties of TUC officials to the West Coast of America in search of awareness about how microchips are made they should New generation of quartz LCD take a bus to Towcester, Swindon or Wembley. Here Watches. Sabre Alarm Chronograph they will see just as much technology and its all British. uses standard watch cells and Forget Inmos factories in Colorado Springs. How about measures only 3.9 mm thickness. setting up something twenty minutes from Heathrow Air- port or at least within easy distance of some of the best popularity stems from the neater, cleaner looking design microcircuit designers in the world, here in England. and also this new slimline case, which dispels thecause for much complaint in the past. Also quite a number of people,particularly those over acertainage,ex- Swiss watches return perience difficulty in seeing the digital display without spectacles. My additionalsuspicionfor the strong at Basle Fair. emergency of quartz analogue was that the Swiss were The annualeventoftheBasleFair,heldin probably struggling to keep up with the current level of Switzerland each Spring,incorporates probably the high technology in the digital quartz. This was also largest exhibition held anywhere in the world for watches quickly dispelled, I am pleased to report, since the elec- and clocks. This very traditional fete is the assembly tronic varieties were every bit as advanced as anything point for watch buyers from all over the world who place yet seen coming out of the Far East. orders for their full year's requirements. Exhibitors at the Quartz analogue watches deserve some further men- show are almost exclusively from the Swiss Industries tion in particular because of the technical achievements with just a smattering of other European companies. which have occurred during their redevelopment. The Walking through the lavish exhibits of such famous Swiss have of course a long tradition in the manufacture names as Omega, Tissot and Rolex it was very hard to of traditionally designed watches and they also havea believe that the Swiss watch industry had just emerged large number of credits for new development work in the from five years of nightmare competition. This ofcourse manufacture of watches. It was here that the thinnest was a result of the enormous increase in quartz elec- watch ever made was produced in 1975 (1.2 mm). Its con- tronic watches during this period. ception was quite revolutionary and was described at The sudden arrival of LED and then LCD watches the time as defying the logical laws of watch mechanics. and the continued rapid developments of microchip This same company incidentally has been takenover this technology produced shock waves which must have past year by one Japanese company called K. Hattori, threatened the existence of many of the. smaller watch who, you may or may not know, own the brandname of producers. Hong Kong, who were at thevery heart of this Seiko. watch revolution, increased their market share in watches On the new technology front, Bulova announced from being a net importer of watch modules from their rather unusual watch which drives its energy from Switzerland to becoming the world's largest watchex- the body's own heat. A voltage produced from the ther- porter and in terms of value of watch exports theynow moelectric elements is transformed through a sophisti- rank third. cated electric circuit to the required voltagenecessary The way in which the Swiss watch manufacturers to operate the watch. On attaining the required level of operate must have considerably altered in the past five voltage, this energy is directed towards an accumulator, years, with a number of mergers and trading agreements which is in effect a rechargeable battery. Theaverage taking place. The saving grace, however,seems to be the body temperature of 37°C delivers at thecase back Swiss watch manufacturers' strong financialresources more than 1000 uW of "heat" power. The power consum- and also their ability to withstand change and rapidly ed to operate a typical quartz wristwatch containinga learn new techniques. tiny batteryis approximately 2 uW. the device that The presentation by manufacturers at Basle for both Bulova has perfected receives from the thermo-generator digital and analogue display watches was ofa very high approximately 8-12 uW. Therefore, the electric energy standard. My biggest surprise, however, came from the produced is four to six times greater than that which is strong contingent of quartz analogue watches. These consumed in operating the watch. models, which Ipreviously thought were extinct, have One other Swiss company in strong evidence was risen once again in quite a different form. The first im- Buler, whose range of ultra slim analogue and digital pression was that this was confirmation of the demise of models will certainly be serious competition for the the Swiss watch industry. Then after closer inspection I Japanese quality watches. The new twelve digit quartz realised how much slimmer and neater these little beasts electronic model from Buler must be the most advanced looked.I was left in little doubt that these will be well module coming on the market this year and will further received in the watch market place despitemy own pre- increase the market share for Swiss -made electronic judicestowardsmechanicaldisplays. I feeltheir watches. ETI 64 ETt JULY 1980 dlo see u-civeSuon and atldoA xsA St:1'1;004171/4 lcFrobes Spend Less J Test More LP -1 Logic Probe LP -3 Logic Probe The LP -1 has a minimum detachable Our LP -3 has all the features of the LP -1 plus pulse width of 50 nanoseconds and extra high speed. It captures pulses as maximum input frequency of 10MHz. narrow as 10 nanoseconds, and This 100 K ohm probe is an monitors pulse trains to over 50 MHz. inexpensive workhorse for any shop, Giving you the essential capabilities lab or field service tool kit.It detects of a high -quality memory scope high-speed pulse trains or one-shot at 1/1000th the cost. events and stores pulse or level LP -3 captures one shot or low - transistions, replacing separate rep -events all -but -impossible to level detectors, pulse detect any other way. detectors, pulse stretchers All without the weight, bulk, and pulse memory devices. inconvenience and power All for less than the price of a DVM consumption of conventional methods. £31.00* £49.00* LP -2 Logic Probe The New Pulser DP -1 The LP -2 performs the same The Digital Pulser: another basic functions as the LP -1, new idea from C.S.C. The but, for slower -speed circuits DP -1 registers the polarity of and without pulse memory any pin, pad or component capability. Handling a and then, when you touch minimum pulse width of 300 the 'PULSE' button, delivers nanoseconds, this 300 K ohm a single no -bounce pulse to probe is the economical way swing the logicstate the to test circuits up to 1.5 MHz. other way. Or if you hold the It detects pulse trains or button down for more than a single -shot events in TTL, DTL, second, the DP -1 shoots out HTL and CMOS circuits, pulse after pulse at 1000 Hz replacing separate pulse detectors, The single LED blinks for each single pulse stretchers and mode state pulse, or glows during a pulse train. analysers. If your circuit is a very fast one, you (Available in kit form LPK-1 V 1-92) can open the clock line and take it * through its function step by step, at £1 8.00 single pulserateorat100 per The logic probes shown are all suitable for TTL, second.Clever!Andatavery DTL, HTL and CMOS circuits. reasonable price. price excluding P &P and 15% VAT £51 .00* CONTINENTAL SPECIALTIES CORPORATION r111M - MN Mi I1= C.S.C. (UK) Ltd., Dept. 911, Unit 1, Shire Hill Industrial Estate, Saffron Walden, Essex CB11 3AQ. I Pnces include P &P and 15% VAT Only LP 1 £37 38 Only LP.2 £22.14 ri.)nLYLP -3 £5808 1 Only' 1 DP.1£80 LPK 1£14.88 I Only I Name Address C.S.C. (UK) Limited, Dept. 911 I enclose Cheque/P.O. for £ or debit my Barclaycard/Access/I Unit 1, Shire Hill Industrial Estate, American Express card no. exp. date Saffron Walden, Essex CB11 3AQ. I FOR IMMEDIATE ACTION- The C.S.C. 24 hour, 5 day a week service. For FREE I Telephone: Saffron Walden (0799) 21682 Telephone (0799) 21682 and give us your Barclaycard, Access, American Express ' Icatalogue Lumberand your order wii! be in the post immediately. tick box CJ Telex: 817477 MIN II= MI =I MN pm NEN oNN Noi ETI JULY 1980 65 A. Marshall (London) Ltd., Kingsgate House, Kingsgate Place, London NW6 4TA marshailt Industrial Sales: 01.328 1009 Mail Order: 01-624 8582 Also retail shops. 325 Edgware Road, London W2 40 Cricklewood Broadway, London NW2 85 West Regent St. Glasgow 1084 Stokes Croft Bristol. CAPACITORS: BOXES & CASES TTL see catalogue for full rangeSOLDERING EQUIPMENT Mullard Ceramic 63v range See catalogue for full range. 5074005 £014 5074914N £0 54 IRONS-ANTEX 1pF to 10,000pF E 24 range 5074015 CO 14 5574920 £0 31 Aluminium boxes 13 sizes. SN74020 £0 14 5074935 £031 15 watt C15£3.95 all at £0.06 each 5074030 CO 14 SN7494N Rexine Covered boxes 7 sizes. SN 74040 CO 14 507495N £055 15 watt CCN £4.20 Siemens Ceramic 63v 837448/9 5517405N £015 SN7496N £034 NEW RANGE TMEC CASES 5574060 CO 34 SN7497N E1.80 17 watt CX17 £4.20 .01: .022: .033: .047mF @ £0.06 Send S.A.E. for details & types SSNN708N 5N57744110075N E01 25 watt X25 £0.216 5.210 £4.20 .068: .1mF @ £0.08: .22mF @ Price range. £14.04 to £17.00 5074095 £016 SN74118N £076 Stand £1.50 SN7410 C0.15 S0741190 E1.20 £0.11 ABS PLASTIC BOXES S1974110 £0.15 60741210 £025 CSF High Voltage Ceramic Discs 507412N E0.20 $0741220 C0.48 DESOLDERING TOOL 3"x 21/." x 1," 56 14140 00.47 5074123N £0 42 Prices £0.07 to £0.18 Range 55174140 C0.47 SN74124N CO 53 Solder £6.50 .4110011501. 3 Prices as SN7416N CO 22 334" x 23/4" x 1g SN74125N £0.40 100pF to 10.000pF SN7417N CO22 SN74141N 00 50 catalogue 5074206 C015 50741450 0064 Voltage range up to 6Kv. 41A" x 3Y4" x 11/2" S074230 £0 18 5074148N El 05 SINCLAIR INSTRUMENTS 5674250 £0 19 50741505 CO 79 See catalogue for details. 8"x 43/." x 3" 6 £0 19 SN74151N Digital Multimeter Comprehensive range Siemens SN74215 Ell 19 SN74153N Loss PDM35 £ 34.50 BAZELLI INSTRUMENT CASES SN7430N C015 SN74154N 00 90 " Layer Polyester Caps: .001 to 5 sizes. 5574370 C0 17 50741550 £0 60 "DM235 £ 52.50 0074370 £0 21 SN74157N E059 3.3mF 5574380 £021 $57416040 E070 ''DM350 £ 72.50 Miscellaneous hardware S5744051 CO 15 557416145 £070 ir Prices £0.07 to £0.63. S07441AN £052 557416240 E070 "DM450 £ 99.00 including $074420 £0 40 507416340 £0 70 Digital Frequency Meter See catalogue for details. $074450 00 66 SN74164N £0 80 Large range of Mullard/Siemens Vero Board: Superstrips: SN7446AN 00 08 55741655 £0 80 PFM200 £ 49.80 Vero Breadboard. 50744740 £0 48 55741675 El 20 Electrolytic Axial/Radial 5N744135 CO 45 $0741745 fl) 80 Low Power Oscilloscope Vero boxes (see catalogue for 5574505 CO 15 50741 750 E0.63 Capacitance values 1.0mF to 0504515 £0.15 S074170 E0 74 SC110 £139.00 5N74530 full range) . 00 15 SN741776N C073 10,000mF 51974545 £015 50741805 £0 70 Voltage ranges 25v: 40v: 63v: SN74605 £0 15 SN74181N £1 65 CRIMSON ELEKTRIK HI Ft 5074700 £0.26 50741820 C083 MODULES 100V: 0074720 £0 24 SN74184N C1 29 507473N 00 25 5N74185AN El 10 CE608 Power Amp £18.26 Prices and types as catalogue S574745 £0 25 SN74186N £1.35 SN7475N Ell 31 507418840 E184 CE1004 - - £21.30 Also Mullard C280; Siemens 507476N CO 26 55174189N E2 26 SN 74805 00 39 SN74190N CO 74 CE1008 " " £23.91 832231/4 and 632110. All pricesCard Frames: Fliptop boxes: SN7481N 00.71 50741910 £079 SN 74820 E0.65 $0741920 E0 79 CE1704 " " £30.43 net + VAT and postage/packagingetc etc. SN /483N £13.60 S0741930 C079 5574840 C095 50 741965 E0 74 CE1708 " " £30.43 TOOLS BAHCO ....- 5674856 C070 SN7419)N C074 CPS1 Power Unit£16.96 .. 5074866 Co.25 1980 CATALOGUE -- $0741980 01 09 Side Cutter with Bezel. 05748919 E1.66 S0741995 El 09 CPS3 " £20.43 U.K.: 65p post paid AACS\ - \ Cl\'S S0749040 CO 33 CPS6 " Side Cutter without Bezel.'''',/,- Europe 85p post paid Lam. £26.09 End Cutter without Bezel. Rest of World £1.25 -:A KNOBS & SWITCHES CPR1 Pre Amp £29.57 post paid Big selection as catalogue CPR1S Pre Amp £38.70 Vero Metal Shears. ... Also Resistors; Presets; Pots; All prices + VAT + postage/ Other items as catalogue. \._ Mail order: 01-624 8582 Opto; Semiconductors etc. packaging BF 200 29p OPTO TRIACS 7415124 15p TRANSISTORS 6F336 33p Lads with internal 7415132 89p BRIDGES 40128 15p BFX30 32p 1 25 Red 10p 7415139 79p BFX86 trigger duos AC187K 30p 26p 125 Orange 10p 4A 400V 54p 66p 7415151 89p BFX88 22p AC18BK 30p 125 Yellow 10p 44 6000 60p 75p 7415155 91p BFY50 13p ACY 1 7 90p 2 Red 10p 6A 4006 600 75p 7415156 89p 50V 100V 200V 400V 600V 40149 55p BFY 51 13p 2 Green 10p 64 6000 66p iiiLLS157 69p 2A 45p 52p 60p 75p 100p 8F564 90p AF12 7 35p 28p 2 Clear 10p 84 4000 66p 90p 5165 69p 4A 52p 60p 68p 82p 105p BFY90 A5217 120p 56p 84 600V 72p 74LS168 139p 6A 60p 68p 75p 90p 112p 65019 9Sp AU1 13 150p 80p 10A 400V 72p 95p 7415174 99p BC107 BSY 954 16p 10A 600V 849 1009 7486 25p 7p BU204 149p DISPLAYS BC108 7p 154 400V 108p 120p 7491 63p 4072 17p 50208 150p BC1084 7p 154 600V 126p 138p 7492 35p DIL SOCKETS CMOS 4073 17p 0C29 89p 110p BC108C 7p 7493 28p 4075 19p BC136 0C43 50p 160p 7494 63p 8 pin 10p 4000 14p 4076 75p 15p 25696 BC140 28p 15p 160p /495 63p 14 pun 12p 4001 14p 4077 35p 20930 20p 4002 BC141 30p 160p 7470 30p 74100 110p 16 pin 13p 14p 4081 19p 201132 19p 160p TTL 7472 25p 74107 30p 20 pin 25p 4006 69p 4082 17p 8C142 25p 251304 80.143 28p 40p 7474 20p 74121 25p 24 pun 30p 4007 16p 4160 105p 251613 12p 9p 4008 6C147 6p 7475 27p 74122 36p 40 pm 40p 79p 4161 105p 251 71 1 15p 9p 7480 40p 74123 44p 4009 36p 4162 105p BC14713 6p 25217 9p BC149 20p 7482 60 74145 72p 4010 36p 4163 105p 7p REGULATORS 9p BC149C 2522194 20p 41500 1p 74154 80p 4011 19p 4402 36p 7p 2N2221 10p 80159 9p 18p 741501 11p 741 57 60p MEMORIES 4012 16p 4404 110p 252368 15p 14p 741502 12p74161 85p 4014 59p 4412 86p 60160 35p 30p 13C1674 10p 202369 14p 741503 12p 74175 63p 4015 73p 4445 174p 7028944 20p 7805 57p 30p 741504 12p74180 21102 109p 4016 42p BC178 12p 84p 211 400p 4446 148p 202904 15p 7812 57p 17p 741510 19p 74181 151p 4017 79p 4502 BC1 79 12p 7815 57p 4027 275p 99p 257904A 15p 17p 741511 20p 74191 80p 4018 79p 4511 89p BC182 8p 252905 7818 57p 12p 4116 7500p FIC1821. 15p 74520 18p74192 80p 4019 45p 4512 89p 9p 252906 7874 57p 17p BC183 9p 15p 741530 18p 74193 80p 4020 89p 4514 229p 2029265 7905 140p 25p 4021 801831 9p 10p 741537 24p 74194 80p 83p 4515 229p 7029260 7912 140p 45p 4022 BC1841 9p 10p 741542 89p 7415175 99p EPROMS 79p 4516 99p 7529260 10p 7915 140p 25p 741551 24p 7415190 110p 4023 16p 4520 BC186 20p 53447 7918 140p 25p 70p 80217 9p 102p 74L555 28p 7415192 115p 2708 750p 4024 49p 4522 129p N3702 7924 140p 14p 4025 BC2121 9p 13p 741574 39p 7415194 115p 2716 2600p 17p 4526 125p N37(74 LM 32075 149p 28p 4026 BC21313 Op 8p 741575 46p7415195 115p 129p 4531 125p N3705 8p LM320T8 149p 14p 741576 39p 7415196 95p 4027 39p 4555 92p BC32 7 13p 1.M320115 149p 22p 6C376 13p 037019 8p 741585 99p 7415197 125p 4028 59p 4556 69p N31(195 LM320718 149p 26p 4029 BC337 16p Bp 741590 36p 7415257 99p CPUs 89p 4581 269p N3866 35p LM34015 74p 48p 74LS93 79p 7415260 99p 4030 49p 4582 115p BC338 lip LM34078 74p 50p 8C440 32p 6.C1006 10p 741.5114 49p / 415273 199p Mk 3880 1250p 4034 189p 4584 59p LM340115 74p 15p 4035 00547 9p 12p 741,5122 65p 1415367 59p Mir 3881 750p 99p 4585 99p iM340718 74p 15p 4042 BC548 9p 60p 74LS12 3 65p 73LS3 771 159p M131382 750p 69p 4043 W Isostock BC5170 14p 86p DIODES 4044 83p Nscom 1and 2 00558 12p Sharp 4046 109p TRS 80. 5 7i , 99p .1,a 1 1rr 10p MEMORIES EPROMS CPUs OPTO 4049 RUBOR, PET Con, BO 14 45p 99p 8,711,1 Op 4050 pukit and associated 80 3'7 229p 63p software and firm, 8411r7 9p 4051 69p BC 7r,17 16p 104001 4p 4052 wareAllow 28 days RC, r0 12p INTERFACE COMPONENTS LIMITED, 69p for Postal Delivery 154011, 4p 4053 69p RC, i 1 12p IN4002 5p 4066 49p _0071 12p OAKFIELD CO, ROAD,AMERSHAM, BUCKS HP6 6SU 35p P&P /0300, 5p 4069 17p Hf 1 1, 25p ,61145 5p TELEPHONEMORE:02403 22307. TELEX:83788 4070 17p VAT pi1 8, 25p 3p 4071 17p Write,telephone or call. Access or Barclaycard accepted additional 66 ETI JULY 1980 I VEROBDARD TERMS. VAT. CWO. Cheques etc melee to Greenhask Electronics awl QUARTZ I LI" Pilch earthcopper\ Add VAT to Ill prices at 15'. except where staled otherwise. Pest etc: UK 35p strips Greenbank 51 (+5p VAT = 400) per order. Export: NO VAT hut add 35p (Fare). 75p (Europe) led 'BARCLAYCARD' text" Mack of 14p Greenbank Electronics 32.76901a E2.50 elsewhere. Access. Barclaycard. Vise. telephoned orders accepted. 25" x3tk" 53p (Dept TlE) 92 New Chester Road, New Ferry 97=7 rlietchl C3.23 62p wiversihu. port depts. etc can telephone their orders (or immediatee- 4 2'4x5" Wirral, Merseyside L62 54G 60 Kit 0.95 text/. 11.86 (Tel 051-645 3391) dispatch oe accasot) 100.0 KW £3.02 x34.." 62p 200.0 155 0.92 Me x5" 699 These cut prices*, Amateur Users end Export. Note:Industrie1 users - quantity 204.1 KM 012 Pi" ir E2.40 CMOSI pokes .e000 Me. Mostly Motorola, RCA 252144 KR/ 012 4.7neit.r £3.14 3072 KIff 0.92 CI" Plaeriboard UV EPROM ERASERS 1096 95p 4451 E3.81 4519 5.38 4042 809 4030 18p El 415 312.5 KHz 0.12 (no steps) 4343 904 4097 E3.40 446 1 0.3.43 4552 4001 25p 455.0 Kitt 0.95 38p 4098 0120 4462 £4.41 453 6150 8 x2 4002 25p 4044 90P MO 191z 0.62 59p 4099 E2.00 4490M E4.20 454 El .38 37," ir 5" 4006 95p 4045 £1.45 008 MHz 0.92 449099 E3.14 4555 78p 37,11x 1181 01.56 4007 18p 4046 E1.10 413100 E2.20 E3.92 280 Mb Tammal pets El 50 500 4047 El DO 40101 0152 4500 16.95 4556 72p 4608 80p 0432 MHz 0.62 01.17 0102 E1.80 4501 asp 4557 E3.86 4-0 MP hoard 4009 40p 4040 55p .10 MHz 1312 0103 01.80 4502 E1213 4558 E1.25 MP Inailloaril E2.91 4010 50p 4049 45p 091152 Mg 0.23 70p 4559 04.38 Mel 104 nine/ 93p 4050 49p C104 99p 4503 4011 25p .4576 MHz 13.62 £1.29 43105 99p 4505 05.71 4560 02.50 Pi %Khoo tool 4012 18p 4051 80p .500 Mk £3.02 40106 90p 4506 509 451 81p 4013 50p 4052 00p 56250 Mt 012 SOLDERCON PINS 80p 40107 60p 4.507 55p 4562 05.60 4014 Up 4053 .000 Itilz 012 10050p 1001E3.95 C101 14.70 4508 E2.90 4566 El 59 4015 84p 4051 01.50 .2768 MHz 13.23 40109 El .00 4510 999 4568 E2.38 4016 45p 4055 E1.25 .579545 MHz 11.95 IML SOCKETS 40110 £3.00 4511 £1.50 4569 E2.50 1017 110p 4056 01.35 93216 14111 £3.92 814/16 pie 40114 £2.50 4512 804 4572 40p 4018 09p 4059 E5.00 000 Wet E2.90 10p/12p/13p Two easy to use unitsdesignedforboth 03.39 4514 £2.65 4580 5.77 4019 45p 4060 E1.15 161 032 MHz E3.23 18,2922 pie the professional and amateur UV -prom user. 40182 E1.40 4515 £3.00 4581 E292 4820 99p 43627 010.00 096 MHz E3.23 111p/ 209/ 259 40192 E1.40 4516 01 10 4582 0104 Features. 4021 El . 10 4063 E1.20 194304 MU E3.23 2498/413 pie 40143 El 40 4517 £446 4..583 90p Can erase up to 14 proms 4022 E1.00 4066 55p 433619 MHz 11.25 30p /40p/50p 40194 E1.18 4518 t1.00 4584 904 4023 27p 4067 (4.50 .608 Mg £3.23 24 pa reale& lever tapeler Special short wave ultraviolet tube. 10251 E1.411 4519 80p 4585 E1.27 4424 sop 4%8 27p 800 MHz 0.23 s amino hate 0.50 Erase tirne variable between 5 and 50 minutes in 5 minute steps 989 4520 E1.00 4597 E2.44 4025 27p 4069 27p ON 915 MHz 13.23 4521 £2.50 4598 £2.90 TIMER 1C3 (preventing pver exposure which may shorten prom life). 4026 E1.30 4072 30p 4161 912p 000 MHz 13.23 98p 4522 El .1 1 4599 £6.95 1E555/556 29p/49p Sliding tray carries proms on conductive foam. 4027 50p 41371 25p 4162 .065 081 E3.23 25p 4163 98p 4526 01.08 4700 El .75 Safety interlock switch prevents the timing circuit from operating 4018 Up 4012 120 MHz 0.23 1521 E1.50 OP -AMPS 4029 99p 4073 25p 4171 90p 185 MHz 0.23 and switching on the tube with the tray open. E1.20 IAN MVO dips) 4075 25p 4175 01.15 4526 13.23 4030 55p 000 MHz 64p -Mains on" and "Tube On" indicators. 4164 01.16 4529 £1.30 CA 3101E 4031 E2.00 4076 E1.07 144 1411, 13.23 4408 E9.37 4530 70p G 3140E 35p Smart textured caw. 4032 11.31 4077 29p 400 MN 0.23 4531 £1.45 91 741 [Texas' 22p Complete instructions supplied. 033 0.80 4078 29p 4409 E9.37 55360 MHz 0.23 4110 18.554411 4532 E1.30 4034 E2.00 4061 27p 000 IAN £3.23 Supplied complete with mains plug and flex. E5.60 4 DIGIT LED DISPLAY 035 ELIO 1082 27p E10.72 4534 168 Mg 0.23 4412W 114.93 4536 E3.69 csense Model UV141. Price £77.70 6136 ELM 40135 74p 680 MHz 0.23 44159 E5.24 45371 E26.10 oasts snits entity 4037 11.15 4086 72p .86432 MN 0.23 4538 £1.20 420 351 10.31 E4.25 Also available without timer as 400 11.20 4089 E I .313 4422 E5.66 .000 heir 13.23 4539 97p 039 12.95 4093 80p 4433 E12.30 388600 MHz £3.23 E2.50 41354 E5.40 4541 11.19 Model UV140: Price £61.20 4040 11.00 4094 967237 CP £3.23 LED DISPLAYS 43.81 4543 01.80 041 809 4095 95p 4450 375 Wiz 13.92 M. 701f 99p PROM WASHING SERVICE 50p each prom .800 14117 1312 IL 727E/728E 12.011 74C904 85p 740926 0.26 74C76 814 741163 0.72 opal MHz 13.23 01. 747E/750E I .80 740927 E7.26 740 7463 E1.94 74064 0.62 74C9115 01989 0.245 Mg 13.23 90 5%/560 E1.29 740928 17.26 74185 E1.94 741165 01 .62 141906 85p 0.700 Mit 13.23 85p 141929 07.90 COMPUTER BOARDS 74C00 339 741M 96p 74173 01.35 740907 0.92 MHz 0.92 85p moo CRYSTAL The followings an extrect from our leaflet ref 'M P4' which i vailable 74102 33p 74189 16.57 74174 £2.27 74C908 0.44 80195 1.000 MP 0.92 8X96 92p DISMAY free on request (a 9" x 6" SAE helps, but is not essential). See 74101 33p 74190 11.28 741175 11.27 740909 02.45 2.000 Mb 0.92 85p 4005" Dgils 40 pin OIL Microprocessor section to the right for board pee.. 74108 33p 7493 11.28 741192 E2.59 740910 00.17 81X91 4.0 IAN 0.92 92p 19.95 For many people the wide choice of micro -processors now available presents a 74/10 33p 74195 11.56 741193 0.72 711611 00.69 90C98 4311118 010 0.23 8516 16.20 difficult choiceTo understand any particular microprocessor in depth a 74114 E2.12 741101 11.83 7411M 012 700912 EID.69 9000 MN £3.02 86C2988130 12.90 development system is almost essential however in the past to understand 7420 42p 741150 E5.72 741210 110.17 740914 £2.12 8.000 MHz 0.23 CLOCK CHIPS 12.90 more than one several separate development systems have had to be 14130 42p 741151 0.06 74022174073 E2.17 74C915 EI.72 432 MN 0.23 4651224A 02.60 El .59 purchased 70032 42p 740154 15.72 E2.69 740916 20 000 MN 0.62 MK 50253 15.50 741921 07 07 The reason that separate systems, one for each processor. have been necessary 7C42 (1.30 74057 13.30 741374 12.69 29 1134 MHz £3.23 1411 91366 £0.50 is due to the fact that indivtdual microprocessors have their own individual 74148 (2.07 740160 11.72 74901 05p 740922 5.49 27 0 MHz 0.92 features in one case to access memory a separate read strobe and write strobe 14173 Slp 74CI6I 11.72 74902 1159 711923 5.60 27.648 MHz 0.92 SIX DECADE is required. in another a 'read/write' line is used in combination with a 74174 72p 740162 £1.72 740903 85p 14/925 £7.26 396666 14117 0.23 COUNTERS combined strobe called 'valid mernory address and phi -T With some 48.000 IAN 0.23 111( 50395'6'7 09.90 processors. the same address bus can be used for both memory and 100 000 Mt 13.23 MODULATORS, PM 503913 9 E7 50 'input/output ports', under the control of a mem or y. request or an SWITCH 116.000 MHz 0.23 'input/output request' control line. Naturally, If a development system takes advantage of any of the particular 15111 E36 11HE CI 36 MODE PSUs Osten libeelstor 12.50 unique features of this makes it more difficult to AC 52215 NAM 100.00AC DATA UM1231 UHF 11.36 Wee Mote in Oils section all dale books graft some other unrelated microprocessor onto the same bus at a later date. 92215 N/61. 1211/111. -129/14. - 1149114er tale seiesims are subject to 0". 941. For postage A Untversal Micro System provides a basic PUS structure on which any one 51,/11 IA £00.00 pr peeplers etc] E4.70 see 'Terms- se top of page. mcro-processor can be connected. The system uses a CPU (Central Processor AC 5421$ Wad 011.20 Unit) card which is separate from the rest of the system. and this allows the 11141263 EM Seed SE AC 9425 511104. 124/24.-15/24. - arras Wiley 12.50 same memory and interfaces to be retained when a different MPU is used. 54/0.16 0125.50 113 pap Electrum Preterit Index 12.77 The basic system bus consists of data and address buses together with read and Morth Trestle Libraries' EI.50 (VDU) in the write strobes By locating the data input (Keyboard) and output INTERFACE 0650 pep COSMOS %Whole RCM 14.95 memory space then such chips as the 8080 7280 family. whichnormally use MICROPROCESSORS 811595'6,71 El 40' c3I pp664,to SC MP Programming by input / output ports, tan now be used without any fundamental change to the moo 75491100dose 504 Or. Gerry ihmulreel 13.75 for 75p bus land as a bonus. users of these MPU s have all the ports entirely free 5030 IVO 10.55 75492 92p an pageA Guide to Meailmel E3.95 E3.45 their own purpOSeal 6/02 lift 111.10 211425 424 Fops MK Reference Gaide POPO COMPUTER BOARDS sop The range of p c b 's includes boards to implement a memory -mapped VDU. 5810 on RAM 12.97 8T26 £2.64 OM la 1116 ffilastelq cassette interface. keyboard interface. PROM programmer. and a number of 114 203 me fibreglass. 25p racoon WI 13.75 1174 48p cfi pp dab ler Mk 4118 RAM and ROM cards. All the cards are of International Sae 114 s 203 rem nth gold plated edge con- 50p 6820. 5821 HA 13.1141 MOSTEK VDU ICIARD 16.pep data ler IMS 8154 115P-84 6501 Maltoeill (4i/" x Ell except for the larger power PSU A power supply card This latter nector 509 Buhr.' SC, MP CPU E9.40 6950 ACM £3.011 148-2 E125.1M 51 -pep data ler SC. MP II [Wipe) card issued so that it can be bolted to the side of a standard 4" chassis module 5100 gage COP 1802 CPU User Mem% (RCA) 04 50 56817 Proloboerd E9.40 /USN E2.64 CRT Controlet Urals which is then compatible with the other cards The cards have a standard c45 pop fine PeBleary ariteweic Rostiset for 110 1% card E9.40 0502 Rumpus 151 SF 196311611 1.50 43 -way edge connector, with one position used for polarisation. At 51013 11MT 111 1602E4.00 105041 04.50 ter of bus connexions VDU 'A sal 03.90 6502 £12.00 We do not propose to defend the (relatively) small E6.22 41.51013A 14.70 431 pegs Fecal Peel Wheelie Regimes for NW9 at E8.90 6520 HA (42). against such standards as the '5100 " bus The S-100 bus. AT3-1014A 15.80 CO MM pi .141340 E4.50 V% -B' Mee E9.40 ire expensive. In the as it originated in America. is bigger +- CMOS 41.3-1015 15.00 c43 pee 105080 MPU Product Gybe MCA] 75p EPROM Progremser 19.85 same way, a Ford 'Granada' - x40Cortina', but it COMM COP 180211 515 pap COP 1002 lestruclan Summery 25p (2M801 E940 COMM COP 181321 E10.85 CHAR. GEN. KEYBOARD doesn r mean a Conine ova - it may even 070 LAIdarsint..MOS 91611 E1.50 40 PROM board 15204s1 ENCODER OA COP 1861 0.25 259 be better value, KM 66780 I pop COSMOS Pecker Seethes laid. 11141 d 3U 1a9" rack 09.40 19.75 75p The Int,- ASSts oat,v11:4,°°.,;::' STATICS [Mostly 450.5) PM 2302 115.29 021 pap COSMOS Digital Integrated Circuits 11191 Akt% 80 PROM hoerd 12708s) "larnZitiyh E9.40 2101-256 12.25 10-3 2513 (Se Uppercase' 16.00 etc.vat ck '3' ' tt -,citlet the firm R SrS Dr RAM board 12107,1Ilt- 2102-10Cl 11.20 DM 8678 CARAVIS 014.27 14.V.coto(cst a ,:tet l':'tvs. 21. E9.40 2111-256 4 E1.95 AT 5-2376 09.75 (14.95 co s6...0_6',17eIsompes, M MM Herd 12114.1 19 2112-256i 4 (2.25 REVISED ZOODATA PACK xeisotsevs3 110111MARE TM coffees ofthis dale pack have changed.II now % 19.40 014/4045-18 4 04.39 e purchaser 2K Tay Base tar 180 includes dena booed roloies and also corers some 2.030 . O. eye `00.. TAPE interfere . 18.90 21141-1K 4 (5.50 °te _,..t, ,1 assembly 27081 125 Sher alumna ::::: s as well. Regreltebly the books vst1 _I, , s A,It. _, jo, 0 Keyboard InterfereE8.90 4118-10 120.99 iM At 00.77PRVF 4K RIC. le 4 2708 155 caul he upheld ...... tely awe are !ores' to Puy y st. a 0 ,oe. ctot. 0000- os P211 5v 12r. -12v iitte cotes c eplf - vtrtually 111111 lel in 41 2708 E55 the packs "epee. Coffees Der sow( E8.90 DYNAMICS we ERBUG 1+2 2108 119.95 c275 -page 280 Programme Manuel 663'lgoescrOte esPSO 1 PSU S. -IN ward 05.50 MK 4116 1811 250.5 04 95 The i eI51(06 tnt You KITING II 27081 114.95 c525 -page Marmompter Component Deli PM Sr AIK 4811 211 8 130.52 's ,,twill be Further death on request 61.611612 a 27081 134.90 55 -page 180 Micro Reference Mamie [pocket stre1 chuc's dook/te.de-t'o ttt,e c 31 ' 00.03.1.a. or 61113110 M11 11it 21381 119.95 c130 -page flarpospear Systems Dela Book e -- tot,fto ZOO UV ERASMILES indeed ,,s63.i.,e6...e.,. ,.' C ts not St: MP Iffellas 283 05 12 (1% 2708 IK a 1 0975 permit y ,,,eC,...oseSt".,1 0°_.e, (Os_ voseg. ,eouln, 11 27081 119.00 1110-170 (2 -MN) 15.05 2716/2516 208 amble 5r offer guy ...- w ..0 vitt, needs see e- .,stose,3 ca t4 Pow 710-P10 (2,,wetzl CIAO 017.95 VOLTAGE 2532 x8151 c50-pege Finite State Faunas [Cartoons pulling he IAN El le the 49147 memo te E47 00 REGULATORS 50MWASHMG each Free programmiag on bean level) %Hee Press' £2.00 _s any of theeXtit3 chops 1 7805 15p design of OA 50ga H-300 +VAT) C--11te. eltet 1905 El MS arrangemen 00 _dote' _tos `tee°ie c175 pep Home Campers Registers Glossary md SC/NP II RAM I/O 97p %Net% ed. (IV PROM ERASER 7812 14.95 obsolete ovei _oes16 5C/MP141541 GSM Guide by M ler ,18Sap 10111111fium1 have been pro deg' , .610'0,1' 01 10140 E61.20 7912 E1.00 MS 8154 RAM (/0 0.18 LM 323K E5.61 pattern which , 'ied espSVI ss 's0 UY141 177.70 Kb\ - Often these cat tp,4 V 7415283 11.92 ,41.5375 £1.60 0°,:(70 74527 2139 741576 404 741515 600 7413163 E1.10 7455240 62.311 ing An.,ti9° e oet /413293 ct.se 765377 12.12 1' w A. tits ..0 74LS I 741.511 alp 741278 30p 7415126 60p 7413164 11.14 740241 0.32 regulatoror gat, 745293 11.28 7445318 11114 . already /41500 14p 7415M 22p 741053 01.15 7413132 95p 7455155 75p 740242 12.12 Input, Output Re. iSee't. D'.,Alfi'le 7415295 11.55 7415379 12.15 eel 741501 14p 76332 27p 741%5 E1.14 7415116 559 1413165 5.29 74/5243 0.32 :rear, v:o thisur facilityi,r.v- 7415298 11.68 7415384 86p .010 faint clean away at 14102 16p 741533 39p 741586 439 1443138 85p 7115170 E2.118 7413244 11.70 7415324 12.40 1415386 86p -.tog extra Integrated circuits 74/503 16p 74/07 39p 741SSO 609 740139 85p 7415173 01.05 7415245 7.3.50 the thought of cutei v04E' 7415325 12.90 741090 1233 .0. but itis not for these people that 76504 16p 741538 39p 741591 0.04899 7415145 El DI 745174 E1.06 1445247 11.00 and bus of wire in thi so00 7415326 12.94 7415393 12.30 We would like to think of this system as 741505 20p 741540 28p 74542 7443147 11.71 745175 0.10 1415248 01.90E1.90 this sort of system has /415327 12.86 7415395 12.18 your own personal design. perhaps as en 74/508 25 741542 989 11593 89p 74/5148 11.73 7415181 E3.98 701249 basis on which you c 7415377 11.48 1415396 1215 74/S09 22p 141.341 90p 741595 11.16 74/3151 969 7415103 62.98 7415251 11.34 alternative to the use of Veroboard or etching your own pcb 7415348 11.86 7413398 12.76 (Further sections give an outline of each card in turn Although we have in mind 741510 20p 74/548 11.20 74,596 11.16 701153 76p 7415190 (1 .40 765253 11.42 7415352 12.28 7415399 12.30 74/511 22p 74/540 11.20 74597 44p 7415154 11.70 7415191 01.40 7445257 11.18 all sorts of erotic future developments fe g high resolution graphics floppy 7445353 E228 745445 1150 741512 234 79551 24p 7115109 559 7415155 96p 7450192 ELIO 1415544 11.46 disc controllers. dynamic highdensity RAM cards. programmable VDU 740365 65p 7415447 11.44 141513 38p 141554 210 7455112 55p 740156 96p 7415193 £1.30 7110259 11.16 formats colour displays. Light pens. sound generators etc I we prefer to keep 14/3385 65p 1934% CUM 741214 754 741555 30p 1415113 50p 763151 76p 7415194 E1.66 741551 54.50 quiet about them until they actually exist All of the cards described actually 7413367 65p 7455668 1112 141515 304 741163 11.50 7415114 509 7443158 96p 7415195 01.36 7415266 52p exist. and at the time of writing (September I 9791 most are in stock (We plan 1415368 66p 1415669 11.82 741520 20p 741573 46p 7415122 70p 740160 11.28 7415196 El.% 7415273 0.44 tt so they are all in stock but people will insist on buying them without caring 7415373 El 80 7415670 12.48 741521 22p 74574 4Ip 1415123 70p 7413161 909 7415197 £1 .40 7415275 12.50 what havoc they wreak 'n Our stock controlill 1412374 E1.95 74524 48p 741315 asp 14/5124 11.00 7415162 El 38 74/S221 96p 7415219 66p ETI JULY 1980 67 STEREO IMAGE CO-ORDINATOR caz decay speed rill left right oils justaHl 0 AUTOMATIC TRIGGER INTERNAL - MANUAL EXTERNAL] Following his article on the 1537A VAC, Keith Brindley comes up with a complete application using this most resourceful chip. perhaps an explanation is required! What, you may ask, is the musician to concentrate on the music rather than the a StereoImage Co-ordinator? Brieflyit'sa panning equipment. control - simple? - well, not so simple. Panning is an Control over the stereo image is provided by four meth- effect whereby you apply a single mono sound source and ods: derive two independent adaptations of that original sound, Manual - asingle pot positions the image wherever which together form the inputs to a stereo (or 2 x mono) required. amplifier. By varying the amplitude of these two adaptations, Sweep - the image is swept from one channel to the the stereo image they produce can be altered providing an other at a variable rate, automatically. apparently moving sound source.Itis an effect used quite Automatic Trigger - the instant a note is played or sung often in recording studios usually with modern rock and pop the image is swept from one side to the other at a completely music. Commercial units are now available (though not as variable rate. effective or as good as the ETI Stereo Image Co-ordinator), External - control is accorded by an externally applied which produce the effect live, for stage work, but in the past voltage eg from a foot pedal. panning has been predominantly a studio technique. The unit utilises the 1537A Voltage Controlled Atten- uator which as ETI readers will know is the high quality Not Only But Also (good enough for studio applications), recently introduced, integrated circuit for VCA use. All other active components The ETI Stereo Image Co-ordinator produces the usual used in the audio section of the circuit are high quality, low effect of panning using a manually turned pot, but added to noise types which coupled with the considerations of careful this are the exclusive facilities of automatic control over the PCB design should allow the builder to construct a device image produced. The use of these facilities obviously allows which is at home in the studio as well as in live stage work. 68 ETI JULY 1980 PROJECT This box of tricks gives you the opportunity to try out what has up to now been an effect used predominantly in the studio. The stereo sound image can be controlled automatically or manually. You can position the image in one place and keep it there or continually sweep the image between channels and more. Any input signal within the range 10 mV to 10 V AC possibility of pickup in the audio section. Any jumpers or should successfully operate the device, although obviously the wires only carry DC control voltages or power and are, there- best signal to noise ratios will be obtained with the larger fore, of no problem. There is one exception, however, and that values of input signal. is the connection between the Auto Trig output on the right The overallsignalgain of the Image Co-ordinatoris hand board and the Auto Trig input on the left hand board. approximately 6 dB, which allows for a unity gain output This should be screened lead taken neatly, either under or over signal when the level pot is at approximately three-quarters the boards, keeping it away from the PSU section. of its rotation. The right hand board is double sided whilst that of the left handis single sided with jump leads. Neither are too Construction difficult to construct, although it is worthwhile when building The project consists of two printed circuit boards which up the project to construct each stage separately, testing as together hold all components, switches, pots, etc apart from you go along eg start with the PSU then the automatic trigger, the nine LEDs. This makes construction a proverbial "doddle" then the sweep, etc, etc. In this way any faults which develop and ensures high standards and a good chance of first time can be traced to one particular area very quickly. Actually this success. constructional methodishighly recommendable with any Roughly speaking,therighthand board includesall project! Test procedures are described in the section on Set- components to the right hand side of the circuit diagram and ting Up. similarly the left hand board includes all left side components. IC sockets are advisable though not necessary, likewise The left hand board also contains the PSU. cermetpresets,although more expensive,presenteasier PCB mounting pots and switches are used throughout setting up and a high quality than their cheaper carbon col- eliminating the use of flying leads, therefore cutting down the leagues. MAINS OUT $N The simple layout of the rear panel -- mains in, signal in, signal out. ETI JULY 1980 69 HOW IT WORKS 0 The main function of the unit is to create an impression of a CI V2 6AW-rar- stereo image from a single signal from a musical instrument. This eMe 6M6 A01? TTR 1M3 1M2 22. is done by feeding the signalvia IC4 (a quad op -amp) to 2 SUSTAI RI 22k parallelled VCAs whose output amplitudes are controlled by an RVI lkO C3 67k 15008 RV3 SENS external control voltage. These VCAs form the output channels !CIA 14 I 02 W1 ATTACK and are buffered by IC8a and b, providing drive for a stereo Ca 3 power amplifier. The stereo image is created simply by allowing 9 the signal output from one channel to be greater than that from Ca 100n RVi + the other channel. The origin of the sound thus appears closer Cl 100k to the first side of the sound field than it does to the latter. T MCA c, Interested readers who wish to know more about the VCA chips in question should refer to the March 1980 edition of ETI cu for a detailed discussion of the 1537A VCA. 105 provides phase split control voltages of 0 to -10 volts DC and -10 to 0 volts DC from a single input voltage of 0 to +10 volts DC. RV15 provides a depth control which simply limits the effect of the control voltages applied to the VCAs. IC5a inverts the DC control whilst IC5b inverts and also offsets it so that both outputs are in the range 0 and -10 volts, al- though 180° out of phase. IC5a also is a fairly high impedance buffer so as not to load the source. SW1a gives selection of whichever source is required, there being three internal, sweep, manual and automatic trigger and one external method of controlling the stereo image. The corre- sponding LEDs are also switched in via SW1 allowing an indi- cation of which function is in use at the switch and also at the function controls - see photographs. LED 1is a special type of LED with an integral IC to provide an intermittent, flashing display. As this is in series with two other LEDs (2 and 6, 3 and 7, 4 and 8, or 5 and 9, dependent on SW1) then all three LEDs will flash on and off simultaneously. External control of image is provided so that, for example a foot pedal can be used to control positioning of the applied signal within the stereo field. RV10 adjusts for various values of pots inside the pedal, although 100k lin is the nominal value. RV12 acts as the manual pot in an identical fashion to an external control pedal pot but positioned on the front panel. The signal switches which comprise SW1 a and b might be slightly difficult to get hold of so itis worthwhile taking your PCB along with you to make sure you get the right ones. 1G Also see Buylines. Various other types are around but in our 111 LEFT° (dare we say it?) vast experience, these switches are by far the most superior for signal switches, which demand low resistance CONTROL voLTAGE contacts and low noise levels. If you use the same push -fit fvARIARLEg1=1JSTA knobs for the switches ie coloured transparent fronts you may CON like to do the same as us with the consecutive function marker ,:l'OrP:hvotr,:c`y" LEDs and glue them into position inside the switch knobs so that the flashing indication is visible through the front of the INTERNAL V° switch. The square type of LEDs now available are ideally rT.Irsg1It',?' WROvIDES CORRECT CO ROL vOLTAGE suitedfor this application. Alternatively the LEDs can be 'TTOVCASI panel mounted vertically above the switch front. If LED 1, a 0 flashing LED with integral IC, cannot be obtained an ordinary LED can be used in its place - but replace ZD1 with a suitable limiting resistor eg 560R. The control marking LEDs should be positioned close to Fig.1. Block diagram of the Stereo Image Co-ordinator. the corresponding controls in order that the user can clearly see which function is in use. Finally use PCB pins for external connections so that when the two boards are fixed in their case side by side the nine links can be soldered into position along with input and inserted next (R1-9, C1-7, ICI and 2, RV1-4 and D1-3). output connections, without removing the boards. This can be tested by applying an AC signal of about 500 mV at its input on the left hand board whilst watching the voltage across C7. (All four pots should be mid -position). This voltage Setting Up should increase from 0 V to about +12 volts then after a short time decrease back down to 0 V DC. After the PSU sectionis complete, it can be tested to The sweep generator circuit can be built up next (R10- make sure that the correct supply rails, +15 V, 0 V and -15 V 18, C8-14, IC3 and RV5-9) and tested. Set all pots and arc obtained. presets to mid -position. The DC output voltage at pin 7 of IC1 The components around the automatic trigger should be should be a low frequency near sine wave oscillation approx- 70 ETI JULY 1980 PROJECT: Stereo Image Co-ordinator 0 v 9.1 C18 j.D1r. 29 100n R30 4k7 C23 R31 100n 2 IC6 V158 0/P R32 047 10 ,-Wt --.---9 104 C20 Rla 2258 /7"7 NOTES ICI 58 ARE 11353, T1072 DUAL J FET OPAMP IC2 IS 555 v IC3 IS 8038 FUNCTION GENERATOR 100n IC4 IS L F347 ,110)4 QUAD J.FET OPAMP R4 2 IC6,7 ARE 1537/1 VCA, 3k D12,3 ARE 1N4148 70115 4V7 400m1V LED 1IS FLASHING LED LED 2-9 ARE RED LEOS ROUND OR RECT. 44 C32 07p 1C7 CB. '5-9°' C30 RIGHT 0/P 11,./k RVIE1 ROS c33 100k a4) LEVEL 10 SEE TEXT R47 Fig.2. (left) Circuit diagram. 29 2208 RV1S P-A-AAA2S. Note the orientationof DEPTH /7177 LEDs connectedtosignal 010 switch SW1. imately 10 Vpk-pk (adjusted by RV8 and varying between 0 and +10 V DC (adjusted by RV9). By altering RV6 and RV7 which control the charge and discharge rates of capacitor C9 Fig.3.(below) Power supply producing +15,0,-15 volts output. (which in turn controls the overall frequency and shape) the best setting can be found whereby RV5 controls the frequency of the sine wave between approximately 0.1 Hz and 10 Hz. Fairly careful adjustment of these two presets is necessary and it is a distinct advantage if a scope is available with a slow time base so that the waveform can be studied for purest sine wave. The manual control function circuitry is simple consisting of only two components RV11 and RV12. The DC voltage at the wiper of RV12 should vary between 0 and 10 V dependent NOTES tco IS 8915 on wiper position and is adjusted by RV11. The external control circuit is equally as simple but an external pot is necessary in the shape of a foot pedal. RV10 adjusts for a wiper voltage of 0 to 10 V DC for different values of pot. Alternatively a control voltage of 0 to 10 V DC relative to chassis can be fed in from some external control circuit. BUYLINES The control voltage phase splitter is next to be assembled and set up (R36 -40, C27 -30, IC5 and RV13,14). With a The dual and quad op amps are available from the better mail known input voltage of 0 to +10 V DC (derived best from the order companies, if you cannot obtain them from your local manual pot by pressing the manual switch and varying the pot) stockist. Electrovalue supply the printed circuit mounting pots. The signal switches were RS Components stock and these the voltage at pin 1 of IC5 should be 0 to -10 V DC the op may have to be ordered through a retail stockist. They are worth amp being a simple unity gain inverter. The output at pin the bother of obtaining. 7 should be the same size pk to pk (adjusted by RV13) but The caseis_ a West Hyde Developments type CL2CDJ. Finally the 1537A VCA chips can be obtained from Aphex 180° out of phase ie -10 to 0 V DC (adjusted by RV14). Audio Systems UK Ltd., 35 Brittania Row, London N1 8Q H. There is no further setting up to be undertaken so the rest of the circuit can be installed and testing of the whole job undertaken. ETI JULY 1980 71 Construction should pose no problems. The two PCBs hold almost all of the components and controls. IC9 C36 OV +Ve -Ve C37 R3 cn Cc C.) CC C? " I 1 't. R10 warkiitt 1 C tc 7 D2 NAT R14 IC3 1:1,11 R12 C.) R16 SENS ATTACK SPEED MAN RV1 Fek/3 Illt R1/1112 AUTO LED INT LED MAN LED MAN LED7 A AU INT LED LED 410 Fig.4. Component Overlay for the single sided hoard, which carries the power supply. 72 ETI JULY 1980 PROJECT: Stereo Image Co-ordinator TO AUTO I/P TRIGGER R39 C18 C 04+ C 2 9 AUT INT MAN EXT LED 5 LED 4 LED 3 LED 2 4 4 4 4 4 0/P RIGHT OP LEFT RV1 EXT LED6 EARTH IC a AA/ AUT INT MAN EXT Srl 1 Fig.5. Component Overlay of the double sided board. PARTS LIST RESISTORSAll 1/4W, 5% CAPACITORS R1 1k0 C1,12,17,24,27,30,3322p polystyrene R2,3 6M8 C2,5,6,8,10,11,13,14, R4,5 1 M2 18,19,20,21,23,25,28, R6,20,32,35,43,45 4k7 29,31 100n polyester R7,10,11,12,25 22k C3 1500p polystyrene R8,9 1k5 C4,9,26,34 luO 25V electrolytic R13,14,17,24,39 47k C7 10u 16V electrolytic R15 82k C15 22u 25V electrolytic R16 33k C16,22,32 47p polystyrene R18,36,37,40 100k C35 680n polycarbonate R19,20,21,31,33,44, C36,37 1000u 25V PCB electrolytic 46 10k C38,39 330n polyester R22,23,26,27,28,29, SEMICONDUCTORS 41,42 3k3 IC1,5,8 LF353, TL072 etc dual op amp R34 220 R IC2 555 RI] 68k IC3 8038 R47,48 12k IC4 LF347, TL074 etc quad op amp IC6,7 1537A PO IENTIOMETERS ZD1 5V1 zener 400mW RV1 47k log PCB mounting pot LED 1 Flashing red LED v",.1 1 MO lin PCB mounting pot LED 2-9 Red LED R V3,4,12 100k lin PCB mounting pot D1-3 1 N4148 RV5 10k lin PCB mounting pot RV6,7,9 500k min horiz cermet preset MISCELLANEOUS RV8,13 47k min horiz cermet preset SW1 a and b 4 off push button signal switches 2 pole RV10,11 100k min horiz cermet preset C/O + appropriate hardware (see text) RV14 220k min horiz cermet preset T1 15-0.15 6VA mains transformer RV15 100k lin dual PCB mounting pot FS1 500mA fuse + panel mounting holder RV16 47k log dual PCB mounting pot Mains connector, input and output sockets case (see Buylines). ETI ETI JULY 1980 73 BUILD YOUR OWN METAL DETECTOR The latest from the U.S.A. VLF/TR VCO/TR IB/TR BFO PINBALL WIZARD HAND HELD GAMES * Still available * Featured in Nov issue of E T I Pre -aligned search heads - test equipment not Supersonic Mastermind E21.00 Home W Game -B r W Kra required. Literature available in return for SAE. Galaxy Invaders . . (22.95 Marvel Soccer E21.50 Basic Kit£28.90 Manuals and parts sold separately: write or ENTERPRISE 4 in 1 (24.95 Contains everything except box and con- phone for price. Export welcome: write for 3 Games and calculator in one trols quote. 'Electronic Mastermind . (12.90 Box & Controls - £6.50. Mains Adaptor U F.O. Master Blaster . £24.95 - 0.90 Amaze-A-Tron maze game E18.95 Play 7 games with 4 options on each Touch Me by ATARI (like Simon) (26.95 game Football (two players) £24.95 4 -Pinball games 2 -Basket. 1 -Breakout ZAP missile game E11.95 Versatile car alarm kit E18.90 'DIGITS (like Mastermind) £14.95 See review in Hobby Electronics ALL GAMES HAVE SOUND EFFECTS November EXCEPT' CHROMA CHIME 24 tune door chimes kit Shadow VLF/TR. Full s E10.75 Built E15.95 specification discriminator, not C B Aerials and Accessories lust ferrous /nonferrous indica- tionIt works by measuring the conductivity of the target, now you can COMPUTERS - Home. reject nails bottle caps even aluminium Inn end ring Pull tabs! Full ground effect ATARI video Business etc. exclusion over normal or high per- £550.00 meability soils. computer PET 8K The head is thermally end capacitively shieldeJ. PET 16K £670.00 4 modes- deepseeking VLF plus 3 TR discriminating ranges Shadow SORCERER 8K £747.50 Push button "memory" tuning. Performance equals SPACE INVADERS CART (29.95 SORCERER 16K (874.00 commercial detectors coking E2001 As descnbed in ETI. TR/1B STAR CHESS T V Game £63.35 £887.75 Complete kit now only E67.67 lass. VAT 6 post!! SORCERER 32K DATABASE Prog. T.V. Game SUPERBOARD II 4K E172.45 Individual pares. Search head E21.33 PCB E6.130 Case (5.33 Adjustable shaft essy. E5.10. LM393 NEW £89.95 Cl 12. Manual (gives more info. then ETI article - and extra function)E1.12.Allane. VAT & post! (Other NEW £59.95 UK101 Kit 4K . £226.85 parts also wadable separately) CHESSMATE B Level Built 4K £286.35 CHESS CHALLENGER 7 £99.00 ..... TRS80 Level 2 16K (409.40 Shadow TR .0111 (illustrated). A true transmit receive/induction balance detector at a budget price for CHESS CHALLENGER 10 £160.00 anyone who doesn't need discrimination. Waterproof and thermally insulated search head. Good 51/4" Floppy Drive E288.65 VOICE CHALLENGER . (219.00 Dual Drive E506.00 sensitivity. Built-in speaker end headset jack. Complete kit E26 + VAT (post Si Pkg. Et .60. CHECKER CHALLENGER 2 (54.00 NASCOM 2 Kit E339.25 CHECKER CHALLENGER 4 £90.00 Shadow TV /VCO. An advanced version of the TR /113. Use as a sensitive 1B machine or switch to VCO 2 Built (396.75 mode when the sound changes to a varying pitch, allowing easier use over mineralised ground and ZODIAC Astrology Computer enabling detection of negative high permeability anomalies. Kit price E29 + VAT (post (1.80. NEW E29.95 HEATH WH89 E1,805.00 HEATH WH14 Printer E586.50 Snooze Alarm £14.90 Metching stereo headphones for ell Shadow models E4.90 Softy Kit VAT (post paid). EL -MAC 5MHz Scope E139.90 £115.00 Softy Built RADAT 10MHz Scope (169.00 (138.00 Beginners RIO model. A very detailed assembly manual and pre -wound coils make this en ideal first Intelligent EPROM Programmer proper Simple high efficiency circuit. Full size (not a toy) but weighs only 300gms (I 0.5oes) with battery! FREE STETHOSCOPE HEADSET with every order. ALT] kit: E12 + VAT (post E1.80). Padded high Z PRINTERS: FLOPPY DISC: 60085 headphones E4.50 + VAT (post paid) S.a.e. Enquiries. Please allow up la 21 days for delivery. All prices inc. of VAT Shen 1(11. Consists of the (hard to find) hardware items. for detectors of your own design. Fully adjustable shah with handle. search heed mouldings lint. diem 1135mm) with hinge assembly, special clips to mount your own control housing (any boa is suitable) Completely non-metallic and undrilled. With assembly instructions £6.25 + VAT (post £1 50) (ETI), 1 Green Lane ALTEK Walton -on -Thames Surrey 61 BROAD LANE,.1.0 LONDON N.15 4DJ Order by post or phone (24 hours) Access & Visa Cards quote number Callers by appointment only ramose Day 01-808 0377; Eve 01-889 9736 Phone (093 22) 44110 anytime, RECORDING TAPE. Lax isles malar. MOTOROLA PIEZO MOTORS. I.54 Mewl motors OP. Sub milt SPECIAL OFFER DEC TYPE BREAD- ELECTRIC TRANSFORMERS. All2404 DC primary Rig inch115V CC 3 rpm meter 32p supplied unboxed. 7" 12001 (1.00. r BOARDS. Niue INC "A' wile 2 16 ple DR (postage per traosfermeris slime is II 45IT' 3600' 1560. SLINK CASS- TWEETERS Replaces. 8 track125 DC motors 55e carriers 13.95. Nitro DEC "8 ' with 2 brackets atter price' MINIATURE RANGE Gored ems mama 2: rpm 75p 1154 AC ETTES. C60 101w 0.75.0010Yr 0.65. integral16 pioOIL carriers 0.95 Belk 6-061 1001m. 9-09V 75ea. 12-0-121 50mo LOW COST irat TAPE SPIICER ELM. KRTIOI MrMeler. 1.000 1 rpm mow 95p Cassel. molars5 8VDC b ...... appreabilely lull anginal all 79p tech 1151) 121200ms 75p (I 5p1. Ofi opr. ACrfIC Wells. teguip elites price. 70p 91 CC Cassette molars 95p DS280rea £1.20 (2101. VI 500f. TITO 150ma DC cereal. Resist. IV Cassette motors new standard laptype inel a 24 035145p)1214A 12 14510 site 0255. 0-100K. 14.35. 11 25 15.0-154 IA 52.25 )45p(30-0-301 I11A5 f2.85 COOLS. SOLDER Sacker. used watt. )54p) 2041201 20/ 0.65 15401. 0-12-15.20. ten MAC Ella Side cellars 5" E1.45. 301 2A 14.75154p] 201 258 12.351541. Moth 5' El 45. NEON DRIVER r LONG COPPER LAMINATED PRINTED 311 erect radiation lye. L3.65 B UZZERS. Nieinere solidslate typo. 591. MIYAMA 16 pin IC Intl clipf 1.65.5 CIRCUIT BOARD. Fibreglass Single Sdoil 3.5" San F taper les C4.50 TRIAC XENON PULSE TRANS- 33/(17,415mm. 7011 al 3 NM. 15me frail. PIECE precision screwdriver sets. twe lapproxtea thick)150a95rnm 40p. dmorlual handles. FORMERS. II [GPO style) 32p1 1Mus Isub Weal. 4-1510C 75p each. LOUD 12 roll 11.05 JUMPER TEST 200e90. 551 250t 145mm 65pDouble. pale monitiog 65p lezzar 50 x30eam 63ptartars 125 DC LEAD SETS 10 pairs of leads with insulated seed Fibreglass Imm Mick.Ills 135ma Marmite alarm areas ETAS &volt version con each end 90p. CRIMPING TOOL. 45p. PAROLIN BASED TYPE. 17mm thick'. PIEZO TWEETERS. require ne or 55p. 125 DC SIREN. all metal rotary bps. high combination type ten crimping red. blue and 180s 135mm 40p 211012110mm 50p sod can be load with systems op to100 pitched wail. 0350. (eery Wm Wes. 121 yellow terminations also incorporates a wire vette. Freeway reeponse 3.8 te a. red plastic wit will nand. Bracket. tripper b gauged and wire cutter muffled FA x Ithem 14.50. handles only 12.30. PROJECT BOXES. Sturdy ABS black p155110 bean with brass marts end MI 11115S M,METER. 2.000 TAPE HEADS. Mono cassette £1 .75 RANK ARENA Per. cartridge preen 75x56x35fne 65p 95 x7x 35mis 75p oarIRV AC DC Volts Stereo cassette 13.90.Slanted 8 trick 115,49)437mm Rip. RELAYS. 2 types nib operate on 121 DC. Other module,suitable for didelt 100ma DC Resistance O. MICROPHONES. Min.liepin Ono.user stereo IT% BSH MM 1330itrack 50p. 10K 0-1 MEG £5.50. sealed plastic cased types. 1-350 olien with cartridges. new supplied wilk coansclaia deaf and battery Wattled' £4.95, Low cosi BS SIPS itack 02.10 TO IS dial head VERO NANO HELD BOX. Wats MS Zilin 2 eels 5 amp contacts 75p. 2-1.000 ohm deist's. II 95 condenser EGM105 Omni. 600ohms. on/off assembly 2 hods both / track RIP will built x 3.71. lap* r with screws 68p each with 2 changeoverI amp contacts 75p. switch slandird jack pig 52.95. EM507 in erase f 1 25 Condenser. uni. 6013ohms. 30113101/. highly VERO POTTING PLASTIC Sores wan lid pooled metal body. 57.95. DYNAMIC W. asd urn: 70,4 50x 20mm TINNED HEATSINKS. Suppled WHIM black 43p microphone dual imp 600ohms or NIA E MI SPECIAL OFFER SEMICONDUCTORS. 4am lock 27me high. /5x 124me Op. 70.15114. attractive black renal body. 07.75. 1500124mm 954. Smaller mew 2.70 295062 SCRs 18p 84504 ape isolator 25p E M 506 Condensercardiorl um, 600ebee or 5.151. 75x 1080 48p TRANSISTOR 333130 95p TBa800 50p TOAI 151 25p 741 56. hem chromed copper ma. 112.95. SWITCHES. Sal. sit. Tsiglet. (PET SOCKETS T05 or 1018 9p each. TO3 type Op 72335p NE555 24p A0161,2701 pair DYNAMIC P AMike mobile robe MC.. 8x5 x Tem. 42p. DPOT 1001 x7) 55p. OPOT Curs .11112x1Ixlimel 77p. 1541 ma. 2113055 389 114005 10 tor 35p. 80238 28p thumb switch 50k imp. 03.75. CASSETTE Y11360 M/ METER. CLIFF CLICKTEST 13 amp moat colon 80438 28p 7410 359 211414 15p TI1.305 replacement microphone with 151.5 pleas 20.000 opt.Ill AC/OC PUSH SWITCHES 116x red lap. le. Ideal for workshopetc provides rapid Apia numeric display £2.50.MAN3A 3me fl 35 INSERT crystal replacement MO 250ma DC. 4 resist pain a maks 15p ma pad RI Sant and sate mains connectionlough moulded LEO displays 45p Mm LORs 30p ZEDS 01" 35x lOmm 40p. GRUNDIG (Intel merle. ante rangesit20 Mg.. straw lick vlsyl 17p lack ALUMINIUM PROJECT BOXES. 111 case and lidtvith neon indocalor and lose GUAR 15p GREEN 12pRED 10pInlra-rad WA built in FEE preamp 3-611 DC. f I.00. S.W.G. wile filled lid sad ureter Ail also hes bell -in transistor dor LEO 30p MPU131 PUTS. 40V 200ms. 015. SLIDE SWITCHES el OPP 15x Ix 120 30201 52p. AM 4x3xl.Sla 62p. M3 testerwith leakage and 375mW 15p203773 £1 70. Tem R10311 403021s Me AM Oat x2is 74p. MI5 pin ranges Ell 50 170)1 Power trans 50p TA64443 SCR 45p. 131. Mall mew 13p. 22x13x1ise 13p. 2201301 wits tea IN. Millipsla elder 604031. Sp All Badman FIBS. AV &die ulna III n6110090 I Ime 25p. 006034 21.25. SPECIAL OFFER DEMAGNETIZER. Carved probe type. suitable for reel to reel or ROTARY SWITCHES &alai 3P4W. em. cassette machines operates on 2405 AC only 2P6W aid IMP MI 35p lea El 95 NEW STOCK ITEM - We ire law Make, ANTEX SOLI/ENING IRONS. All 2404 AC. low mini Waddell drills. those are a MIMIC 'Swath G.95 Motel IC% 17 watts anima Bnlisheada tool. Awl le P.C. E3.95p. lade 1125 25 walls 13.95pST3 LEO VU METERS. Utiloresophisticated SEKBERMG MON STAID. nits all Wee ens POWER SUPPLIES. Switched typo plegs TIAK500 M. METER W ard drilline. model makers etc. They 16 pin 0.1.1. SWITCHES dray 42p lack. IRV AC DC legic corer re circuit with abuslabie rise lad 1196. late a13 amp swill hes 3-4. 5.6. 7 5 and 9 30.000 oar operate es 121 OC. Oralkilsupplied e decay times na extern' "wader Spec yen 0 coutel either100 or 400ma lollsDC cereal to 12 RIBBON CABLE Ilway single core MIMI- plastic king. use. with drill and21 Response -20111 to100101z Tolerance switcholle 5145. HC244R mabilisee power amps Resistance to 60 acc ..... les. drills. "Wars. 'emus. lure 12p per melt meg in4 rangesalso las within 1011 wenn en 12 I5V IC 82mm aapely 34 7.5.95 DC al 4015na has polarity Milers. etc. meffele kit only 114.25. Drill long 54min hqh reversing andon oldswitch andisfully 11111 in buzzer for cot Attain. AA sin1.2 volts 500ma ELIO MURATA TRANSDUCERS. REG/ENDER. miff 17/5 Drill Mena Is suit vortical drill MONO VERSION 16.95 regulated lo give exact voltage (roe no toad lowly testingt20.95 mass f12.95 bestow Dbl. each or 4 tor 53.95. 004011. 40KNZ 03.50 pair. STEREO VERSION DO 95 loa maximum current f5 50 Terms. Cash with order (official orders welcomed from PROGRESSIVE RADIO colleges etc) 30p postage please unless otherwise 31 CHEAPSIDE, LIVERPOOL L2 2JD shown.VAT inclusive prices. S.A.E. for illustrated lists. ALL ORDERS DESPATCHED BY RETURN POST 74 ETI JULY 1980 Microcomputers are coming - ride CAMBRIDGE Self- the wave! Learn to program. LEARNING Instruction Millions of jobs are threatened but ENTERPRISES Courses millions more will be created. Learn BASIC -the language of the small computer and the most easy -to -learn It's faster and more thorough than classroom learning: you pace computer languageinwidespread yourself and answer questions on each new aspect as you go. This use. Teach yourself with a course by gives rare satisfaction - you know that you are 'really learning and which takes you from complete without mindless drudgery. With a good self -instruction course you ignorance step-by-steptoreal become your own best teacher. proficiency with a unique styleof graded hints.In 60 straightforward Understand Digital Electronics lessons youwilllearnthefive In the years ahead digital electronics will play an increasing part in essentials of programming: problem your life. Calculators and digital watches mushroomed in the 1970's definition,flowcharting, coding the -soon we will have digital car instrumentation, cash cards, TV program, debugging, clear messages from friends and electronic mail. documentation. Harder problems are After completing these books you will have broadened your career provided with a series of hints so you - prospects and increased you knowledge of the fast -changing world never sit glassy -eyed with your mind a blank. You soon learn to tackle around you. really tough tasks such as programs for graphs, cost estimates, DIGITAL COMPUTER LOGIC AND compound interest and computer games. ELECTRONICS £7.00 COMPUTER PROGRAMMING IN BASIC Thiscourse is designedasan £9.00 introduction to digital electronics and Digilal Computer /ter*? Book t Computers and what they do well; READ, DATA, PRINT, powers, brackets, variable is written at a pace that suits the raw 1.003k and names: LET; errors; coding simple programs. No Electronics Book 2 High and low level languages: flowcharting; functions; REM and documentation. beginner. mathematical INPUT, IF. _THEN. GO TO: limitations of computers, problem definition. knowledge is assumed other than the Book 3 Compilers and interpreters; loops, FOR _NEXT, RESTORE; debugging; arrays. use of simple arithmetic and decimals bubble sorting; TAB. andnoelectronicknowledge is Book 4 Advanced BASICsubroutinesstring variablesfilescomplex programming: expected atall. The course moves examples: glossary. painstakingly throughallthe basic THE BASIC HANDBOOK £11.50 concepts of digital electronics ina This best-selling American titleusefully supplements our BASIC simple and concise fashion: questions course with an alphabetical guide to the many variations that occur in and answers on every page make sure BASIC terminology. The dozens of BASIC 'dialects'in use today that the points are understood. mean programmers often need to translate instructions so that they Everyone canlearnfromit - students,engineers,hobbyists, can be RUN on their system. The BASIC Handbook is clear, easy to housewives, scientists. Its four A4 volumes consist of: Book 1 Binary, octal and decimal number systems; conversion between number systems; use and should save hours of your time and computer time. A must conversion of fractions; octal -decimal conversion tables. for all users of BASIC throughout the world. Book 2 AND, OR gates; inverters; NOR and NAND gates: truth tables; introduction to Boolean algebra. FORTRAN COLORING BOOK £5.40 Book 3 Positive ECL; De Morgans Laws; designing logic circuits using NOR gates; dual, input "If you have to learn Fortran land no one actually wants to assimilate gates. Book 4 Introduction to pulse driven circuits: R -S and J K flip flops: binary counters, shift it for the good of the soul( buy this book. Forget the others -this one is registers; half -adders. so good it will even help you understand the standard, dense, boring, DESIGN OF DIGITAL SYSTEMS £12.50 unintellible texts." New Scientist. This course takes the reader to real A.N.S. COBOL £4.40 proficiency. Writtenin asimilar The indispensable guide to the world's No. 1 business language. After question and answer style to Digital 25 hours with this course, one beginner took a consulting job, Computer Logic and Electronics, this documenting oil company programs and did invaluable work from the course moves at a much faster pace first day. Need we say more? and goes into the subject in greater depth. Ideally suited for scientists or GUARANTEE - No risk to you engineers wanting to know more If you are not completely satisfied your money will be refunded on about digital electronics,its six A4 return of the books in good condition. volumes lead step by step through number systems and Boolean algebra Please send me: - to memories, counters and arithmetic ....Digital Computer Logic Et Electronics @ £7.00 circuits and finally to an ....Design of Digital Systems @ £1 2.50 understanding of calculator and ....Algorithm Writer's Guide @ £4.00 computer design. Book 1Octal, hexadecimal and binary number systems; conversion between number ....Computer Programming ill BASIC @ £9.00 systems; representation of negative numbers; complementary systems; binary multiplication ....BASIC Handbook @ £11.50 and division. ....Fortran Coloring Book @ £5.40 Book 2 OR and AND functions; logic gates; NOT, exclusive -OR, NAND, NOR and exclusive - NOR functions; multiple input gates; truth tables; De Morgans Laws; canonical forms; logic ....A.N.S. Cobol @ £4.40 conventions; karnaugh mapping; three state and wired logic. Book 3 Half adders and full adders; subtractors; serial and parallel adders; processors and FOUR WAYS TO PAY arithmetic logic units IALUsI; multiplication and division systems. 11 A U.K. cheque or a U.K.postal order Nor Eire or overseas) Book 4 Flip flops; shift registers; asynchronous and synchronous counters; ring, Johnson 2) A bank draft, in sterling on a London bank (available at any major bank. and' exclusive-OR feedback counters; random access memories IRAMsI and read only 3) Please charge my Access/M.Ch0 Barclay/TrustC/Visa 0 Am Erp 0 Dine, 0 memories (ROMs). 41 Or phone us with these credit card details 0480 67446 (ansaphoneI 24 hour service Book 5 Structure of calculators; keyboard encoding; decoding display data;register systems; controlunit; program ROM; address decoding; instruction sets;instruction decoding; control programme structure. Card No Signed Book 6 Central processing unit (CPU): memory organization; character representation; THESE PRICES COVER THE COST OF SURFACE MAIL WORLDWIDE AIRMAIL program storage; address modes; input/output systems; program interrupts;interrupt Eur, N.AF. Mid.E. add 1/2 to price of books: Jpn. Aus. N.Z. Pcfc add 1/2elswehere add priorities; programming; assemblers; computers; executive programs; operating systems and time sharing. Flow Charts and Algorithms Name are the essential logical procedures used in all computer programming and mastering them is the key to success here as well as being a Address priceless tool in all administrative areas -presenting safety regulations, government legislation, office procedures etc. THE ALGORITHM WRITER'S GUIDE £4.00 U.K. Delivery: up to 21 days for send 50p for 1st cl.p.) explains how to define questions, put them in the best order and draw Cambridge Learning Enterprises,Unit 12 RivermillSite.FREEPOST.St Ives.Huntingdon. the flow chart, with numerous examples. Cambs. PE17 4BR England Proprietors' Drayndge Ltd.. address as above. Reg in Eng. No 1328762 ETI JULY 1980 75 STOCKTAKING CLEARANCE SALE! Wilmslow Thousands of Modules must go at TradePrices DIRECT TO THE PUBLIC RING 01-689 4138 and Order Now whilst stocks last Audio LB31000SLC LB31000SLC SOUND TO LIGHT/CHASER. £20.80 THE MOST ADVANCED SOUND TO THE firm for speakers! c, 12 VAT LIGHT MODULE AVAILABLE, WITH AUTOMATIC SWITCHING TO CHASE $4, UPON ABSENCE OF A MUSIC INPUT. SEND 50P FOR THE WORLD'S BEST CATA- 3 Channels, 1000w each. Fully fused LOGUE OF SPEAKERS, DRIVE UNITS, KITS, Very high input impedance. Electronic filters 5HZ to 70KHZ bandwidth. Operates from 'A to 300w CROSSOVERS ETC, AND DISCOUNT PRICE sound input. Triac zero voltage triggering LIST. Master Vol/Bass/Mid/Treble / Chase speed controls 199.5 z 3cm LB31000SL £14.89 AUDAX - AUDIOMASTER - BAKER - BOWERS & WILKINS - LB31000SL SOUND TO LIGHT. E223 VAT CASTLE - CELESTION - CHARTWELL - COLES - DALESFORD - A SUPERB PERFORMING SYSTEM AT AN INCREDIBLY LOW PRICE. DECCA - EAGLE - ELAC - EMI - FANE - GAUSS - GOODMANS - 3 channels. 1000w each. Fully fused. HARBETH - ISOPHON - I.M.E. - JORDON - JORDAN WATTS - Very high input impedance. Operates KEE- LOWTHER - McKENZIE - MISSION - MONITOR AUDIO - from 1/4 to 300w sound input. MOTOROLA - PEERLESS - RADFORD - RAM - ROGERS - Third order filters. Zero voltage fired. Master /Vol / Base / Mid /Treble controls. RICHARD ALLAN - SEAS - SHACKMAN - STAG - TANNOY - VIDEOTONE - WHARFEDALE. LB81000LC CHASER An 8 channel chaser with speed and chase return delay. Can be wired as a 4 channel. (Rope light controller.) WILMSLOW AUDIO 1000w per channel. CMOS circuitry £18.43 Zero voltage fired. Can be footswitch 2 76 VAT triggered. Additional modules can be SWAN WORKS, BANK SQUARE LB81000LC cascaded to form 16, 24. 32 chap ect WILMSLOW, CHESHIRE SK9 1 HF 19 x 9.5x3cm LB41000LS LB41000LS SEQUENCER Tel. 0625-529599 FOR MAIL ORDER AND EXPORT OF LOGIC RANDOM SEQUENCER, WITH TWO £12.18 DRIVE UNITS, KITS, ETC. SPEED CONTROLS OFFERING A WIDE E 1 83 VAT RANGE OF EFFECTS. 4 channels. 1000w each. CMOS circuitry Zero voltage fired 20 v 9.2 x3.5 cm Tel. 0625-526213 (SWIFT OF WILMSLOW) FOR HI -Fl 1E131000LO and AND COMPLETE SPEAKERS. LB3100OLD 11000LD DIMMERS. FULL POWER 3 & SINGLE CHANNEL LIGHTING DIMMERS TFHOERA TURSEE SI /NS CC IHUOBOSL/SP,UEBTSC/. CALCULATORS 1000w per channel. Fully fused phase controlled Full input and individual Triac filters CASIO FX 501/502P PROGRAMMABLE Lcd (Featured Feb ETI) LB31000LD £10.22 LB1000LD £4.66 FX 501 P 10+2 digit, 128 step. 11 memories E43.43 E1.53 VAT 70p VAT FX 502P 10+2 digit, 256 step. 22 memories E50.83 NEWI LBACOI FA1 Adaptor cassette interface £1 7.35 3 -channel active crossover module with 18dB boost MASTERPACK 150+ programmes on tape with manual E13.87 control of lift Bass mid or treble bands. Available with FX501 P+FA1Masterpack £68.65 crossover frequencies of 200 or 300 and 2k or 3kHz 502P+FA I 4-Masterpack £86.04 please specify) - £12.46 + £1.87 VAT. TEXAS TI51-111 32 step I 0 memory £25.17 LBPSUI I :15v supply for LABCOI £4.31 + 65p VAT TEXAS TI53 Lcd 32 step constant memory £22.57 'TEXAS TI57 50 step 8 memory £23.44 POWER AMPS 250 150. 100 & 25er. etc. al 'TEXAS T158 480 step 60 memory E58.22 RUGGED TOUGH DEALING AUDIO ROPE LIGHTS NOW TEXAS T158C as above with prog retention £73.87 POWER AMP MODULES. AVAILABLE! COB TEXAS TI59 960 step 100 memory mag card E150.39 8 metres in lengthRed /blue,' TEXAS PC100C Printer for 58/ 58C/59 rEilb0 E136.48 LB250 B10,1 1625 green/yellow. R R.P £45 -1- TEXAS PC1000 IF ORDERED WITH 58/58C. 59 E130.39 IOHZ to 25KHZ IOHZ to 25KHZ IOHZ to 25K/1720HZ to 60KHZ E6 . 75 VAT. Complete Control 'INCLUDES - rechargeable battery pack /adaotor,icharoer S/N 110dB S/N 110dB S/N 110dB S/N 90 dB PROGRAMME LIBRARIES FOR T11513/811C /59 THD 0 1% Units with forward /reverse and THD 0 1% THDO 1% THD 0.07% automatic options from 2 /sec. to AVIATION £22.57 0.5v SENS 0 5v SENS 0.5v SENS 0.5v SENS APPLIED STATISTICS £22.52 £27.48 £18.43 £12.66 £7.79 2/min. R.R.P. EBB + £10.35 VAT BUSINESS DECISIONS £22.62 ELECTRICAL ENGINEERING C4 12 VAT C276 VAT + 1 90 VAT + Cl 17 VAT £22.57 POWER SUPPLIES MARINE NAVIGATION £22.57 PREAMPS Four types of powerful supply units for our MATHS/ UTILITIES E22.57 LEISURE £33.00 LBPA3 Complete stereo disco preamp power amps Consisting of a varnish impregnated mains transformer and rectifier STRUCTURAL ENGINEERING £54.74 system. Comprising of L&R deck mixers, SURVEYING 11 £54.24 board Ruse protected) mic mixer, deck and ',lc tone stages, mic PC100C PAPER ROLLS TEXAS TP30250 10 OFF £19.09 BATTERY PACKS state model or BP number auto fade over decks. PFL. output LBRLDI. Relay de - £6.04 LB250PS £17.04 SCIENTIFICS S DIGIT Led SCIENTIFICS 10 DIGIT Led drivers and its own regulators Dyed speaker connec f 2 56 VAT ring device placed CASIO F068 £16.48 CASIO FX 100 £13.00 LBPA2 General purpose 4 between Amp & LB150PS £12.52 CASIO FX80 E12.13 CASIO FX510 C16.48 CASIO FX81 £18.22 chan mixer/ tone stage Speaker /1 88 VAT E 1 1.26 CASIO FX3200 CASIO FX330 E13 87 CASIO FX5000 10 MEM £24.30 LBPA1 Stereo £4.96 74p VAT LB100PS £10.22 CASIO FX2600 C16.48 CASIO FX8100 £20.83 Hi Fi System Et 53 VAT CASIO FX7100 E20.83 SHARP EL580618 + 2) £15.61 LB25PS £7.79 SHARP EL503 £11.26 SHARP EL5808 034.21 E13.87 El 17 VAT TEXAS TI25 or 7135 (18.48 SHARP EL5812 E16.48 TEXAS TI50 E19.96 NATIONAL NS 108 £15.61 TEXAS TI42 MB A 32 step 12 memory financestars £35.61 LBPA 1 £13.57 TEXAS TI PROGRAMMER £43.43 TEXAS T144 Lcd constant memory statistical I 2 04 VAT £25.17 TEXAS LITTLE PROFESSOR £11.26 LBPA2 £11.97 TEXAS DATAMAN £17.35 1180 VAT TEXAS SPEAK AND SPELL £38.22 LBPA3-M (magnetic CASIO FX5000EP mares printer. List £196.48 E136.48 CLOCK CAULCULATORS deck inputs) £21.36 CASIO M06 micro card watch m leather case £17.35 i'ti VAT CASIO PW81 hourly chime /alarm E13.00 LBPA3-C (ceramic CASIO ML81 hourly chime/2 alarm /tuner /date /musical £19.09 LBPA3-M CASIO ML71 card version of ML81 with 1 alarm C19.09 20 4 x 11 509 deck inputs) £21.36 CASIO A01500 day /date /stopwatch £13.87 + El 20 VAT CASIO A02000 special low price £17.35 CASIO A02200 hourly chimer alarin.'calendar r stopwatch E17.35 YOU REQUIRE A BOARD THAT'S MIGHTY COMPETITIVE, RELIABLE, CASIO MC112 card version of above £17 35 MANUFACTURED FROM THE HIGHEST QUALITY COMPONENTS, OF HIGH PERFORMANCE, TESTED AND INSPECTED, SUPPLIED WITH CONNECTION TELEPHONE ANSWERING MACHINES twin cassette E147.78 AND CCT, DGM AND GUARANTEED. IN TWO LETTERS YOU REQUIRE L & B. P:irCES EXCLUDE VAT PLEASE Ar7D 15% PACKING & DELVERY FREE 45WESTORT Y ROAD For your FREE catalogue. with full spec, send a 12p stamp CALCULATOR SALES & SERVICE Trade and Overseas inguirres welcome L. & B. CROYDON Arrow Works, Arrow Road, Redditch B98 8NN P /Packrng FREE in the UK except power supplies ELECTRONICS IETII SURREY CRO 3EB tf 1 00/ TEL. 01-6894138 Tel. Redditch (0527) 43169 76 ETI JULY 1980 PROJECT AUTOMATIC PORCH LIGHT Take yourself home in style and don't be left in the dark with this ingenious Reader's Design from Mr P. Dakin An automatic porch or outside light is a valuable asset to people who want their homes to have that 'some one about' look, and the convenience of the front door or drive lit when returning home during the HOLE MOULDED INTO hours of darkness. The circuit to be described will turn BLANKING PLATE on a lamp when it is dusk and turn it off at dawn. There is, of course, a master On -Auto Off switch. The unit will handle lamps up to 500 W, with a 240 V supply, 250 W with a 115 V supply, and in the off state draws approx- imately 20 mA. The heart of the unit is the common 555 switching IC, but used in an uncommon configuration. LDR SENSOR Construction Fit all the components except C3, which is fitted after testing. The board is designed to fit into a MK type 2140 surface mounting wall box. The LDR may be mounted into the blanking plate MK type 3827, as shown in Fig.2, or remote from the unit. Vcc - LDR SHIELDING TUBE IF REQUIRED EPDXY GLUE A BLANKING OUTPUT PLATE LEVEL PIN 3 Fig.2. The LDR is mounted in the blanking plate (top). A shielding tube may be fitted if necessary (above). Setting Up and Testing Having built the board, check for solder splashes OV - 4 4 and dry joints. Set RV1 to mid -position, connect a lamp, the LDR and the mains. A WORD OF CAUTION, there is mains and rectified mains on the board, also the tab of the thyristor is connected to its anode. Be careful where Vcc oV 1/3 Vcc 2/3 Vcc you put fingers and voltmeter. VOLTAGE AT PINS 2 AND 6 Now switch on. If the LDR is in a light area, nothing will happen. Darken the LDR and the lamp will light. In- crease the light around the LDR and the lamp will ex- Fig.1. IC1 is used as a level dectector with hysteresis. tinguish. The exact setting of RV1 will depend on the ETI JULY 1980 77 D5 1N4004 R1 10k 0 LP1 3, ICI 555 R5 4k7 C1 SCR1 100n C106D R6 680R D6 T2 470u 2x61C15V2x61C15V Fig.3. Circuit diagram. A common or garden 555 is at the heart of the unit. HOW IT WORKS Figure 3 shows the full circuit diagram of the unit. Light Depen- dent Resistor LDR1 is the sensor for the system. Its resistance depends upon the amount of light falling on it, the more light the loweritsresistance.IC1isused asa leveldetector with hysteresis. The 555 has inbuilt resistence levels of 2/3Vcc and 1/4 Vcc. When the voltage on pins 2 and 6 rises above 2/3Vcc the output, pin 3, swings low, and as the voltage falls below 1/4Vcc the output goes high as shown in Fig.1. RV1 is adjusted so that the unit switches on at the required light level. R3 and C3 form a 10 5 time constant. This is the time it takes for the voltage on pins 2 and 6 to rise to 2/3Vcc, asuming C3 charges from 0 V, and is included to reduce the possibility of false triggering, eg passing car headlamps, or children with tor- ches! The supply for the circuit is via D1 -D5, R1, and regulated by D6. C2 is supply smoothing. The external lamp is switched by the thyristor SCR1. A thyristor was chosen because itis easier to trigger than a triac, and does not have a radio frequency interference problem in this configuration. The disadvantage of this method is that a diode Fig.4. Component overlay. THERE IS MAINS AND RECTIFIED MAINS bridge, D1 -D4, is required, and the bridge must be capable of ON THIS BOARD. handling the lamp current. It was found with early prototypes that mains transients PARTS LIST could cause the lamp to flicker when nearing the lower (switch on) threshold level. A comprehensive filter circuit has been in- Resistors All 1/4W except where stated cluded, comprising D5, R1, C1 and C2. R1,4 4k7 4W (2W for 115V) Any high frequency spikes on the mains supply will pass via R2 1k5 D1 -D5 and be decoupled to the negative side of the supply by C1. R3 100k The impedance of C1 being smaller than the value of R1. Should R5 4k7 the mains voltage fail or fall for a few cycles, C2 would try to R6 680R discharge through R1 and the lamp circuit. D5 and C2 hold the supply high for this short period, D5 being reversed biased. Potentiometers The thyristor used is the C106D sensitive gate type. This re- RV1 100k quires OV8 cathode to gate, and 200 V gate current. It is triggered from the output of the 555. R5 and R6 form a potential divider to Capacitors give approximately 2 V cathode to gate, sufficient to ensure C1 100n 400V polyester reliable triggering. R5 also ensures the gate returns to the same C2 470u 25V electrolytic potential as the cathode when the output of the 555 goes low, C3 100u 25V electrolytic thus ensuring the thyristor remains untriggered. The circuit may be modified for 115 V operation by reducing Semiconductors the value of R1 to 4k7 (2 W). The other components remain the D1 -D4 1N5404 or similar same. However, because of the reduction in the supply voltage, D5 1N4004 or similar the maximum wattage that can be switched is reduced to 250 W D6 BZX61 C15V the current through the diode bridge D1 -D4 and thyristor SCR1 SCR1 C106D or similar being 2 A maximum. IC1 NE555 LDR1 ORP 12 Miscellaneous BUYLINES PCB, PCB mounting terminal block RS No. 423-762, Surface mounting box MK list No. 2140, Blanking plate for box MK list Allcomponents used are standard and should be readily No. 3827, 2 screws M3.5 Pan Head, Small heat sink (aluminium available from most mail order stockists. 1mm x 25mm x 10mm). 78 ETI JULY 1980 PROJECT: Automatic Porch Light O AUTO - UNIT E LDR PORCH NO LIGHT SENSOR OFF WALL Final Installation SWITCH When the unit has been sucessfully tested, it can be AUTO -ON mounted in an appropriate place. The method of con- nection is shown in Fig.5. The best position for the sensor is an outside location away from the influence of traffic, Fig.5. Method of connection of the unit to the house mains wiring. street lamps and neighbours' lights.If a suitable loca- tion cannot be found, a small tube to shade the sensor can be fitted which will increase its directivity, asshown location of the sensor, and is best set when the unit is in Fig.2. This completes the construction of the unit. finally installed. RV1 and R4 values give ample adjust- If the completed unit is mounted externally, some ment for most situations. If however, the adjustment of form of weather proof seal must be made between the RV1 is insufficient in the clockwise direction, the value box and the blanking plate. The best type of sealer to use of R4 can be increased to 47k. When all is satisfactory, is silicone bath sealer. Spread a small amount on the fit C3. Recheck that the unit does not respond to short mating surfaces of the box and tighten down the plate. dark or light periods. The sealer will harden and prevent water entering. ETI COMPONENTS IN 4148 0.09p. 154002 2.9p 723 14 dil 33p. NE555 8 dil 24p. 741 8 dt1 18p. AT BLINKIN' LAST! TV GAMES bc547. tic549. bc182. bc184, bc212 bc214, AY3-8500 chip bc548 5.5p. top31c, hp32c 36p. tip41c 40p. £6.96. Kit E4.26. bd132 27p. plastic equiv bcy72 4.5p. fuses COLOURBOARD II Stunt cycle AY3 20mm x 5mm cartridge .15.25,5,1, 2,3, 8760 chip £13.71. 5Amp quickblow 1p. resistors 5% 1/4W E 1 2 1011 THE NEW 50HZ COLOUR VERSION OF OHIO SCIENTIFIC'S SUPER - kit E4.95. 10 game to 10M 1p, 0.8p for 50+ of one value. polyester BOARD II IS HERE AND LIKE A TON OF BRICKS DOWN CRASHES THE paddle 2 AY -3 8600 capacitors 160V .015, .068m1 2.6p,1 m1 4.0p, PRICE OF STANDARD SUPERBOARD II. chip £10.25, kit Olmf 3.0p, 022, 033mf 3.3p, 047nd 4.0p, E7.03. Racing car 15,33mf 4.9p, 47mt 8.0p. polystyrene 50HZ UK BLACK AND WHITE SUPER - chipAY3 8603 capacitors El 2 63V 10 to 1000pf 3p, 1n2 to1 On BOARD II £1 3.6 3. Modified 4p. ceramic capacitors 50V E6 22pf to 47n 2p. shoot kit E5.28. Col- electrolytic capacitors 50V 5,1, 2mf 5p, 25V 5. £159.95 + VAT POST FREE our generator kit 10inf 5p, 16V 22, 33mf 5p, 47, 68mf 3.5p, COLOURBOARD II £205 + 15% VAT £9.05. 100mf 6p, 330, 470mf 9p, 1000mf 11p. zeners 400mw E24 2V7 to 33V 7p. preset pots sub- MAINS TRANSFORMERS miniature 0.1W bora or vett 100 to 4M7 7p. 6 0 6V 100ma 80p,1 VI a E2.60. 9-0-9V 75ma potentiometers 1/4W 4K7 to 2M2 log or lin single 80p, la E2.40, 2a E3.94. I 2-0.12v 100ma 99p. 27p, dual 71p. 'A" red LEDS 9.7p. is sockets 8 d,l THE UNIQUE SPECIAL 8.7p, 14 dil 10.1p, 16 kit 12p. OFFER YOU CAN'T RESIST la £2.90. 15-0.15V 10 (3.15. * * * * * * * * * * * JC12 and JC20 AMPLIFIERS Integrated circuit audio amplifier chips with data BATTERY ELIMINATORS If bought with superboard or colour* and printed circuits. JC12 6 watts £2.08. JC20 3 way types with reducedeatthe 10 watts E3.54. switched output Pces7 a rd :h7vnrst7 Items Also at sold separately * and 4 way multi sat the;racketad prcesAdi15%VAT lack - 3, 41/216V CONTINENTAL SPECIALITIES 100ma E2.67, 6 4( (E9.95). 4K extra ram £19 (E24). PRODUCTS 71/219V 300rna Case £19 (E24). Cassette recorder EVP300 £8.82. EXP350 £3.65. EXP325 £1.84. E2.84. 100ma 4E £13 (E15). EXP650 E4.14. EXP48 £2.64. radio types with press -stud connec- * * * * * * * * * * * STABILIZED POWER KITS tors 9V E3.77, 6V The first price is for kit without transformer. the E3.77, 41/2V bracketed price includes transformerTTL, E3.77, 9 + 9V £4.99, 6 + 6V SINCLAIR PRODUCTS COMPUTER GAMES computer supplies 5V 2A E3.13 (E7.44), 5V 4A £5.12(£12.60). 8.way types 3/41/2/6/71/2 191 £4.99, 41/2-i-41/2V 12/15/18V 100ma £1.84 (£2.60). 1A £3.30 £4.99. cassette (E6.50), 2A E5.60 (£9.84). Variable voltage recorder mains unit models 2.18V 100ma £1.84 (E2.60), 1 30V 1A 71/25 100ma with 5 pin din plug £3.30 (E6.75), 1 30V 2A £5.60 (E12.10). £3.67. fully stabilized type 3/ PRINTED CIRCUIT MATERIALS 6/71/2 /9V 400ma PC etching kits - economy £2.42, standard £5.97. car conver- E4.76. 40 sq ins pcb 45p. 1lb Fedi E1.50. Etch tors 12V do input. resist pens - economy SOp, dale 849. Drill bits output 71/2V I 32" or lrnrn 34p. Etching dish 92p. Laminate 300ma £1.19, cutter E1.20. output 3/41/2/6/ 7 1/2 /9 / 1 2 V PFM200 £51.95, case E2.07, adaptor £4.20, con. Chess challenger 7 (illustrated) £84. Chess champion 6 BI-PAK AUDIO MODULES 800ina £2.75. rector kit £13.95. Microvision TV E89. mains adaptor £49.95. Checker challenger 2 £46. Star Chess £62. £6.69. PDM35 E34.23, mains adaptor £4.20, case AL30A £4.53. Grandstand video entertainment computer E79.95. PA12 £9.31. BATTERY ELIMINATOR KITS £2.07. DM350 E76.70, DM450 £102.17, DM235 Videocans £12.60. Phillips G7000 Videopak home £55.55. Accessories for all 3 models - rechargeable PS12 E1.75. 100ma radio types with press -stud connectors computer E139. Video yaks E12.95. Atari Videocom 1538 E2.70. 41/2V £1.49, 6V E1.49, 9V E1.49. 41/2+41/2V batteries £7.99, mains adaptor; charger E4.20, case pater £129. Canridges £14.85 (except chess E43.95 £9.90. Enterprise prog calculator £19.95. New SC 110 S450 E27.90. E1.92, 6+6V E1.92, 9+-9V E1.92. cassette type 10MHz oscilloscope £144.95. and backgammon £33.95). AL60 £5.62. 71/2V 10Orna with din plug £1.49. heavy duty PA 100 £19.24. 13 waytypes41/2/6/ 7/81/2/11/13/14/17/ SPM80 £5.26. 21 25/28/34/42V 1A £5.52. 2A £8.80. car BMT80 E6.08. convertor input 12V dcoutput 6/71/2/9V lA Stereo 30 stabilized £1.35. SWANLEY ELECTRONICS £23.94. Dept. ETI, 32 Clok1441 Road. Swenley, Kent 898 AL80 £8.56. S-DECS AND T-DECS S Dec £3.79. T Dec £4.59. u DecA E4.69. Mad order only Please add 35p postage Ppoes include VAT unless slatedLists 27p post Iree Overseas U Dec8 £7.16. 16 d,l adaptor E2.31. customers deduct 13 xOfficial credit orders welcome 79 ETI JULY 1980 POWERFETS Some day all power transistors will be made this way! MONITORS VDS ID POISS BOSON CHANmax V max Amax W Type Case Price B0512 60 15 10 t(3.5) 10202 85p MONITORS BD522 60 1.5 10 2.5 10202 sop VMP4 60 2.0 25 2.0 380-50E 1250p VN1OKM 60 0.5 1.0 4.0 7092t 55p MONITORS VN64GA 60 12.5 80 0.3 103 750p VN67AF 60 2.0 15 2.0 10202 75p 2SJ49 140 7.0 100 1.0 103 395p 251(134 N 140 7.0 100 1.0 TO3 395p .1,13 protected tour selection. VN/VM, 96 -page Design Cat. 20p. Haat clips 10202 12p, T092 Sp. MANUFACTURERS/DESIGNERS. We will be stocking Powerfets by IR, TI and Inter- Semi professional or sil as well as by Hitachi. ITT and Siliconix. We can advise you on applications and type selection. supply samples and quantities. professional available REMEMBER Powerfets need virtually no drive current, switch in nanoseconds, and are from stock. 2nd breakdown free, etc. etc. CA3026 70p HI-FI ON TWO CHIPS SCOPE TRACE DOUBLER P.C.B. Monitor PCB's including CA3080E 70pHAt 2017 (Preamp 0 001% distortion Built CAN shift. than select. choprate Transformers and Tubes CA3140E 38p83dB S/N in phono application) 99p HAI 397 (Poweramp 20 watts in 80 controls and instructions. Useful dis also in stock. DAC08 250p0.02% distortion ttyp)195p play from DC to 10MHz Runs from9, DM2502 555p Both with data and circuits battery E9.96 LM308 50p POWERFET AMPLIFIER semicon- LM3900 43p ductor sets High power designs offer. VCA High quality design offers Phone or write for MC3401 30p mg very low distortions attenuation from 0dB to details. NE529 145p'80 wan If THD 0.008%) E11.76 -90dB. S/N 90dB. THD NE555 25p '120 watt (17HD 0 004%) E16.65 0.01%, B.W. DC to 100KHz SAD1024 1050p (with circuits) 'into 80 fat all powers and all audio Complete component set and SD532 30p frequencies. circuit £2.25 TDA1022600p TL081 29p ADVANCED DISCRETE TL082 55p BIPOLARS TL081CP 23p1 CROFTON 2102 80p 2SA 1083(P) t60v, 100mA Sp. price Id 30/6/80. 401113 17p 2SC2545(N) NFO 2c18 19p 2 p S ADC chip set (DAL08. 709 15p 2SA872(P) 90v 16p DM2502, NE529) with data 710 25p 2SC17754(N) 120v 50mA, 17p E9 ELECTRONICS 733 50p 258716A(P) 140v 19p FX309 ("Single bit" A/D. 741 18p flow Cob 1p8 typw low distortion) D/A. Store speech in RAMs) 78105/12 29p with data £7.50 Crofton Electronics Limited Brief data on everything in newlists S A E 35 Grosvenor Road, Twickenham, Middx. P&P 30p. Mail order only. Prices inc. Tel: 01 891 1513 Tel. 01-800 6667 367 GREEN LANES J. W. RIMMER LONDON N4 1DY MAIL ORDER ONLY LF351N 44p 4042 70p 7472 19p AC128 20p BD121 /3 75p TIP3055 55p LF356N 85p 4043/4 88p 7473 *16p AC153 25p 8D124 81p ZTX107/8 12p 30p 4047 92p 7474 *17p AC17 ZTX109 12p DELTA TECH &CO. LM308NLM301AN 55p 4048 55p 7475 26p AC1876/8 22p :g1135to 35P ZTX300/1 14p 62 NAYLOR ROAD, LONDON,N20 OHN LM318N 120p 4049 35p 7476 25p AC187K 30p 80140 35p ZTX302/3 18p LM318H 120p 4050B 44p 7480 32p AD149 65p 8E178 30p ZTX304 23p Please add 35p for P&P LM324N 57p 4066 50p 7485 80p ADI61 /2 40p 13E180 34p ZTX3I 1 18p LM339N 52p 4069 *16p 7486 18p AF114 30p 13E181 Sp ZTX341 22p 7812/15 65p LM348N 90p 4070B 20p 7490 *22p AF124 35p BF183 349 ZTX500/ 1 15p LM377N 175p RESISTORS (5./o E12) 7818/24 65p 4071/2 20p 7491 57P AFI 25/6 35p 8E184/5 25p Zi X502 20p 7905 is, LM380N 90p 4073 20p 7492 30p AF127 35p 8E194 12p ZTX503 17p 10 Ohms to 10Mohms 1.5p LM381N 120p PRESETS (.15W HORIZONTAL) 7912 /15 75p 4081/2 20p 7493 *20p AF139 40p 8E195/6 12p ZTX504 24p 7918 / 24 75p LM382N 130p 4086 80p 7494 30p AF239 44p 8E197 12p 2N696/7 20p 100 Ohms to 2 Mohms 7p LM1310N115p POTENTIOMETERS (WW) 4510 100p 7495 40p BC107/8 10p 8E22413 14p 2N698 20p OIL SOCKETS LM3900N 55p 45118 "70p 7496 45p BC109 10p BF244B 35p 2N706 14p Linear & Log Scales LM3909N 75p 4.7KOhms to 2.2Mohms 8 pm ri7 p 4516/8 100p 7497 200p BC117 23p 8E258 28p 2N914 20p 30p .9p MC1496P 80p 100p VEROBOARDS (.1" COPPER) 14 pin 4520/8 74100 6011 BC142/3 30p BF259 40p 2N918 35p 2 5" x 5" 16in *10p NE531 110P TM 74105 43p 8C147/8 10p BFR39 28p 2N1131 20p 55p NE555 22p 22P 3.75" x 5'' 65p 18 Pin 7400/1 13, BC149 10p BFF179 32p 2N1302 /3 35p 22 pin 16p7410720p NE556 55P 7402/3 13p 74109 40P BCI 57 /8 12p BFX29 25p 2N1304 35p ZENER DIODES (400mW) NE566 5V6 5p*2V7 to 33V 24 pin 21p 140P 7404/5 13p 74110 40p BC159 12p BFX84 25p 2N1306 30p Sp 25., TBA6416200P 74118 90P POLYSTYRENE CAP (50V) 28 pin 7406 18p BC167 14p BFX87/8 25p 2N1613 25p TBA800 74121 22p 10 pF to 1000 pF 5p 40 pin 35p 75P 7407 25p 8C169C 13p 13E1'50/1 20p 2N1711 13p TBA 810S110P 7408 16p 74122 30p BC171 10p BFY52 22p 2N I 893 25p CERAMIC CAP (50V) ZN414 100P 74123 45p 33 pF to 4700 pF 3p DIODES 7409 BC173 Sp BRY39 50p 2N2217 18p BY127 12p ZN1034E 220P 7410 13 74125/6 37p BC177/8 16p BSX19 12p 2N2219 23p POLYESTER CAP (100V) 74132 48p 1 nF to nF 0A47 gp CMOS AE 7411 i5," BC179 16p BSX20 22p 2N2222A 23p 0A91 6p 4000 16p 7412 15p 74141/5 46P BC1828 10p BU205 150p 2N2369 17p 100 nE68 150 nE 7lip 74150 220 nE 330 nE 0A200 6p 4001 22P 7413 23p 55P BC182L 7p BU208 210p 2N2484 25p 9pp gp 39p 74151 470 nE. llp 680uF. 131uF 18p 0A202 4002 15P 7414 47P 8C1838 10p MJ2955 110p 2N2646 46p 2.2uFl 22p3.3uF. 15p* 4 7puF: 1 5p* 1N916 sp 40068 70p 7416 20p 74153 43p BC184 10p MJE340 52p 2N2904/521p ELECTROLYTIC CAP (uF /V) 1N4148 4p 4007 *13p 7417 28p 74154 66P BC186 25p MJE2955110p 2N2906/7 21p 1/251047/25. Op 68/25, 100/358p 1N4001 / 2 4p 4008 80p 7420 15p 74155 46p BC207/9 13p MJE3055 80p 2N2926G 10p 1 N4003 5p 4009 40p 7421 15p 74156 42p BC212 10p MPF102 2N3053 .150/25, 160/25 4p* 74157 45p 20p 1N4004/5 6p 4010 44p 7422 lip 38P BC212L Irlp MPF103/440p 2N3054 220/25 10p 470/259p* 74160 70p 40p 640/16.5p* 1000/10 5p* 1N4006/7 8p 4011 22p 7427 20p BC2131 10p MPF105 40p 2N3055 45p 1N5400 130 4012 20p 7428 25p 74161 55P BC214 10p MPF106 45p 2N30558 1000/25 22p 74162 60p 50p 1500/25-20p* 2200/6 3V 10p* 1N5401 14o 40138 35p 7430 14p BC2141 *8p MPSAO6 260 2N3442 140p 1N5402 150 4014 80p 7432 74163 45P BC238 18p MPSA56 74164/5 26p 2N3702 to 1N5404 16p 4015B 75p 7433 24p 56P BC26113 14p MPSUO6 60p 2N3711 11p BRIDGE 4016 44p 7437/8 13p 74166 85P BC301 /3 32p 0C28 92p 2N3772 1200 74 173 OPTO/ RECTIFIERS LINEAR 4017 50p 7440 10p 7811 SC328 17p 0C35 92p 2N3773 250p ELECTRONIC WO2M 20p CIRCUITS 4018 80p 7441 ,s 74174/5 55p BC338 17p TIP29 40p 2N3819 74177 21p 2N5777 55p WO6M 30p 709-8 28p 4019 45p 7442 *32p' 60 P BC461 40p TIP29B 42p 2N3820 40p OCP71 65p 1A/50V 22p 709-T05 28p 4020B 95p 7443 500 74180 355 80477 23p TIP30 400 2N3823 74181 700 ORP12 70p 111/ 100V 27p 710-14 35p 4021 85P 7444 90p 88P BC478 23p TIP3OB 42p 2N3866 *55p D1704 110p IA /200V 32p 741-8 20p 4022 *70p 7445 64p 74182 45P BC261 El= 11P31 /2 40p 74190 2N3903/4 15p D1707 110p 1A/400V 34p 747-14 50p 4023 22p 7446 65p SUPER BC478 T1P33 65p 2N3906 150 0 125" & 0 2" 2A/50V 40p 748-8 35p 4024B 50p 7447A asp 74191/2 5513pP BC479 23p TIP33C 70p 2N4037 45p LEDs: 4025 20p 62p 74193/4 50p 12p 24 /100V 42p CA3018 70p 7448 74195/6 EIC547/ 8 TIP34A 75p 2N4058/9 10p Red 10p 2A/200V 480 CA3028A 85p 4027 45p 7450 10p 7011 BC549 12p TIP3513 200p 74197 2N4060 / 1 10p Green 13p 2A/400V 55p CA3046 50p 4028 60p 7451/3 54P BC557/8 14p TIP36A 200p 2N5457/840p Yellow 13p CA3054 40p 4029 82p 7454 10,,, 74198 1000 BC559 140 T1P368 210p 74199 2N5459 400 0 125" Clip 3p VOLTAGE CA3080E 75p 4030 *35p 7460 130' 80P BCY70 18p TIP41A 60p 2N6027 *25p 0.2" Clip 4p REGULATORS CA3130E 90p 4035 107p 7470 20p TRANSISTORS BCY71 /2 18p TIP42A 60p 7805 65p C431406 40p 4041 75p AC126/7 22p BD115 58p TIP2955 70p . TRADE ONLY 80 ETI JULY 1980 ODIV 5111/111,1[ Ull please. Orders should be sent to: ETI Book Service, Modmags Sales Office, 145 Charing How to order: Make cheques payable to ETI Book Service. Paymen in sterling only Cross Road, London WC2. All prices include P&P. Prices may be subject to change withoutnotice. BEGINNERS, LOGIC Beginners Guide to Electronics Squires £3.45 Logic Design Projects Using Standard ICs J. Wakerly £5.35 Beginners Guide to Transistors Reddihough £3.45 Practical Digital Design Using ICs J. Greenfield £12.70 Electronics Self Taught Ashe £4.60 Designing With TTL Integrated Circuits Texas Instruments £9.35 Beginners Guide to Integrated Circuits Sinclair £3.45 How To Use IC Circuit Logic Elements J. Streater £3.80 Understanding Electronic Circuits Sinclair £4.20 110 COSMOS Digital IC Projects for the Home Constructor Understanding Electronic Components Sinclair £4.20 R. M. Marston £3.95 Beginners Guide to Radio King £3.45 Understanding CMOS Integrated Circuits R. Melen E4.15 Beginners Guide to Audio Sinclair £3.45 Digital Electronic Circuits and Systems R. M. Morris £3.65 MOS Digital ICs G. Flynn £5.25 _COOKBOOKS TV Typewriters Cookbook £7.75 =TEST INSTRUMENTS CMOS Cookbook £8.20 Active Filters £11.30 The Oscilloscope In Use Sinclair £3.10 IC Timer Cookbook £7.50 Working with the Oscilloscope A. Saunders £4.25 Servicing with the Oscilloscope A. King £6.65 IC Op -Amp Cookbook £10.00 Video Cookbook £7.00 Radio Television and Audio Test Instruments King £7.00 TTL Cookbook E7.55 The Basic Cook £4.00 inc. p/p IC Converter Cookbook £9.50 =OP -AMPS Applications of Operational Amplifiers Graeme (Burr Brown) £8.45 = APPLICATIONS 110 Operational Amplifier Projects for the Home Constructor R. M Marston £3.95 Fire and Theft Security Systems B. Weis £2.15 Designing With Operational Amplifiers Burr Brown £18.35 How To Build Electronic Kits Capel £2.35 Operational Amplifiers Design and Applications G. Tobery (Burr Brown) 110 Electronic Alarm Projects R. M. Marston £3.95 £7.55 110 Semiconductor Projects for the Home Constructor R. M. Marston Op -Amp Circuit Design & Applications J. Carr £4.15 £3.95 110 Integrated Circuit Projects for the Home Constructor R. M. Marston £3.95 110 Thyristor Projects Using SCRs R. M. Marston £3.95 =COMMUNICATIONS 110 Wave Form Generator Projects R. M. Marston £3.95 Communication Systems Intro To Signals & Noise B. Carlson £7.65 Digital Signal Processing Theory & Applications L. R. Rabiner £24.40 Electronic Communication Systems G. Kennedy £8.75 COMPUTING & MICROPROCESSORS= Frequency Synthesis. Theory & Design Mannassewitsch £23.80 What is a Microprocessor? 2 cassette tapes plus a 72 -page book Principles of Communication Systems H. Taub £8.40 £12.00 Beginners Guide to Computers and Microprocessors with Projects C. Adams £6.05 =THEORY Basic Computer Games Ahl £5.40 [Introduction to Digital Filtering Bogner £10.60 Basic for Home Computers A self -teaching guide B. Albrecht £5.40 Transistor Circuit Design Texas Instruments £9.75 Illustrating Basic D. Alcock £3.00 Modern Electronic Maths Clifford £6.95 Intro to Microprocessors Aspinall £6.55 Foundations of Wireless Electronics M. G. Scroggie £5.25 Z-80 Microcomputer Handbook W. Barden £7.75 How to Program Microcomputers W. Barden £7.25 Introduction to Microcomputers and Microprocessors A. Barra £8.60 Microprocessors in Instruments and Control R. J. Bibbero £12.60 -REFERENCE Basic Basic J. S. Coan £7.80 Electronic Engineers Reference Book (Ed. 4) L. W. Turner £34.50 Advanced Basic J. S. Coan £7.30 Getting Acquainted with Microprocessors L. Frenzel £7.25 Electronic Components M. A. Colwell E2.70 Electronic Diagrams M. A. Colwell £2.70 Beginners Guide to Microprocessors C. M. Gilmore £4.90 International Transistor Selector T. D. Towers New update £10.20 Beginners Guide to Home Computers Grossworth £4.50 International FET Selector T. D. Towers £4.35 Beginning Basic R. E. Gosling £4.75 International Op -Amp Linear IC Selector Towers £7.65 Microprocessor Programming for Computer Hobbyists N. Graham Radio Valve and Semiconductor Data A. M. Bell £3.60 E7.15 Miniprocessors from Calculators to Computers Heiserman £5.00 Radio, TV and Audio Technical Reference Amos £30.40 Microcomputers, Microprocessors, Hardware, Software and Appli- cations J. L. Hilburn £17.40 Basic Programming J. G. Kemeny £6.70 -MISCELLANEOUS Microprocessor Systems Design E. Klingman £17.00 Electronic Fault Diagnosis Sinclair £3.55 Intro to Microprocessors Leventhal £17.00 Integrated Electronics J. Milman £8.20 Microprocessors - Technology, Architecture & Applications D. R. Practical Solid State DC Supplies T. D. Towers £6.40 McGlynn £9.20 Practical Triac/SCR Projects for the Experimenter R. Fox £2.35 Interactive Computing with Basic Monro £3.65 Printed Circuit Assembly Hughes & Colwell £2.70 Basic with Style P. Nagin E4.25 Software Design for Microcomputers Ogdin £7.20 Microcomputer Design Ogdin £7.25 Microcomputer Base Design Peatman £5.70 Hands on Basic with a PET Peckham £9.00 Basic -A hands on method Peckham £6.95 Fallen behind recent advances? 6800 Software Gourmet Guide and Cookbook Scelbi £8.90 8080 Software Gourmet Guide and Cookbook £8.90 Just starting out? The 8080A Bugbook: Microcomputer Interfacing & Programming Need a decent reference book? P. H. Rony £8.35 8080/8085 Software Design Titus £7.60 ETI Book Service provides an easy 57 Practical Programs & Games in Basic Tracton £6.65 Microcomputer Primer M. Waite £6.50 way of getting your hands Your Own Compqer Waite £1.60 Microprocessor/Microprogramming Handbook Ward £6.20 on the right title. ETI JULY 1980 81 I J111:1H I 411 ,m,,;21101,1101 ililliii RIC acceptL IV t equip gen's, motors, plies, scopes, sig. IdealorwordprocessorcokrapplicationIOs, of now transformers,poweressupt boards, OLIVETTI TE318.yeofrareiesepoanddyence uses. Supplied in good working order. After seeing the printer only variacs, key C.'s, tools. components, + thousandsof efretritspeedevEciyveeer fitg0060 we must be mad asking only 1295.00 can. Fr VV. equipment. I V .D U's subassemblies yourcomputer fails you still have a first class typewritertransistors, microswitches, of our vast range, is ONLY at your disposal' Just a mere fraction other stock lines. callers. ACULAB interface unit for PET, TRS80, SORCERER E165.00 VAT. displayed below: 100'sof bargains for £130 HOW TO OPTO SMA H! SUPER 77 KEY GET HERE + CARR TIL 302/MAN 7 7 segment LED readout common anode direct drive (via KEYBOARD KIT Victoria, London + VAT resistors) from 7447 f1-10 each Bridge or Holborn TIL 119/0072 Darlington onto Viaduct to isolator 3 for E1-00. We've done it again) We've purchased a large quantity of C P CLARE top quality Thornton Heath. The cheapest way to 110 to your computer, 80 TIL305 0.3" 7 x 5 matrix LED keyboard reed switches plus full QWERTY keytop sets and thrown in a PCB to alphanumeric readouts E3.75 each. enable you to customise the keys just as YOU want them, just add and wire an 1 minute from column high quality printer, friction feed, serial PHOTO TRANSISTOR encoder chip and you can arrange ASCII, BAUDOT, anythingl Adding up to a Thornton Heath ASCII in and out, RS232, feather light keyboard, Fairchild EPT-100 NPN silicon 30v quality keyboard which would normally cost around f100.00. Supplied with Station and inbuilt 8 bit paper tape punch and reader. 25ma. 4 for E1.0 layout and assembly info at only £26 .99 f 1.50pp. Supplied in good condition with interface data I.C. AND S.C.R.'s and accessories but untested, unguaranteed. DISPLAY BARGAINS 283001 30v 350 ma 1111822p each 6 for 0100 285061613v800ma 1018 27p each 4 for ROO POWER SUPPLY UNITS What more could you ask for. TRANSISTOR NEVER CHEAPER 211444150v 8 amps 1022015p each 10 for 01.00 5 VOLT 2.5/8 AMP TTL Made for TTL this compact ex 1" Paper tape 75p per roll + pp 40p. All I.C.'s and Transistors by C10601400,, 5 amps 10202 55p each 10 for f5 00 computer systems unit features a 10 amp transformer. DC HURRY WHILE STOCKS LAST. well known manufacturers and fully TRIACS outputs of 5 volts @ 2.5 amps and 7.5 volts @ 5 amps are guaranteed. No fall outs. Comprehensive G.E. 12 amp 600v 10220AB 95p each 10 for [975 available. The 5v output is fully regulated and smoothed data on I.C.'s 15p per type. E.C.C. 1.6 amp 100v 105 38p each 3 for 01.00 with electronic current limiting. May be easily moded for DYNAMIC RAM SCOOP! 2N4351 N channel MOS FET. A.E.I. 10 amp 400y ready mounted on 23- v 23 INTEL 1103A 18 pin OIL 150 ns IK Rams 5 volts @ 7-8 amps. Sold complete with circuit, believed 2N4352 P channel MOS FET. heatsink f 1.00 each 4 for 03.75 working but untested. E8.25 + C1 .60pp. guaranteed full spec. complete with data. 60p each E1.00 per pair. LOW PROFILE I.C. SOCKETS 8 for £2.99 16 for £4.99 HIGH VOLTAGE NPN POWER 00.11 10p each 12 for 01.00 5 VOLT 5 AMP An extremely compact unit measuring 32 for £8.50 64 for £13.99 SWITCHING transistors BVcbo 600v 11 all. 11p each 8 for f1.00 only 125 x 175 x 83 mm, almost fully enclosed with BVceo 500v BVebo 15v 1c 5 amps 16 D.I.L. Gold Plated mil. grade 22p each 6 for f 101 terminal type connections. Features such as adjustable 18 pin DIL sockets 8 for E1.60 Pc 125 watts HFE 60 typ h 2.5 mhz 22 0.1.1.27p each 5 for E1.110 volts and current limit make it ideal for an MPU system. ideal invertors, etc. T03 f1.60 each 20 13 U. 35p each 3 for f 1 00 Sold as new. E14.99 + E1 .60pp. VENTEK WORD PROCESSOR 4 for £5.40. OTHER GOODIES " +"ft "-" 12-15v @ 250 ma. ITT Powercard. VDU TERMINALS BF258 NPN 250v @ 200ma 45p each 283055 IR C.A.) 65p each Measuring only 140 x 80 x 40 mm, this precision totally 3 for E1.08. 216943 R.F.output 10 volts,1 wan up to 1000MHE enclosed PSU should meet all your memory and negative Still a few available. The VDU with the GREEN screen. I.R. BSB01 2.5 amp 100v bridge rec. 0.5 55p each 10 for BCC railrequirements.Individualpots allow independent Made by the VENTEK Co. with the following spec: P.C. mount long leads 35p each 4 for 244304 WN720 F.E.T.transistor 37p each 3 for CI 00 adjustment of both the plus and minus supply rails. 12' monitor, 24 lines x 80 characters, upper and lower 01.08. 1.114.380NISLIMM114 0.11.2 watt A.F. amp Hp Supplied BRAND NEW with circuit and edge connector at case with descenders, 85 + keyboard, auto repeat, IN4998 4 amp 100v P.C. mount diodes each B for MOO only E12.75 + f1.00pp. ASCII, RS232 interface, adjustable baud rates, full long leads 14p each 10 for E1.10. CA30288 DC. 120 MHZ differential cascode amp cursor control, edit function, characterlsl flash etc., LM309K + 5v 1.2 amp regulator f 1.10 El 00 each 3 for E2.50 etc.Latest technology used, mostly 74LS with each 6 for E5.35. CA3011 20 MHZ wideband amp 1099 case 65p dynamic rams. AGFAClOcomputergradecassettescom- each 2 for [1 .00 Supplied in 2 grades pletewithlibrarycases68peach, 10 forE5.50 TMS3114 DUAL MOS 128 bit static shift reg. DC Grade 1 Complete tested and working £275.00 + VAT IN4004 SD4 1 amp 400v diodes 7p 2.5 MHZ El 50 each 4 for E1.25 KEYBOARDS Grade2 Condition as seen or described E225.00 + VAT each 18 for 1.00. NE555 10 for f255 Carriage Extra I.R. 12 amp BRIDGE RECS. 400 volt 6E424 zero voltage switch, mac SCR relay driver Although Grade 1 sold tested and working no f 1 .25 each. 105 can f I10 each 7 tor f6.50 * 76 KEY ASCII CASED * guaranteeoffered.Anyonewithcircuits/ POWER DARLINGTON SCOOP! FSA2719 8 independent diodes IN4148. 18914 At last a coded 75 key cased ASCII keyboard at the manuals please contact us. fA.11000 NPN 60v 90w B amps T03 95p each type in 16 0 I pack 38p each 3 for 0100 286385 NPN 80v 100w 10 amps T03 f1.25 each F703725 4 NPN 50v Mama transistors in 11 right price. Housed in an attractive light grey case, HY GRADE SMOOTHING CAPS M..11030 NPN 60v 150w 16 amps T03 E2.25 each D ;.L. pack 70p each 2 for [1.00 this unit was originally made for ICL for use in air- MULLARD - PLESSEY -MALLORY -SPRAGUE port reservation systems so only the BEST parts 1500m1 100v 60p* DECADE 0-9 THUMBWHEEL SWITCHES. Stackable, gold plated contacts, 3300mf 40v 50p dim. 33 x 43 x 8 mm. 90p each, 10 for E5.50. were used. It has everything, we think, to meet 3300mf 63v 70p" 1 mf 600v MYLAR 28p yourmostexactingrequirements,numeric 10,000mf 15v El j- 22,000mf16v ELIOT Miniature Continental Series 12VDC 4 c/o plug in relays E1.30 each. 100mf 250v 45p2100mf 200v C.2.50T Greenpar 5011 BNC Chass. socket single hole fixing 65p keypad, upper and lower case, cursor controls, Ex equipment tested 1-P.P. 40p C90 Audio Cassettes screw type construction 45p each 3 for E1.00. single 5 volt rail, serial and parallel data outputs, Bulbs 24v 14 watt white frosted S. B. C. 8 for f 1 .00. plus eight LEDs mounted on the case. Supplied Bulbs 12v 100 watt clear, base similar S.B.C. 45p each. with circuits, believed brand new, but may have SEMICONDUCTOR S.B.C. Bulb Holders All steel cad. plated panel mount easily fixed via nut and minor scratches on cases. round hole, ideal disco displays, scoreboards, etc. 4 for El .10. Only £43.50 f1 .60pp 'GRAB BAGS' VMOS VMPI Siliconix T03 power FET 0-60v, DC -200 mhz will drive direct Amazing value mixed semiconductors, include from CMOS etc, C1 .50 each, full date 30p. transistors, digital, linear I. C.'s, triacs, diodes, bridge Heavy Duty Flat Insulated Earth Braid 100-200 amp braided tinned copper * LOW PRICE CHASSIS * recs. etc. etc. All devices guaranteed brand new, full in heavy clear PVC sheath 50p per metre. E6 for 15 metres + PP El per 15 metres. spec. with manufacturers markings, fully guaranteed. BULGIN miniature 6 way male chassis mount socket and snatching free plug 50 BAG E2.95 100 BAGS f5.15 60p each, 2 for E1.10. -TT Red L E D 's full spec. 0.2" 14p each. 10 for El 25 Red L.E.D.'s 9.125" 10p each 10 for 80p1 Dynamic Stick Mica 60000 with built in on/ off switch complete with lead and min, jack plug El .15 each. 10 for E10.00. Keep your equipment Cool and Reliable with our tested ex equipment T05 HEATSINKS "Thermaloy" black anodised press on aluminium finned Muffin Fans" almost silent running and easily mounted. Available in type 18p each. 8 for f 1.00. two voltages. 110 VAC. (5.05 u pp 65p OR 240v A.C.E6.15 pp A special bull purchase enables us to offer the above keyboard at a 65p DIMENSIONS 4i sq. )1 II BURROUGHS SELF SCAN DISPLAYS lowest ever price. 19 coded keys encoded into a direct TR compatible 7 bit output. Features such as delayed strobe.5volt D.C. single rail A masterpiece of electronic engineering. This unit could be described as a miniature operation and rollover protection make this an absolute must for the ELECTRONIC VDU. Module consists of an 18 digit display area, mounting bezel, on board MPU constructor' Supplied complete with connection diagram and edge COMPONENTS character generator and decoder driver circuitry, all measuring only 8.5' x2.25* x1.34'. connector, at a 'secondhand & EQUIPMENT By inputing a 6 bit ASCII T.T.L. code 18 GIANT 0.4' full alpha "no time to test' fl 0.00 + P- P. £1.60 DISCOUNT numeric characters may be displayed simultaneously, price of only addition of external logic enables the unit to scroll ts SUPER CASED VERSION Same as above spec but housed Due to our massive bulk purchasing programme along just like a newscaster. Internal 64 character pa%, tli3,1 in attractive two tone moulded, free standing case. Unit also which enables us to bring you the best possible repertoire, or external inputs for special characters 0,,,,,,V, includes an all TTL parallel to serial convertor (no details' bargains, we have thousands ofI C 's Transistors. c4,32% areprovided.Power requirements+5v,-12, etc Relays, COWS., P C 8 's, Sub -assemblies. Switches, and 250v. SV's,), etc. etc surplus to our requirements Because we Supplied brand new, c'''''t::°:lai £27.50 +P.P. f1.85 don't have sufficient stocks of any one item to complete with data £55.00 fl .25pp. ."ji22% include in our ads , we are packing all these items into the "BARGAIN PARCEL OF A LIFE TIME - BARGAINS GALORE! 5,.,11° ''''rc,Fis:4". Thousands of components at giveaway prices. l''''.:,:414, ?`23550 TOROIDAL TRANSFORMERS Guaranteed to be worth at least 3 times what you In our walk round Warehouse .,,,,,,i,c0:06` pay plus we always include something from our ads NOW open Monday to Saturday 9.30 5 30 2,,°3,'.',:"1 HP 240v ph sec2 v 30, @4 ampstx18v @ 1 amp fl 1 00.1) p 0.951 for unbeatable value, , Sold by weight PE ------dimensions 41a21 15 0 15 @ 2 amps dimensions 3" PR 210v pit sec 2.5kIs f 4.75+pp £1.25 Skis f 6.75+pp £1.80 [405. p.p. 99p sec s TM 740v 110v pri 15 0 15 8vA dimensions 23' 1- f1.95,ip p. 30p 10kIs f11.754 pp £2.2520 kls £19.99+ pp £4.75 All voltages measured off lead. ISOLATED 240v 4 AMP Et 10 AMP EFFICIE NCYSMITHS SOLID STATE RELAYS RADIAL BLOWERS Interface your MPU etc. with the outside world made Are your hot parts sweltering?Then keepthem cool ELECTRONICS with our high elf iciency radial snail type blowers. Made by the famous "Astralux" Co. They consist of a miniature plastic module with mounting holes con- Dept. WW. 64-66 Melton Rd., Thornton Heath, Surrey. MAIL ORDER by Smiths, designed for continuous use in expensive taining a reed relay for isolation, choke and triec. Telephone 01689 7702 or 01-689 6800 electronic equipment very powerful and quiet, gives 12-20 volts D.C. at a few milliamps enable on/ off INFORMATIONmassive air flow to prolong component life and control of A.C. loads up to 10 amps' The 10 .amp Unless otherWise stated all prices inclusive of VAT. Cash with order. Minimum Easily mounted, air ape, nun NEW version should be mounted on a heatsink. 100's of order value £2.00. Prices and Postage quoted for UK only. Where post and 23' x 3'. Ideal linears etc. BAND" uses including power control, lighting, etc. etc. packing not indicated please add 40p per order. Bona Fide account orders Please state 240v or 110V Dimensions: 4 amp, 13' xt of. 10 amp, 13' x 1 minimum E10.00. Export and trade enquiries welcome. Orders despatched operation. 50hz only, .55 4 amp Et 4510 amp £2.10 complete with circuit same day wheat possible. Access and Barclaycard Visa welcome. A £1 .60 82 ETI JULY 1980 ipi: o tz:1 r :As 1JA i : .71----1=.7.-T--Ara VCARIALL THE PARTS TO BUILD THE PRACTICAL ELECTRONICS TRAVELLER RADIO The pack contains all the electronic components to build the p&p radio, you supply only the wire and solder as featured in the fl 75 Practical Electronics March issue. £10.50 The P.E. Traveller features pre-set tuning with five push CONSTRUCTORS PACK 7A button options, black illuminated tuning scale, with matching Suitable stainless steel fully rotary control knobs, one, combining on/off volume and retractable locking aerial and tone -control, the other for manual tuning, each set on wood speaker (approx 6" x 4") is simulated fascia. available as a kit complete. The P.E. Traveller has a 6 watts output, negative ground and incorporates an integrated circuit output stage, a Mullard IF f1.95 Per Pack. p & p £1.00. module LP1181 ceramic filter type, pre -aligned and Pack 7A may only be purchased assembled and a Bird pre -aligned push button tuning unit. at the same time as Pack 7. The P.E. Traveller fits easily in or under dashboards. NOTE: Constructor's pack 7A Complete with instructions. sold complete with radio kit f15.20 including p&p. C 323 EDGWARE ROAD, LONDON W2. For Personal Shoppers Only. 71"0"aSmat5 21 E HIGH STREET, ACTON W3 6NG. Mail Order Only. No Callers. Closed Thursday ACCESSORIES ARE Olin AvAltABII 10 NMI f76.00 /4011 NEW CUS101AIRS WHEN BultiNt OuR BARGAIN PACKS 100 WATT MONO Mullard DISCO AMP Brushed aluminum 12+12 fascia and rotary controls Size appros14" x 0" . 111.4" AMPLIFIER KIT AUDIO MODULES IN Flue venical slide controls, master volume, tape level. mrc level, deck level, PLUS INTER DECK FADER for perfect graduated change from record deck No. Ito An opportunity to build your own 12 watts per channel sreo amplifier No 2, or vice versa. Pre lade level control (PELT lets YOU hear next disc before with upto.theminute features To complete you pal soly screws BARGAIN PACKS lading it in VU meter monitors output level. Output 100 warns RMS 200 watts peak connecting wire and solder Features include din inputs diets for ceramic cartridge. microphone, tape or tuner Outputs-pe. speakers and CURRENT headphones By the press of a button it transforms into 24 wan mono EMI SPEAKER BARGAIN disco amplifier with twin deck miung The kit incorporat a Mulled CATALOGUE ,J^, Stereo pair 350 kitSystem consists of 1,1183 pre wiry module, plus 2 power amplifier assem I kits. Also 13" x 8'' minor woofer with rolled featured 4 slider level controls, rotary bass and treble c trols and 6 push PRICE sortoind3*," Goodman tweeter button switches Silver finish lascia panel with matching knot: Easy to AT OVER crossover components and circuit assemble teak simulate cabinet and ready made metal w rk For tonher diagram frequency response 20 Hz information instructsons we available price 50p Free to 20 KHz Power handling 15 watts RMS 20 watts max Size s 84"14" appros with kit Ei3.95 V7rti 8 ohm impedance NOTE for use with 4 m 8 ohms speakers p&p f2 55 PER PAE-t, SEEOUR PRICESs TWO WAY SPEAKER KIT To suit above amp Comprising 2 f18.25 PACK 1 2. 1P1173 I Ow RMS output power audio d111,111111i11,11, 8" approa Phillips base unit. and 2, 31/2" appros tweeters with per ster eo pan LP1182/2 Stereo pre amp for ceramic and 8.111011, 2 crossover capacitors 54.95 p&p 11 65 OUR PRICE f nn Available only to first time purchasers of the 12 + 12 kit p&p f I10 PACK 2 2 101173 lOw RMS output power audio amp modules BSR P200 50 WATT MONO Belt drive chassis turntable 1 LP1184/2 Stereo pre amp for magnetic. ceraminc and auxiliary f 25.50 inputs unit semi -automatic. cueing deviceP&P a 00 DISCO AMP illUS. OUR PRICE f 7.65 p&p f 115 Shure M75 6 Magnetic Cartridge to suit f30.60 ACCESSORIES Suitable mains power supply pans consisting of f7.95 mains transformer. bridge rectifier smoothing capacitor and set al rotary p&p f3.20 dtereo controls for treble bass Manual single pl Size appros 134" ri r 64" ,oiume and balance, f 3.00 plus p&p f 1 60 S auto 50 watts rms 100 watts peak output Big features include two disc oput Two Way Speaker Kit Comprising of two 8" x 5" approx 4 ohm return and cueing lever lined verlh Mete° both for ceramic cartridges. tape input and microphone input Level mixing bass and two 31/2" 15 ohm mid range tweeter with top cross -over capacitors ceramic canridge 2 speeds wan 45 Io eta controls tome with integral push.pull switches Independent bass and treble spindle adaptor -death, sodenfor home controls and master volume Pe:ssp',:;eoir f4 05 dtSCO use P&P OUR PRICEf 12.25 E2 75 PHILLIPS RECORD PLAYER DECK GC037 HiFi record player deck, belt drive complete with GP401 magnetic R C cartridge-LIMITED STOCK ter, cn rrl A. I .i.11.1 complete UNBEATABLE OFFER AT BUYER COLLECT ONLY -- 323 EDGWARE ROAD, LONDON W2 30 + 30 WATT STEREO AMPLIFIER Viscount IV unit in teak simulate cabinet Salver finish rotary controls and 21 E HIGH STREET, ACTON W3 6NG pushbunons with matching fascia red mains indicator and stero lack socket ACTONMail Order only. No callers BARGAIN OFFER Functions switch for mit magnetic and crystal pickups tape tuner and 31.111liary ALL PRICES INCLUDE VAT AT 15'U All items subject to sveitability. Price correct as Ariston pick-up arm Rear panel features fuse holder DIN speaker and input socket 30 * 30 watts 1 5.80 and subject to change without nottc manufactured in Japan. RMS 60 60 watts peak for use with 4 to 8 ohm speakers p Ivo fin All enquires Stamped Addressed Envelope. Sire 14kr"3" x 10" approx Complete with headshell. BUILT AND READY TO PLAY (JR, (3 301ePOLNUIAP NOTE Poisons under 16 years not served wrdrout parent's authonsation Listed price over (30 .00 . Personal Shoppers EDGWARE ROAD LONDON W2 Tel 01.723 84329 30am 5 30pmClosed all day ThursdayACTON. Mail Order only No callers pOoos OISPALCMCD TO MAINLAND AND a ICELAND My ETI JULY 1980 83 STATE VARIABLE 80-7 VOLTAGE CONTROLLED STATE VARIABLE FILTER FILTER 4 4 c 6 4 3 7 3 7 3 Choose one of seven filter 8 2 82 9 9 1 9 0 10 0 10 0 10 responses with this voltage OCTAVES FINE RESONANCE HP2 N f3P4 4 5 6 controlled state variable filter LP2 LP4 3 7 3 BP2 410, HP42 82 8 9 design by R.C. Blakey foryour 1 401119 0 10 0 0 ". FUNCTION SIGNAL 1 CONTROL 7 Project 80 modular synthesiser. The Voltage Controlled State Variable Filter has low Solid State Micro Technology for Music, namely, the pass, high pass, band pass and notch filtering cap- SSM2040. This device contains four closely matched abilities. The first three responses are available as transconductanceamplifiersandanexponential both two pole (12 dB/octave) and four pole (24 dB/oc- generator whichis common to the four cells.For tave) filters. Manual and external control of resonance is resonance control the relatively new LM13600, dual included. transconductance amplifier, is used in the feedback of the two stages of state variable filters. Both manual and external voltage control of resonance is provided and Design Features while these controls are additive the maximum useful The state variable filter using three operational range is our standard 0 to 10 volts into 100k. amplifiers, as shown in Fig.1, is probably familiar to most Seven filter responses are available, one at a time, readers. via a selector switch - low pass (12 and 24 dB/octave); high pass (12 and 24 dB/octave); band pass (2nd and 4th HIGH PASS A--1 orders); and notch. The low pass and high pass outputs are 180° out of phase and so combining these outputs results in a notch. A notch filter is of limited use in syn- thesis since the ear only responds to frequencies present and not to frequencies which are absent. The latter may LOW PASS, A-.1 sound rather obvious but since the notch filter allows most frequencies to pass the ear cannot detect the dif- BAND PASS ference between the original and filtered signals, except in some exceptional circumstances or unless the notch is fairly wide. The filter has three signal inputs and the combined signal should not exceed 10 volts peak to rleak. An at- Fig.1. Circuit diagram of a state variable filter using three op amps. tenuating potentiometer has been provided on one of the inputs and if mixing of signals is required then external A simple way to convert this into a voltage controlled attenuating controls can be used. The filter has approxi- filter istointerposeoperationaltransconductance mately unity gain at maximum resonance feedback. amplifiers (eg CA3080) prior to the two integrators Frequency response control is obtained using the ex- around IC2 and IC3. Voltage control of Q (or resonance) ponential converter within the SSM2040 and an at- can also be obtained by using an OTA in the feedback to tenuating network, with adjustment, allows the 1 V/oc- the non -inverting input of IC1. This is the basis of the pre- tave characteristic to be obtained.Initial frequency sent design. Such a filter gives 12 dB/octave low and high (zero control voltage) is set to approximately 20 Hz and pass responses and second order band pass response. By the filter has a 1,000:1 control range. Control Input 1is placing two such filters in series it is possible to increase used for keyboard input; Control Input 2 has an at- the roll -off characteristics by a factor of two. In practice, tenuating potentiometer for use in conjunction with an however,thisisoftendifficult due to component envelope shaper, etc; a Coarse control provides manual mismatching whichresultsinunevenroll -off sweep over 10 octaves and a Fine control is included for characteristics. The problem has been minimised in this more accurate initial setting and has an adjustment design by using a customised integrated circuit from range of one octave. Temperature stability should not be 84 ETI JULY 1980 PROJECT 111=111.1.1.11 but this should not pose any problems if reference is made to both the circuit diagram and the PCB layout. Setting Up And Calibration First adjust the module to achieve the seven filter re- sponses. These can be readily observed on an oscillo- loscope by using the VCLFO and VCO as a sweep fre- quency generator, as described for the 80-6 filters. There are, however, only two adjustmenst to make in order to ensure that the seven responses are present (assuming no wiring errors) and these can be made by ear with the aid of an amplifier, as shown below.- CONTROL SAWTOOTH INPUT 1 SINE INPUT VCLFO VCO FILTER 80-3 80-7 AMPLIFIER Fig.2. The seven filter responses can be inspected with the circuit shown above. Set Coarse frequency controls on VCLFO and filter 80-7 to mid position and to zero on the VCO. With the edge connections of the filter facing you and the components uppermost set the wipers of both PR1 and PR2 to about the 9 o'clock position. Put selector switch on BP2 output and slowly turn PR1 anti -clockwise. Initially there may Fig.2. The voltage controlled state variable filter can be built into be no output but then a low pass output will be heard. this Teko Alba case (see Buylines) as a 'stand alone' project. Further rotation of PR1 will result in a fairly abrupt change from low pass to band pass and this is audibly obvious. PR1 should be left at this setting. Now switch to LP4 output and turn PR2 slowly clockwise.Initially a problem under normal circumstances.Ifrequired, nothing will be heard and then a low pass response. PR2 however, R47 may be replaced by a Q81, 1k0, 1% temperature compensating resistor. V.C.STATE VARIABLE FILTER 5 40., 6 4 5 6 Construction If you wish to build all of the 2'lri 8 2 The tirst point to note is that the SSM2040 outputs tiny1./ Project 80 modules and install (OUT, CAPACITOR and IN) are not short circuit pro- d them in a single case with key- board, mount the PCB on this tected and shorting any of these to either supply will front panel. At the end of the generally blow the circuit, although connections to series you'll have a matching ground can be tolerated for several seconds. Some addi- 3 set. tional resistors have been used to provide additional 8 2 Or, safeguard in the latter circumstances. Take particular I care on both the orientation of this ICand when any pro- bes are connected to components on the PCB, for SIC OT:.; 4 Sr, HP2 0'4 whatever reason. 7 3 41* L P2 LP4 Identify and solder the seven wire links before in- e 8 8P2 HP stallingcomponents.Thecapacitorsaroundthe (111114 4 SSM2040 will accept both preformed (as illustrated)and. 9 normal polystyrene capacitors. When all components RESONANCE6 FUNC T ION have been installed, the two holes remaining around IC1 are forinstallinga Q81 temperature compensating resistor, when required. The manual resonance control (RV2) may be wired via the jack socket used for the exter- nal resonance control such that the former is disabled when external control is in use. The manual and external lio411O controls may also be wired up independently but no in- crease in gain will be achievedwhen their combined 11) voltages exceeds the equivalent of about 10 volts into C 2 52 Out 100k, eg manual control half way and five volts external input.In fact the resonance will begin to decrease RES. 53 somewhere above 10 volts. The most complicated task is wiring up the switch 80-7 ETI JULY 1980 85 F110 10k 011 RVI 22k LP2 100k Ion R51 10k SIGNAL R12 10k 02 100k C3 R13 22P SIGNAL 3 22k Hp, 03 R4 100k 10k 827 15k RS R7 R14 C7 104 10k 10k 22o IC2 815 RI 10k k0 5 R6 Ca RR CS N 2008 1n0 200 1n° 30k 818 15V 104 OUTPUT R23 15k NOTE 101 IS SSM2040 IC2 IS TL0131CP 024 15k LP4 ICS IS LA/13600 30 ICONS ARE TLOSICP Ok R52 R25 24k -"\AAA-- 220 NAN --O1.1P4 31 010 PR3 15k 10k R19 021 R40 10k 10k 300k 13 Ca -15V 2 CONTROL 2 1k0 14 14 10.12 R20 9 R22 CONTROL 1 033 2000 C10 nO 2008 1n0 R32 Ski RV3 R46 TO PINT 30k 100k OF ClI In -15V EXTERNAL RESONANCE CONTROL RAT 140 11V4 15V 100k 15V 0 I el COARSE FRECONill 470n TO PINS OV ISIS OF IC3 11115 1004 C2 lin FINE 0 T "°" FREOUENCV CONTROL Fig.2. Circuit diagram of the state variable filter. HOW IT WORKS The SSM2040, VCF produced by Solid State Micro Technology pass outputs which are 180° out of phase. These four outputs are for Music, contains four independent filter sections which may connected to the rotary switch, SW1a and the signal restored to be interconnected to provide a wide variety of filter responses. its original level by R49, R50 and IC5b. The signals are AC coupl- Each section contains a transconductance amplifier followed by ed into IC5b to remove any DC offsets. a buffer and by using two of these sections with an external op amp a state variable filter may be realised as shown below. The low pass, high pass and band pass outputs from the first stage are also separately connected to rotary switch, SW1b and fed into the second stage formed around IC3b, IC4a, IC1c and IC1d. The four pole outputs derived in this section return to switch SW1a and are available via IC5b, as before. Resonance control is provided by an LM13600 (IC3), dual transconductance amplifier, interposed between the band pass output and the non -inverting input of the filters external op amps (1C2 and IC4a). The amount of feedback is controlled by the cur- rent developed across R39 and this has been commoned for both halves of the LM13600. Manual control is obtained via RV2 and R36 into IC4b and external voltage control via R34 into the same input summing node. The control voltage should be limited to an Fig.3.Using the sections of the SSM 2040 and an op amp equivalent of 10 V into 100k. to form a state variable filter. Frequency control is common to all four amplifiers in the The signal levels into the gain cells should be limited to SSM2040 and best results for a 1,000 to 1 sweep in the range 20 2mV RMS and since R2 should be 200 R for optimum control Hz to 20 kHz is obtained with +90 V at pin 7. Resistor R40 con- rejection then R1 is 10k with a 1 V signal at the op amp output. nected to - 15 V provides approximately +90 mV and a lower The equivalent input noise for the SSM2040 is 0.5 uV RMS at 20 frequency limit of about 20 Hz. A 0 to + 10 V control voltage in- Hz to 20 kHz so a signal to noise ratio of about 90 dB is achieved. to Control Inputs 1 or 2 will then allow frequency adjustment In the first state variable filter section around lC3a, IC2, IC la and over a range of ten octaves. Manual adjustment over a ten octave IC1b a 10 V signal into R1, 2 or 3 is reduced by IC2 and R4 to range is provided by the Coarse Control (RV4 into R43) and Fine produce the 1 V into attenuating resistor network R5, 6. The Control over a range of one octave by RV5 into R44. Precise ad- two pole low pass, high pass and band pass filter responses are justment of the 1 V per octave response is achieved by adjusting derived and a notch produced by combining the low and high the gain of IC5a using PR3. 86 ETI JULY 1980 PROJECT: State Variable Filter PARTS LIST Resistors l/4 W, 5%carbon film except where stated 81,2,3,34,35,37 100k LP4,SW1a W6_ R4,5,7,10,12,14, 15,16,18,19,21, BP4,SVVla WE 48,51,52 10k HP4. SW1a W7 R6,8,20,22 200R R9,11,13 22k R17,50 1k0 R23,24,27,31 15k 2nd STAGE INPUT FOR SW1b POLE R25 24k It 13 1- R26,28,30,32,39 30k R29,33 5k1 EXT. RESONANCE R36 150k CONTROL R38 27k MAN. RESONANCE 300k, 1% metal film CONTROL R40 R41,42 100k, 1% metal film R43 150k, 1% metal film NOTCH, SW1a W4 R44 1M5 LP2.SW1a "/2 R45 91k, 1% metal film TO SW1b, W6 T R46 56k, 1% metal film HP2,SW1a W3 R47 1k0, 1% metal film R49 200k TO SW1b, W7 Potentiometers RV1,2,3,4,5 100k linear PR1 2 1k0 carbon SIGNAL 3 -PR3 20k cermet multiturn SIGNAL 2 832 SIGNAL 1 Capacitors +15V ri- C1,2 470n polyester BP2.SVV1a VV1 C3,7,8 22p polystyrene C4,5,9,10 1n0 polystyrene TO SW1b W5 1-LINK C6 220n polyester OUTPUT FROM SW1a POLE Semiconductors IC1 SSM 2040 cs z IC2 TL081CP, or equivalent ov < 2 IC3 LM13600 FREQUENCY o IC4,5 TL082CP, or equivalent CONTROL 1 should be left at the setting where the low pass output proach is to set all VCF controls to zero and apply about commences. The selector switch can then be turned 4 V to Control Input 1 and measure the voltage at the through its seven dutputs to check that the appropriate junction of R46 and R47, using a high input impedance response is present and these can be clearly identified by voltmeter. Increase the control voltage by exactly 1 V ear. If an oscilloscope is available then switching to BP2, and then adjust PR3 to obtain an 18.0 mV change at the LP4 and HP4 outputs and making minor adjustments to junction of R46 and R47. Again repeat the procedure un- both PR1 and PR2 may result in some improvement to til an 18.0 mV change is obtained for a 1.000 V change in the filter responses. control voltage. The final step is to calibrate the filter for 1 V/octave frequency control. The 80-7 filter will not oscillate at maximum resonance feedback and so the best approach is to observe the maximum signal amplitude usingan BUYLINES oscilloscope. Connect the sinewave output froma VCO to Signal Input 2. Connect the LP4 output to an oscillo- An 80-7 State Variable Filter module kit (PCB plus components) is scope, set VCO frequency to about 250 Hz and adjust available for the inclusive price of £20.10 from Digisound Ltd, 13 RV4 (Coarse Control) and RV5 (Fine Control) to obtain The Brooklands, Wrea Green, Preston, Lancs PR4 2NQ. maximum signal amplitude. Increase voltage on Control The modules are cased in Teko Alba A23G cases (order code TEK A23G), available from West Hyde Developments Ltd, Unit 9, Inputs 1 of both VCO and VCF by exactly 1 V and adjust Park Street Industrial Estate, Aylesbury, Bucks HP20 1ET at £4.43 PR3 until maximum amplitude is restored. Repeat the each all inclusive. abovestepsuntilcalibration is achieved.Ifan oscilloscopeisnot available then an alternative ap- ETI JULY 1980 87 ENVELOPE SHAPER Tamper with your time constants. This Project 80 design by R.C. Blakey gives full control of Attack, Decay, Sustain and Release. The envelope generator is based on the SSM2050, a voltage controlled transient generator produced by Solid State Micro Technology. Using this IC all that is necessary to vary the time constants for the At- tack (A), Initial Decay (D) and Final Decay or Release (R) is a voltage applied to the appropriate pin via a scaling resistor. A minimum range of 2 mS to 20 S is available for each of the three timing functions. The voltage response is exponential which means that the most useful time range utilises the highest proportion of the associated control potentiometer. The attack output is nominally 0 to 10 V and the Sustain level (5) is simply a voltage ap- plied to Pin 12. It has separate gate and trigger inputs whereby a combined gate and trigger pulse will initiate a full ADSR response; a trigger applied after the first one and while the gate pulseisstill present will restart the attack response and a gate pulse on its own will generate an AD contour. When the gate pulse is released the final decay commences, as is usual with ADSR and AD envelope shapers. ID ID .10V AT FD FD AT Vsus AT FD Vout OV ID GATE TRIGGER Fig.1. Wave forms associated with envelope processing. The time constants may be trimmed so that any number of ADSR's can be adjusted to exactly the same scale. Also an adjustment to ensure that the sustain voltage accurately matches the peak attack voltage is provided. The output buffer in the SSM2040 is adequate for most practical purposes but to retain our 'plug in anything to anywhere' philosophy an external buffer has been added. Other features included are external initi- ation of the ADSR or AD contours, for example, from a that when only single pulses are available, eg, manual manual push button, as well as provision to use gate and gating, then both the ADSR (SW1 closed) and AD (SW1 trigger pulses derived from TTL logic. open) responses can be obtained. The manual gating can be added by connecting a push to make switch between the PCB connections marked 'OUTPUT FOR MANUAL Construction GATE' and 'MANUAL GATE'. The push button may be The PCB is designed to take two envelope generators panel mounted but the preferred approach is to take the and as usual will fit either a panel or the TEKA ALBA A23G former connection to a jack socket and to use an exter- case. If the latter is used then there is only sufficient nal hand, or foot, switch connected to two jack plugs. panelspacetosensiblyinstall a singleenvelope These jack plugs go to the Gate (G) input and the Manual generator. input (from R11). The option and type of switch is left to Construction is very straightforward and the only the constructor. points to note are the single"wire link and the opposed Resistors R12, R13 and R14 are not part of the basic orientation of the SSM2050 and the 741 buffer. kit but are to be installed by constructors who are using An on -off switch, SW1, is connected across the in- TTL logic to derive gate and trigger pulses. Also in this puts marked 'TRIGGER (CMOS)' and 'GATE (CMOS)' so case the switch. SW1, is connected across the PCB con - 88 ETI JULY 1980 PROJECT +15V0 RV11.4 SUSTAIN 100k I LEVEL S lin PR1 R1 22k 33k hiR2 100k +15V 0 -15V +15V RV2 PR2 FINAL 100k DECAY R 100k lin --15V 0 +15V R6 R3 R4 R5 0 0 330k 330k 330k R V3 +15V t+C1 INITIAL 10u DECAY D 100k lin 14 0 +15V OV 25V -15V + C2 NC 0-,2 13 0 NC 10u +15V 0 -15V T 25V R7 0 0 12 RV4 ATTACK A 100k C4 R8 lin ICI 100n -15V 0 R9 1k0 C3 /77/7 I 10n TRIGGER (CMOS) 0 TRIGGER (TTL) 0 GATE (CMOS) 0 0 NC R10 MANUAL GATE 0 1k0 CE-43 R14. 0 15V SW1 (SEE TEXT) 2k2 GATE (TTL) 0 0 +15V R11 15k R15' OUTPUT FOR ci-AAAr-- 4-15V 8k2 MANUAL GATE NOTE: IC1 IS SSM2050 R12 IC2 IS 741 15k FOR TTL TRIGGER AND GATE INPUTS ONLY OUTPUT Fig.2. Circuit diagram of the Envelope Shaper. nections marked 'TRIGGER(TTL)' and 'GATE(TTL)' to HOW IT WORKS provide the same function as before. For manual gating with TTL a push to break switch should be connected The SSM2050 Voltage Controlled Transient Generator contains a between 'GATE(TTL)' and OV, since the gate and trigger voltage controlled resistor to generate the nominally exponential pulses are held high by the additional resistors. slopes and various logic devices to define the states. An attack flip-flop (AFIF) is set by the trigger pulse and reset by either NOT GATE or the attack comparator determining that the output has reached +10 V. Thus ATTACK = GATE and AFIF; INITIAL Setting Up And Calibration DECAY = GATE and NOT AFIF; FINAL DECAY = NOT GATE. Provide a means of manually gating the envelope Each state is characterised by a nominally exponential approach to a characteristic voltage; these being + 13 V, sustain voltage generator as described in the previous section and the and 0 V for attack, initial decay and final decay respectively. switch may be constructed from two strips of metal, if The input stages of the SSM2050 logic inputs have a lateral necessary. Connect the output to a voltmeter set to a DC PNP structure which protects them from excess voltages. Their range of 15V and turn Attack control (RV4) to about 3 sensitivity is 750 uA or 1V5 max., these being the minimum cur- o'clock position and all other external controls to zero. rent and voltage required to trigger the SSM2050. For 5 V, 10 V and 15 V CMOS gate and trigger inputs these requirements are Put SW1 in the ADSR position (gate and trigger common- met using 1k, 10k and 15k resistors respectively to these inputs. ed), turn PR1 fully anti -clockwise and PR2 about mid The attack, initial decay and final decay inputs have a position. Apply power to the module, depress the nominal impedance of 3k1 and a time constant sensitivity of 18 manual button and keep held down while observing the mV/octave with a 100n timing capacitor (C4). An increasing positive voltage increases the time constant. Thus R6, 7 and 8, voltmeter. The voltage should steadily rise and will pro- connected to +15 V via the rotary controls RV2, 3 and 4, will bably take between 5 and 20 seconds to reach about have nominal values of about 300k to achieve a five decade tim- 10V. Since the module is not calibrated the time taken ing range from 2 mS to 20 S. The input impedance, however, may be outside of the range stated. The important point varies by up to + 25% between devices. Fortunately the im- pedance may be measured with a high input impedance ohm- is that the voltage increases to a maximum of about 10V meter as the resistance between pins 1 and 7 and so the ap- and then drops sharply to zero. If this response is observ- propriate scaling resistor may be selected by multiplying this ed then set Sustain control (RV1) to mid position and resistance by 100 and adding 10k. The nearest E24 resistor is RV2, 3 and 4 to about the 3 o'clock position.(a little less chosen and more precise adjustment of timing is achieved by in- jecting a small offset voltage via PR2 and R3, 4 and 5. The attack if the time to reach 10V was greater than 10 seconds in voltage may vary between 10 and 11 volts and PR1, R1 and R2 the previous step or a little more if the time was less than provide a means of matching the maximum sustain voltage to the 5 seconds). Press button and hold down as before. The peak attack voltage. The sustain level can then be varied from 0 voltage should now rise to about 10V and then decay at to 100% of attack voltage using RV1. As an additional safeguard the output of the SSM2050 has the same rate to a voltage of approximately 5V and re- been buffered by IC2 configured as a voltage follower. main steady. On releasing the button there will be a final decay to about OV. Finally, open switch SW1 to check ETI JULY 1980 89 PROJECT: Envelope Shaper -1- -r PARTS LIST Resistors 1/4W, 5% Carbon film R1 33k -ce R2 100k R3,4,5 330k R6,7,8 see text R9,10,11 1k0 SUSTAIN, RV1'N R11 15k FINAL DECAY, RV2W INITIAL DECAY,RV3W Potentiometers ATTACK, RV4W RV1,2,3,4 100k linear PR1 22k carbon TRIGGER (CMOS) PR2 100k carbon TRIGGER (TTL) GATE ICMOS) Capacitors C1,2 10u 25V electrolytic MANUAL GATE C3 10n polyester GATE (TTL) C4 100n polyester OUTPUT ov Semiconductors R15 IC1 SSM2050 IC2 LM741CN, or equivalent Miscellaneous SW1 Sub Min SPST (or SPOT) switch SUSTAIN, RV1W FINAL DECAY, RV2W INITIAL DECAY, RV3W R7 1"' ATTACK, RV4W TRIGGER (CMOS) TRIGGER (TTL) --f R 10 I- GATE (CMOS) LINK MANUAL GATE =:e GATE (TTL) OUTPUT -15V 15V +15V + 1 5V OUTPUT FOR MANUAL GATE Fig.3. Component overlay. n0+ ov the AD response and repeat the last step. This time the The final step is to adjust the time constants and this voltage should rise to about 5V and maintain this value calibration is only required for the Attack time control until the button is released which will initiate the decay (RV4). The module should be in the ADSR mode (SW1 to about zero. Note that in the AD mode the Initial closed) and all other control pots set to zero.If an Decay control (RV3) determines the attack time and the oscilloscope with a triggered sweep is available then the Sustain level controls the amplitude of the AD contour. gate and the oscilloscope can be simultaneously trig- The above demonstrates that all functions are opera- gered and PR2 adjusted to give an attack time of 2 mS tional. when RV4 is at zero. An alternative method is to time the The next step is to adjust the sustain voltage to attack period, for example, by observing a voltmeter match the peak attack voltage. Close SW1; set RV4 to connected to the output and measuring theitime between about 3 o'clock; RV1 fully clockwise; RV2 and RV3 to pressing the manual push button and the voltage drop- the zero. Depress the manual button, observe the volt- ping sharply. With the latter method adjust RV4 so that meter and note whether there is a discernible drop in there is 10V0 at its wiper, trigger the module and adjust voltage after the attack has reached its peak. If so, turn PR2 until the time taken is 9 S (slightly more than less). PR1 clockwise and repeat the last step. Repeat until When this time is obtained turn RV4 to zero and check peak attack voltage and sustain level are matched. The that a fast response time is obtained. adjustment to PR1 must be made in small increments so as to avoid having a higher sustain voltage than the attack voltage, otherwise malfunction of the SSM,2050 BUYLINES can occur. Itis therefore better to err on the safe side and wait until the envelope shaper is connected to the A single 80-8 module with PCB and all components shown on the circuit diagram for CMOS inputs is available from Digisound VCA at which time any mismatch between the two volt- Limited for £9.83 and a dual unit for £17.02, both inclusive of ages can be checked by ear and a minor adjustment postage and VAT. made to PR1 to correct it, if necessary. ET! 90 ETI JULY 1980 Quantum Electronics UNBEATABLE PERFORNANCE, UNBEATABLEPRICES FROM £162.21 * NEW SPEAKER KITS * Have you wondered why the existing sources of speaker kits offer a bewildering choice of systems, particularly combinations of 200mm bass unit and tweeter? Don't they know which ones are best? If so, why bother with the rest! Well we have sorted out these super kits so you can order in confidence, knowing you get our full endorsement of their performance and value. The kits incorporate profesionally finished front baffles with the drive units already mounted so all the fiddly work is done for you. All that is left to do is to make a simple box. Crossover networks, foam and terminals are also included. Have you noticed how the top end audio equipment has risen in price out of reach of many people? Even some kits are now very expensive. Well, while others make inflated claims about cost-effective designs Quantum is the only one to deliver the goods. At £215.66 our 102 / 202 pre -power combination is the lowest cost British amplifier to cater for moving -coils and it gives a very generous 45W per channel.Itis also available in kit form for a mere £162.21! Our 102/204 at £237.81 is the lowest cost 110W British amplifier or in kit form it is £184.35. So how has this come about? We have not scrimped on the electronics. For instance, the pre -amplifier, though sparse in controls, uses no less than six I.C.s and 22 transistors ina unique and elegant circuit configuration. We have not lost out on performance. The overall t.h.d. of the pre -/power amplifier is below .01% at 1kHz, typically below .005% at 10W with a slew rate of 35V / uS. The main reason our prices are so low is that we have taken steps in the design to produce a low cost method of assembly, and we have then priced them accordingly. This is exemplified in our 102 pre -amplifier, which, because of its single board construction, we can offer for £80.41 ready built or in a "no soldering" 20 minute easy build kit for £70.95. If this was in a more conventional package of module, loose pots, sockets, etc. we would have 1 2 to charge more for no improvement in performance, just the dubious privilege of hours of fiddly wiring! The 102, shown above with a 202, is all that virtually anyone requires, catering for auxiliary, 2 or 3 head tape and moving coil or magnetic cartridge. The sensitivity and load for the disc input is specified by a small, cheap (£3.30) System 1. Small bookshelf design using Son Audax 200mm bass unit and plug-in card, which makes it idealif you might upgrade to moving coil from 25mm dome tweeter, giving very good results from a small enclosure. magnetic - just buy a new card or change the existing components. Cards are System 2. Using similar drive units to system 1this is a larger reflex design available off the shelf to suit the majority of popular cartridges but full matching intended to be used on a stand. We can enthusiastically recommend this as the information is supplied with each pre -amplifier. When used with our 202 or best 2 -unit kit we have heard to date with a smooth and extended bass response 204, all that is required is a special connecting lead, called AC1 at £3.98. For and excellent stereo image. use with other power amplifiers there are mains power supplies both ready built System 3. A 3 -way I.B. system using a Seas 250mm bass unit, Seas 120mm and in kit form. These are described fully in our detailed information, as are our midrange and Son Audax 25mm dome tweeter. A floor standing design cleverly moving coil head amplifier modules and kits. incorporating a stand at the bottom of the enclosure. Order now for August Our 205s are the ultimate in low cost super-fi. Designed to drive any delivery. loudspeaker this is a mono power amp to be used in pairs for stereo, giving System 4. The most sophisticated, most expensive and undeniably the best 145W r.m.s. into a 8 ohms, 260W r.m.s. into 3 ohms, with a transient power of speaker kit on the market using a 250mm Volt bass unit with a 250mm Volt ABR 600VA into 2 ohms. A complete system, including pre -amplifier, ready built is for the bass, a very specially treated Peerless mid range unit and a Son Audax £385 plus leads or in kit form for £277 plus leads, the price you might pay for a. 25mm dome tweeter. The Rolls Royce of speaker kits comes with the active drive low power system. The full range is described in our information. units mounted on. the front baffle and the ABR on the rear baffle. A floor Our power amplifier kits are supplied with ready built and tested printed mounting design incorporating a stand as above. Excellent bass response and circuit boards and are complete down to the last washer. They require only smooth untiring mid band and treble are the result of countless hours of simple assembly and point to point wiring following the detailed instructions and dedicated development by one of the country's leading designers. Capable of wiring diagrams. very high sound levels when used with a good amplifier, such as our 205s. Pre -Amplifier, built 102, £80.41; kit £70.95. Lead, AC1, £3.98. 45W, 202 Orders accepted now for August delivery. We will also be retailing selected drive units at competitive prices. Please ask built, £131.27; P2 kit £87.28. 110W, 204 built. £153.42; P4 kit £109.42. for details. MODULES, SUPPLIES System 1 £69.00. System 2 £89.00. System 3 £159.00 System 4 £359.00 The module used in the 102 pre -amplifier is available separately as the C2. at Son Audax 200mm bass, 20825J4 £13.50. 25mm tweeter, HD100D25 £51.75, and is complete including all pots, switches and sockets requiring only £9.00. a'_ 25V supply a kit for which the CS Iis £12.13. We have the widest range of power amplifier modules, from 45 to 260W r.m.s. in the popular L bracket mounting up to1 70W "module rating" and in medium and high dissipation formats using large separate heatsinks. These achieve the highest standard of reproduction but can be used in stage or P.A. applications. We also have power supplies for use with these modules, all using toroidal transformers. Our largest is for two 260W modules, using a massive 500VA transformer. Full details in our information. We have too many items to describe in such a small space but here are a few examples: QE1 708 - L bracket mounting giving 1 50W r.m.s. / 8 ohms on our MS3 supply £31.96 M1508 - As QE1708 but with the power transistors mounted on a 76mm heatsink £35.79 MS3 - Toroidal power supply for 1 or 2 QE 1 708s or M 1 508s £26.28 QE1708 M1508 M2603 - Giving 150W/8 ohms, 260W r.m.s. /3 ohms this uses four 1 50W power transistors mounted on two 76mm heatsinks £50.28 MS5 - Toroidal power supply for 1 or 2 MS2603 £39.68 8 ALBION ST., LEICESTER Write or phone for our full information. All prices include VAT and carriage. Export is no problem - all equipment can be 10% OFF! wired for 1 10V - send for quote by return. YES! IF YOU SEND AN ORDER TO REACH US BY 14 Enquiries are invited from retailers and trade. Excellent discounts available. JULY ENCLOSING THIS AD. YOU CAN DEDUCT 10% If you don't see what you want, ask. Tel: (0533) 546198 FROM ALL OUR NORMAL PRICES! BEAT THAT! ETI JULY 1980 91 ETIPRINTS are a fast new aid for pro- ETIPRINTS are made from our original ducing high quality printed circuit artwork ensuring a neat and accurate boards. Each ETIPRINTS sheet con- board. We thought ETIPRINTS were tains a set of etch resistant rub down such a good idea that we have transfers of the printed circuit board patented the system (patent numbers designs for several of our projects. 1445171 and 1445172). PARTS LIST Shown below is the listing for Earlier sheets are available, the last year's ETIPRINTS. ring Tim Salmon for details. ETI 80 - VCO Feb 80 0326 038A Long Period Dec 79 049A Sep 79 Timer and VCLFO 033 Fuel Level Monitor, Rain Alarm Alarm, screen controller Dynamic Noise Reducer Touch Switch 040BETI 80 - PSU Feb 80 Flash Trigger Tuning Fork Pseudo Random Filter 040A Noise Gen Coin Toss 0428Touch Dimmer, Apr 80 Battery Charger Mar 80 03813 Hum Filter Dec 79 041AETI Audiophile RC Guardian 'Dice ETI VCA (Top,Bottom)1Et2 Logic Probe Signal Trace ETI HC 038C Function Dec 79 E lectromyogram 043 IR60 preamp, May 80 Generator 041B VCM Mar 80 Receiver, PSU, Heater Controller Serva Tester, Jan 80 VU-PPM 039 Buffer Apr 80 Moving Coil Preamp 042A 300W Amp Module Process Controller 033 Fuel Level Monitor, Sep 79 044AIR60 Function June 80 039A Hum Filter Dec 79 Alarm, Screen Controller Board (Top 8. underside) Logic Probe Dynamic Noise Reducer Control Circuit, 042B Dimmer, Apr 80 Line Transmitter, 039B Long Period Timer Dec 79 Battery Charger, Tape Response Meter Rain Alarm RC Guardian Ohmmeter Touch Switch (Top, Bottom) 1 & 2 Flash Trigger Pseudo Random 043 IR60 Preamps, May 80 044BFM receiver June 80 Noise Gen Receiver, PSU, PSU Er Monitor Amp Servo Tester Drum Synth 039C Function Generator Dec 79 VU-PPM (function board) NOW IT WORKS Lay down the ET/PR/NT and rub over with a soft pencil until the pattern is transferred to the board. Peel off the backing sheet carefully making sure that the resist has transferred. If you've been a bit careless there's even a 'repair kit' on the sheet to correct any breaks! BUY LINES ORDER TODAY Send a cheque or P 0 (navable to ETI Magazine) to ETI PRINT, ETI MAGAZINE 145 Charing Cross Road, London WC2H OEE 95 pINC P & P 92 ETI JULY 1980 SUPERIOR QUALITY AND RELIABILITY SEIKO CASIO'S NEW EXECUTIVE NEW 11 -NOTE MELODY PRICES SLASHED! WATCH MAKER 79CS-51B ALARM CHRONOGRAPH CASIO ML -82 TSI Alarm Chronograph Full month calendar, tone control, hourly chimes Clock. calendar, musical alarm, hourly chimes. 1/10 second With countdown alarm. Hours, stopwatch to 24 minutes, seconds. alpha day and hours: net, lap and 1st date on upper display; and day, date. & 2nd place. month, alarm and hourly chimes Calculator with '44mG 6 Countdown alarm (upper display) musical keys, full Stopwatch from 1 /100 sec to 12 memory, %, square 111:013 59 hours: net, lap, and 1st and 2nd 3t1 roots. 9/32 a 21/2 x place times. Stainless steel. Glass. I el r n 4Vii inches. Ll .3 USu ONE YEAR BATTERIES Only £44.95 (RRP f22 95) £19.95 TS7 Alarm Chronograph NEW METRIC CONVERTER/ 100M Water Resistant. Suitable for CALCULATOR swimming, water skiing etc. Hours, Hours, minutes, seconds, am /pm and date. Calendar minutes, seconds, day, date and display: Day, date, month and year. Monthly calendar from month. Programmable weekly alarm. CASIO MC -34 CARD Interval alarm timer up to 16 hours. the year 1901 to 2099. 1/10 sec. stopwatch to 1 2hrs. Net, Hourly chimes. Stopwatch, 1/100 lap,1st & 2nd 24 -hour alarm with 10 step tone control. Hourly chimes, backlight, lithium battery. Stainless steel second to 20 minutes, then seconds use 8.6mm thick. Mineral glass, water resistant. (RRP to 12 hours. Upper display - lap 8 times. Lower display - Total time. `44351E39.95 I CASIO El CI 0 el 163 ONLY £64.95 OUR BEST-SELLING WATCH tp tip et El CI CASIO C-80 CALCULATOR go lig II la C3 TS5 World Time/Alarm WATCH cro as co ©O us go Two Alarms, local and world time (Finger -touch keyboard). (dual tones). Hourly chimes. Nor- Hours, minutes, seconds. 34 conversion functions, 17 metric, 17 reversible. Dis- mally displays hours, minutes am/pm, day. Day. date, tances, weights, areas, volumes and temperatures.Calcula- seconds, day; or optionally hours month, auto calendar tor with GT memory, %, square roots, 1,100 hours batteries, minutes, day, date, month. World pre-programmed to 2009. 5/32 x 31/4 x 21/4 ins time mode displays an atlas with each Professional 24 -hour 8:583u of the 19 time zones highlighted stopwatch: net, lap, 1st & when selected. Date and summer 2nd place to 1/100 sec. (E13 951£11.95 time functions. Dual time. (24 -hour). &Alb Nightlight, 8 digit Casio's guarantee is only valid if goods calculator. are purchased from an authorised GP *ID ' Water resistant.Gloss. Stainless £59.95 resin case/strap dealer, who WON'T advertise lower 44.9mmx35 800 2mm prices than ours. Nevertheless we Gold Plated £84.95 promise to BEAT (sensible) lower ONLY £24.95 prices IF the advertisers have stocks. Hundreds sold, TS4 Calculator Alarm Send for our FREE LEAFLET "The Hours. minutes, seconds, day, and whole truth about digital watches." day, date, month, am r prn. Alarm (2 83QS-41B ALARM tones). hourly chimes. 8 digit calculator with constants, delta %. CHRONOGRAPH OUR BEST SELLING Water resistant. 2 year battery with hatch. Approx. 9mm thick + 0.5mm S/S encased. Mineral glass CALCULATOR for keys. Water resistant.3YEAR BATTERY. Hours. minutes, seconds, date, am /pm. or FX-8100 hours, minutes, alpha day, date 11ERNE=IMMI661121111 1 YEAR BATTERIES Stainless £59.95 *am /pm, 24 -hour alarm. hourly Hours, minutes, seconds, chimes. Stopwatch from 1-10 am/pm. day. Calendar Gold Plated second to 12 hours; net, lap pre-programmed to year 1999 and 1st and 2nd place. 24 -hour alarm. Alarm timer, £84.95 Nightlight. interval timer, or 1/100 second =I= stopwatch: net, lap, 1st and TS2 Alarm Chronograph ONLY £24.95 2nd, place. Fractions. %, cube roots, 5 levels parentheses, hyperbolics, standard Comprehensive display of hours, F-80.. As above but with black resin case/strap with S / S deviations, co-ordinates, minutes, seconds, day, date and back and front trim. conversions. month. 24 hour alarm and X to Y. X to M hourly chimes. Stopwatch from £19.95 x 2 1/4x5Ye" (RRP 1727 95) 1 /100 second to 20 minutes, then seconds to 20 hours. Upper r. NOW AVAILABLE GOLD PLATED ONLY £24.95 12'S display -laptimes.Lower ie 00S9 display -total time. S /Steel HUNDREDS SOLD! encased-8mm thick plus front 83 QGS-41 B (RAP E44.95) £39.95 buttoms OTHER CALCULATORS F -8C E9.95; 111QS-34B £14.95; F-200 £12.95; 950S- WITH CLOCK, ETC. Only £39.95 4213 £17.95; 9505-3613 £19.95; 56QS.38B 624.95; PW.81 £14.95; AQ.1500 £14.95; MQ-6 £19.95; MQ-12 5605-50B £34.95; 81C1S.408 £24.95; 29CS-498 £19.95; AQ-2200 £19.95; ML -71 £22.95; ML -81 £29.95. £22.95; HR -10 E29.95. SCIENTIFICS. With clock. EX -7100 £24.95. Others: LADIES' CASIO 10 models from £12.95 FX 81 £12.95; FX 100 £15.95; FX-330 £15.95; FX510 £19.95; 3P00 £21.95. ILLUSTRATED CATALOGUE RETURN OF POST SERVICE Casio and Seiko products. Send 25p to. TEMPUS (Information and Service Centre), 19-21 Fitzroy Street, Postal and telephone orders received before 4.00 p.m. II normally be despatched the same day by FIRST CLASS POST. Cambridge CB1 1 EH (Refundable on purchase). Send your order by FREEPOST (2nd class post - no stamp required). Please phone urgent orders or use first class Ma4. PRICE includes VAT, P&P. Send your Tempus (Dept. ETI) Company Order, Cheque or P.O. or phone FREEPOST, 164-167 East Road your ACCESS or B'CARD number to: TEMPUSCambridge CB1 1BR. Tel. 0223 312866 ETI JULY 1980 93 MONEY SAVING BARGAIN HIGH GEC STEREO Limited stocks EX -STOCK FROM US QUALITY Superb Value J.V.C. BELT DRIVEN 10+ 10 watt AMPLIFIER Don't delay TURNTABLE WITH AM/FM STEREO TUNER -. , order one today WITH STEREO MAGNETIC IDEAL FOR THE HOME AUDIO TECHNICA A cancelled export order CARTRIDGE brings you this offer fromtheworld- ,. famous firm of G.E.C. ,..... A/Whit-4H ----..! AM/FM stereo Tuner Amplifier Ready built. Comprising of a tuner. pre -amp. board and ..,,,' separate power supply:power amp. board with wiring diagram. Rotary Controls: Tuning. on/off volume. balance. ".1 Jfr -,-, treble. bass. Stereo Beacon indicator. Push-button Controls. Mono. Tape. Disc.A.F.C.. F.M. rixri. LW, MW. SW. LOW Power Output: 7 walls HMS per channel. at better LIST PRICE OVER £50 AFC FM L MW SW Tuning. than 2% THD into B ohms. ID watts speech and PRICE ON/OFF BALANCE. TREBLE.BASS. MONO TAPE Phono J.V.C. Turntable supplied corn- music. Volume Response: 60Hz-20KHz within--3da OFFER plete Y plete with Audio Technica AT10 Tape Sensitivity: Output - typically 150 mv.- Input -- - stereo magnetic cartridge. 300 me for rated output. GuaranteedEx-Stock driven BeltFullyDisc Sensitivity: 100 my (ceramic carlridgel Radio: FM IVHFI 87.5MHz-I08MHz. ONLY 'S' shaped tone arm. Long Wave 145KHz-265Kltz SUITABLE Medium Wave 520KHz-1620KHz. PAIR POST Modern design SPEAKERS £19.95 £19.95 Full size 12" platter. Short Wave 5.8KHz-16MHz, 10 WATTS INC. E2.50 Pair -,- VAT (2 99 Size: Tuner - 2' iin. a I5in. x 7' An. Power Amp - 2in, IN CABINETS VAT CARRIAGE E2 50 Calibrated counter balance x 7',in. x4' fin. weight (0-3 grms). Anti -skate (bias) device. Size - In" x 15'.." (approx) CAR STEREO CASSETTE MECHANISM made for MOTOROLA ONLY £7.50 AT ONLY Front loading 1 2 volt transistorised * Limited stocks * Speed & Voltage control * Size INC VAT LISTOCKSTES £25.99 MI** Ex -equipment - Tested 0 K. * Takes standard C60 cassettePOST 80p PLUS VAT £3.89 Post 12 50 PRO M25 Professional capacitor boom -arm microphone by Eagle. LIST PRICE I. A graceful 60 cm boom -arm capacitor studio microphone using a cardioid capsule A high 1 37 40 r _ _ (2011.1" standard of finish for in -vision use and yet robust enough lo withstand long periods between OUR PRICE NEAIRys liANCLAKAF10. maintenance. Supplied complete with Ired and I black windshield and 6 metres Al twin £19.95 Ion n,,,s k,,- Phone (01) 723 1008/ 9 ih.L.61==oi screened cable terminating al the microphone end in an RR connector. .. Impedance: 600 ohms {floating'. Response: 201 8.000 Hz, Sensitivity: - 70 dBV. Inc VAT 404 Edgware Road, London W2, England I.E.D. Cable: 6 metres two conductor shielded. Connector: SLR 3.11C. Battery type: HP7, POST El 50 PORTABLE PRECISION A RANGE OF 31/2DIGIT LCD MULTI - METERS OFFERING HIGH PRECISION AND EXTENDED BATTERY LIFE. ALL TYPES t FEATURE FIVE FUNCTION OPERATION (AC £ P & PVATTOTAL AND DC VOLTS, AC AND DC CURRENT, LMM-20037.751.00 5.8144.56 RESISTANCE) WITH ABILITY TO CHECK LMM-200144.95 1.00 6.8952.84 DIODES. 0.5" LCD DISPLAY WITH 1.50 11.56 'BATTERY LOW' WARNING. AUTO - LMM-10075.55 88.61 POLARITY, AUTO -ZERO. FULL JEST LEADS 1.95 0.25 0.33 2.53 PROTECTION AGAINST TRANSIENTS AND OVERLOADS WITH ABILITY TO WITHSTAND MAINS ON ANY RANGE. RUGGED ABS CASES AND A COMPREHENSIVE 1 -YEAR WARRANTY The LMM-200 is a compact handheld multimeter with 0.5% basic accuracy and 15 different ranges. It Lascar Electronics Ltd., Unit 1, Thomasin Road, Basildon. Essex. Telephone No: Basildon (0268) 727383. measures AC/DC voltage from 0.1mV to 500V, AC/DC current from 0.1µA to 2 Amps and resistance from ft to 2Mit. 200 hour battery life. To: Lascar Electronics, Unit 1, Thomasin Road, Basildon, Essex. The LMM-2001 is an identical instrument but with a 0.1% basic accuracy. Please send me Data LMM-100 £88.61 LMM-200 £44.56 LMM-2001 £52.84 - TEST LEADS £2.53 The LMM-100 is suitable for field or bench use. It has a basic accuracy of 0.1% and 25 different ranges. It Name measures AC/DC voltage from 0.1mV to 1KV, AC/DC Address current from 0.1µA to 2 Amps and resistance from 0.1 ft to Tel No 20M.11. Battery life is over 2,000 hours. It also features a unique 'digital hold' facility and adjustable carrying handle. I enclose cheque/P 0 value 94 ETI JULY 1980 PROJECT LOUDSPEAKER PROTECTION MODULE Modern transistorpoweramplifiersuse the technique of DC coupling between the low levelMake your loudspeakers immune amplifier stages and between the output stages and the loudspeaker. This has the advantage of removingto everything except music and coupling capacitors from the signal path, decreasing parts count and improving performance at low frequencies. the End of The World with our Older transistor amplifiers used a single supply rail so the transistors operated between the supply voltagecomprehensive protection and ground. Since an AC signal has both negative and positive excursions the power amp was designed so thatcircuit. a DC voltage was present on the output stage. Positive excursions would cause an increase of this DC voltage while negative excursions decrease the voltage. Since DC cannot be applied directly to a loudspeaker it was necessary to insert a capacitor, called a blocking or out- putcapacitor,betweenthe output stage and the loudspeaker. The load impedance of the loudspeaker is around 8R so the capacitor has to be 5000 uF to 10,000 uF before an acceptable low end performance can be obtained. The solution to these problems was DC coupling. The power amp is run from a 'split supply' so that the output transistors are supplied from apositive and negative supply voltage. The average of these supply rails is zero volts, so the output can be connected direct- ly to the' loudspeaker. Both positive and negative excur- sions are possible due to the split power supply. Coupling Fault Unfortunately, DC coupling also has its disadvan- tages. The biggest of these is the possibility of damage to the loudspeakers in the case of power amp failure. Since all the stages are DC coupled, a fault anywhere in the power amp can cause the output stage to swing hard against one of the supply rails. The most common power amp fault is a condition in which one or several of the output or driver transistors is destroyed, and this almost always causes the full DC voltage from one of the supply railsto be applied directly to the loudspeaker. The loudspeaker cone is slammed against the suspension and the power dissipation in the voice coil causes a rapid in- crease of voice coil temperature. In this condition most woofers will survive for only a few seconds. This type of fault is all too common and is the most expensive fault likely to occur in a modern hi-fi system. Some top line amplifiers have built in protection circuits with relays that disconnect the loudspeakers should this condition occur, but these are the minority. ETI JULY 1980 95 1C1a,IC1b NOT USED R4 1M 03 Db 220k 10 0 IC1c1 I IC1c C3 D1-D4 ARE 1N914 D5,6 ARE 1N4004 TO ONE CHANNEL ONLY SHOWN LOUDSPEAKER COMPONENTS ARE NUMBERED STARTING AT 100 FOR SECOND CHANNEL ie R101 , R102 Fig.1 (above) The circuit diagram for the loudspeaker protection unit. not place a significant load upon the amplifier itself during usage, such Note that one channel only is shown and that on the PCB components that the damping to the speaker is unaffected. Secondly the high input for the second channel are numbered from 100 to avoid confusion. impedance of the protector ensures that a load -sensitive amplifier is Relay R LA1 should be a 12 V type with the facility for one, at least, pair unlikely to be pushed into colouration by your decision to save your of changeoi,.er contacts. This project has been designed such that it does loudspeakers from destruction if it cracks up. Remedy This circuit 'looks' at the loudspeaker wires and pro- HOW IT WORKS tects the loudspeakers in two ways. The presence of any The signal voltage from the amplifier is rectified by a full -wave DC automatically trips the relay and disconnects the bridgeconsistingofdiodesD1,D2,D3 andD4.The loudspeaker. The protector also looks at the amount of potentiometer RV1 and the resistor R1 and capacitor C1 form a potential divider that determines the sensitivity of the circuit. At power applied to the loudspeaker. It allows high power normal signal frequencies C1 has a relatively low impedance and transients but will disconnect the loudspeaker if the ap- the resistance across the diode bridge becomes that of resistor plied power exceeds the loudspeaker rating for more R1, i.e: 15 k. As the frequency approaches DC however, the than about 50 milliseconds. In this way the advantage of impedance of this capacitor increases, increasing the sensitivity of the circuit. If a DC voltage is presented to the input C1 acts as the improved high power amplifiers is not lost but the an open circuit and the protector is therefore atits most loudspeaker is still protected. The circuit includes a two - sensitive. second monostable delay circuit so that the loudspeaker Signal voltages from the full wave rectifier are averaged by the is reconnectedapproximatelytwo capacitor C2 and R2, and then applied to a Schmitt trigger. The automatically Schmitt trigger is formed from the resistors R3, R4, ICIc and IC Id. seconds after the 'fault condition' has been removed. This circuit will only respond to a voltage level greater than a The project isdesigned around two standard CMOS preset amount. When this voltage is exceeded (around 6V5 in this ICs. This ensures a very low current consumption and ob- case) the output goes positive charging C3 through diode D5. viates the need for a power switch. This is important This diode prevents C3 from being discharged by the Schmitt trigger when its output goes low again so the capacitor can only since a fault with an amplifier could well occur at the be discharged by the 10 M resistor R5. This takes about two moment ofturn -onandit is essentialthatthe seconds to this circuitis in reality a simple and effective loudspeaker protector is already on. When the relay monostable. Another two stages of the IC drive the transistor trips, the circuit pulls around 50 mA for each relay so it is which is in series with the relay coil. Diode D6 protects the transistor from large back-EMF voltage spikes produced when the important that battery is capable of supplying 100 mA relay is turned off. during relay operation. There should be no problem with the battery lasting for its shelf life, providing the relays are not tripped more than very occasionally. Construction Solder the resistors, capacitors, diodes and relay first. The diodes and electrolytic capacitors must be in- serted the right way round as shown on the pc board overlay. Lastly, solder the transistors and ICs on the board. Again, these devices must be oriented correctly. Testing The prototype was constructed in a general purpose Check the orientation of all polarised components steel box but this is not critical. The front panel is fitted including the transistors and ICs. If allis well cut two with a stereo 100k potentiometer. This sets the trip point short lengths of speaker cable and connect the output of of the protector so that it can be adjusted for your par- the amplifier to the input of the loudspeaker protector. ticular loudspeakers. The rear panel holds the terminals Connect the speaker cables to the output of the protec- for the wires from the amplifier and loudspeakers. The tor. Now switch on the hi-fi system. Choose music with wiring to the rear panel and to the front potentiometer is reasonably even amplitude for this test. Turn the front shown in the wiring diagram. panel level control on the loudspeaker protector for the Finally, make the connection to the battery. lowest power and slowly increase the amplifier volume. 96 ETI JULY 1980 PROJECT: Loudspeaker R102 100k 4°v-- :711 9f1 0101 D103 OV from BATTERY 104 +9V from BATTERY. RL1 RL101 from RV1 from RV101 to SPEAKER (chA) to SPEAKER (chB) from AMPLIFIER (chA) from AMPLIFIER (chB) Fig.2. (above) The component overlay for a stereo version of the PARTS LIST loudspeaker protection module. Note the '100 upwards' component numbering of the second channel. Apart from the battery connections, Two of each of the following is required for stereo. the PCB is,in fact, symmetrical. Mains power was not employed because it is important that the module is operating at amplifier power Resistors all 1/2W, 5% up and the best way to ensure this is to use battery power! In normal use R1 15k the battery (PP6) will last well-nigh its normal shelf -life as it draws vir- R2 100k tually zero power until tripped. If you run the circuit so that it con- R3 220k tinually operates something is amiss - so stop it! R4 1M R5 10M Potentiometers RV1 100k lin. (dual) Capacitors C1 470n polyester C2 10u 25V electrolytic C3 220n polyester C4 100u 25V electrolytic BUYLINES Nothingunusualusedinthiscircuit, so yourlocal Semiconductors neighbourhood component emporium should be able to supply Q1 BD139 with no problems. D1-134 IN4002, or similar One thing we have heard in the past is that high value 5% 135, D6 IN914 or similar resistors are not easy to obtain. In this design lower values of R4 IC1 4049B and R5 must not be substituted. When the power to the loudspeakers exceeds that set by system is being strained. Set the loudspeaker protector the potentiometer the protector should trip in and dis- so that it trips just below that volume where distortion connect the loudspeakers. starts to occur. Turn the amplifier down, and the loudspeakers We have done extended tests on the protector, even should be reconnected after about two seconds. Since to the point of connecting expensive loudspeakers and loudspeaker power figures are a rather dubious quantity, inducing power amp faults that would otherwise destroy it is probably best to establish the correct setting for the a loudspeaker in seconds.Inallof these tests the loudspeaker protector experimentally rather than just loudspeaker protector has performed well and itisa settingittotheratedpowerhandlingofyour comforting thought that should a power amp fault oc- loudspeakers. Your ears are the best indication that the cur, it will not take your loudspeakers with it. ETI 97 ETI JULY 1980 All these advantages... PLEASE MENTION ETI WHEN REPLYING Instant all-weather starting Smoother running Continual peak performance Longer battery & plug life TO ADVERTS Improved fuel consumption Improved acceleration/top speed Extended energy storage BUILD YOUR OWN ..in kit form FM C103ICV L SYSTEM SPARKRITE X5 is a high performance, top quality inductive discharge electronic ignition system designed for the electronics TRANSMITTER BASIC KIT £36.00 D.I.Y. world. It has been tried, tested and.proven to be utterly RECEIVER KIT £18.40 reliable. Assembly only takes 1- 2 hours and installation even less due to the patented 'clip on easy fitting SERVOS from £12.00 The superb technical design of the Sparkritecircuiteliminatesproblems of the Send remittance of £2 for circuits and constructional data to. contact breaker. There is no misfire due to contact breaker bounce which is eliminated electronically by a pulse suppression TELERADIO R /C, 325 FORE STREET, EDMONTON circuit which prevents the unit firing if the LONDON N9 OPE, 01-807 3719 points bounce open at high R.P.M Contact breaker burn is eliminated by reducing the Current by 95% of the norm CLOSED THURSDAYS There is also a.unique extended dwell circuit which allows the coil a longer period of time to store its energy before discharging to the plugs. The unit includes built in static timing light, systems function CLEF KITS - light, and security changeover switch Will work all rev -counters NEW - Fits al112v negative -earth vehicles ELECTRONIC ROTOR Two.speed organ rotor simulator plus a with coil/distributor ignition up to 8 cylinders. three-phase chorus generator on a single THE KIT COMPRISES EVERYTHING NEEDED PCB (8"x5") Kit includes all components - IC sockets throughout - mains opera- Die pressed case. Ready drilled, aluminium extruded tion and stereo headphone driver PCB. base and heat sink, coil mounting clips and accessories. All kit Easily integrated with existing organ components are guaranteed for a period of 2 years from date of Component kit E89.00. purchase. Fully illustrated assembly and installation instructions are included. KEYBOARDS Roger Clark the world famous rally driver l,'ve believe that we have located the best says "Sparkrite electronic ignition systems High Quality Electronic Musical In- manufacturer of square front Keyboards are the best you can buy" struments under the personal supervi- as used in our Kits and can also supple sion of Specialist Designer A. J. Keyswrtch hardware including the in BOOTH MAN. dustry standard soft plated contact springs JOANNA 72 & 88 PIANOS 49 NOTE C -C £23.80 Six and 11/4 Octave Electronic Pianos with unique Touch Sensitive Action as used in 73 NOTE F -F £37.00 the P E JOANNA, which electronically 88 NOTE A -C £45.00 simulates piano key inertia - a feature All Keyboards are easily cut to provide HIGH PERFORMANCE not available in any other designBuild your required length and compass Quay this widely acclaimed professional instru- My enquiries welcome ELECTRONIC IGNITION ment. for either Domestic or Stage use from our top quality Component kits SIX OCTAVES- £207 BUILDING SERVICE 71/4 OCTAVES- £232 We are specialists in Electronic Piano Electronics Design Associates, Dept. ET1 /7 P.E. STRING ENSEMBLE Manufacture and can build your Piano for 82 Bath Street, Walsall, WS1 3DE Phone 109221614791 The versatile String Synthesizer with a you - see lists fantastic sound at an economic price Split Name Keyboard facility with a range of impress- INFORMATION ive voices Please send S A Equoting items of Address COMPONENT KIT- £169 interestTelephone BARCLAYCARD Back up TELEPHONE advice is avail- orders can be accepted all prices include able from the designer to supplement V A Tcarriage & Insurance the clear instructions included with the above Kits VISITS Phone your order with Access or Barclaycard ant welcome Us appointment otherwise I enclose cheque PO's for P.A.'s - SPEAKERS - Mal Order Only Inc VAT and P P QUANTITY 8E0'0 CABINETS Units can be supplied to add to the EXPORT Enquiries welcome - In Australia please X5KIT 16 95 Cheque No. Component Kitsincluding Domestic or Stage Cabinets and portable tubular legs contact JAYCAR (Sydney) ACCESS OR BARCLAY CARD he Send SAE d brochure ante moored CLEF PRODUCTS (ELECTRONICS) LIMITED E'DT.I.ew.) 16 Mayfield Road, Bramhall, Cheshire SK7 1JU. 061 439 3297 98 ETI JULY 1980 PROJECT LINEAR FREQUENCY METER A project dedicated to all those hundreds of times you've needed to know one cycle from another and been frequently left wanting. HIGHER FREQUENCY \ LOW FREQUENCY INPUT --- PULSE - LOW FREQUENCY METERREAD- LOW HIGHER FREQUENCY PULSE - METER -a READS - HIGHER Above: waveform diagrams which indicate two possible sources of incorrect reading using a DFM. The drawingsareself- explanatory on the whole. There are many applications in the home workshop where simple audio frequency measurements are Circuit Features required. When experimenting withoscillators, The circuit generates a series of short pulses at the building or repairing function generators etc, itis often same frequency as the input. These pulses drive a handy to have some means of measuring frequency - moving -coil meter the current through which will be the accuracy to the last Hertz is not always required and average amplitude of the pulse waveform; that is, it will thus a full-blown digital counter is not warranted. integrate the pulses. This average will be proportional to This project will enable you to measure frequency the ratio of time the pulse is on to the time it is off. The from around 100 Hz right up to 100 kHz with an ac- time the pulse is on, that is - the pulse width, is fixed. At curacy of a few percent. Itis inexpensive to build but low frequencies, the time the pulse is off will be much, performance is quite adequate to meet a large number much longer than the time the pulse is on. Thus, the of needs in any hobbyist's workshop. Accuracy is unaf- average current through the meter will be quite low. At fected by the waveshape of the signal being measured higher frequencies, the time between pulses will be quite and the unit will accept signal levels as low as 200 mV. short and the average current through the meter wilrbe The input is fully protected against high signal levels and quite a bit higher (as shown in the diagram). Thus, as the against DC voltages up to the rating of the input frequency of the pulses is proportional to the input fre- capacitor, C1. The input is also fully floating above earth quency, the pulse on/off ratio, and therefore the meter - a useful feature. current, will be proportional to the input frequency. The The frequency meter may be powered from an inter- meter can be calibrated directly in frequency as the rela- nal 9 V battery or from a battery eliminator. A suitable tionship is a linear one. We have used a 100 uA move- socket may be installed on the rear of the cabinet. ment for convenience as it does not have to be rescaled. 410- ETI JULY 1980 99 0 OFF 100 kHz SW1b RIO 1 R12 R9 10k 1k0 IMO 100k /1000, 105 Hz IkHz30- 0 R7 2 33k SV" 100kHz 100Hz GANGED Cl 0 OFF 4700 R4 HIGH MO -r 9V C3 INPUT 8 Cl 5611 C5 02 4- Ow 100 0 3 6 IC2 3 \ Ars Rn 013 IMO R8 3900 221, C2 RV1 22k R14 33k 14 608 ZDI 5V6 MI 100uA Fig.1. A full circuit diagram for the linear frequency meter. HOW IT WORKS The circuit consists of an op -amp operated as a Schmitt trigger to The output of IC1is a train of square waves at the same amplify and square the input signal, followed by a 555 timer frequency as the input. The output of IC1 is differentiated to wired as a monostable, giving a short output pulse of fixed width provide shorttriggerpulsesforthe 555 timer,IC2. The for each cycle of input sigrial. This pulse drives a moving -coil differentiating network consists of C3, R7 and R8. This network is meter, the reading being an average of the pulse amplitude, arranged to provide a trigger pulse that is always shorter than the which is proportional to the pulse frequency. As the pulse output pulse of the 555. Capacitor C3 is selected to give the frequency is directly related to the input frequency, the meter shortest possible pulse to the 555 consistent with reliable reading is directly proportional to the input frequency. triggering. The inputsignal is coupled into IC1 via C1, which provides DC The output of the 555 monostable will be a pulse of fixed blocking. Protection from overload caused by high amplitude width, determined by the range resistors, R9 to R12, and input signals is provided by a diode clipper consisting of D1, D2 capacitor C4. The ranges are arranged to give a 75% output duty andR1.The diodes are connectedinan inverse -parallel cycle at frequencies of 100 Hz, 1 kHz, 10 kHz and 100 kHz on the arrangement so that both positive and negative peaks, above the input. diode forward conduction voltage, are clipped. IC1isa fast op -amp connected as a Schmitt trigger with The output pulse from the 555 is clipped at 5V6 by a zener amplification, as mentioned above. Resistors R5 and R6 provide diode, ZD1, to avoid inaccuracies caused by falling battery hysterisis, a 'dead band' in the action of the Schmitt, centred on voltage (as the battery ages). The meter responds to the average zero input level. This dead band ensures that the Schmitt ignores value of the clipped pulses. As the frequency increases, the duty noise pulses. cycle (on/off ratio) of the pulse train increases, increasing the As the unit is required to operate from a single supply, for average voltage and thus the meter current in direct proportion. convenience, R2 and R3 bias the input of IC1 at half the supply Thus the reading on the meter will be linearly related to voltage. frequency. The lowest range is 100 Hz full-scale deflection, the highest, 100 kHz. Construction As mentioned previously, we constructed our pro- Only two cheap IC's are used in the whole design, a totype in a plastic box. This has the advantage that the 3140 op -amp and a 555 timer. The 3140 amplifies and unit can be operated fully floating from earth - handy squares the input signal and was selected for its high in some situations. Check placement of components on slew rate, wide frequency response and high input im- the front panel and the positioning of the PCB inside pedance. The output of this stage will be a square wave before commencing major assembly. It's probably best ofthe same levelforallinput signallevels and to assemble the components on the board first. Take waveforms. care with the orientation of the ICs, diodes and tantalum capacitor. The pulses are generated by a 555 timer connected The input capacitor, C1, can be obtained in several as a one-shot monostable giving a single pulse output for voltage ratings. Polyesters are available in ratings of 100 ch input cycle. The monostable has four ranges giving V, 250 V and 630 V. If all your work is with solid-state cir- dede scales on the meter. A fifth position on the cuitry, a 100 V type will be more than adequate. If you switcis used as a power switch. anticipate using your unit with say, valve equipment, the highest rating type for C1 is recommended. The rating Regulation of the output pulses by a zener diode applies to the combined voltage that may be present on preserves the accuracy of the unit with falling battery the input, plus the possible peak value of the input voltage. signal. 100 ETI JULY 1980 PROJECT: Frequency Meter HIGH INPUT TO SW1a LOW 0111/1 2 / wiper Fig.2. Component overlayfortheETI Linear Frequency Meter. Note the input and -111144345)M1 ZD1 RV1 R14 3.3k output connections from the PCB carefully. A couple of crossed wires here and ... OV FROM BATTERY PARTS LIST BUYLINES Resistors All 1/2W, 5% R13,5,11 10k As one of the criteria in designing the project was that it would R4,6,9 1M0 be assembled from easy to obtain bits and pieces, it is (or should R7,14 33k belunlikely that any problems will be encountered in that area! R8 22k Boxing is not critical at all and the ever-present Vero range R10 100k would serve as well as the one we employed here. R12 1k0 R13 39OR Potentiometer PR1 22k Trimmer Capacitors C1 470n polyester C2 10u tantalum C3 56p ceramic C4 6n8 polyester C5 100u 25V electrolytic Semiconductors SPECIFICATION D1,2 1N914 or similar Frequency 10Hz to 100kHz ZD1 5V6, 400mW zener diode in four decade ranges IC1 3140 op amp Minimum input 200 mV RMS IC2 555 timer Maximum input 250 V peak AC or DC Miscellaneous (dependent on voltage rating of C1) M1 100uA meter, SW1 two pole five position wafer switch. Supply voltage 9V A 630 V rated capacitor will be physically larger than a 100 V type and the leads may have to be shaped Calibrating It to fit the capacitor on the board. Calibration of the frequency meter is very easy, aided Once the board is assembled, the major components by the fact that it has a very high input impedance. can be assembled onto the front panel of the case. We With the unit switched to the 100 Hz range, touch your made up an overlay for the front panel. finger to the input. There will usually be enough 50 Hz The board may be mounted anywhere convenient in field from the electrical wiring in a building to drive the the case and wires run to the front panel for the input input. This will cause a deflection on the meter and RV1 and switch connections. Make sure the board does not should then be adjusted to give a meter reading of 50 (half get in the way of the meter when the front panel isin scale). Move the unit near house wiring to increase the place. amount of signal to the input if a reading cannot be obtained. The unit may be powered from an internal battery, If a signal generator of known accuracy is available which makes ita handy portable unit.If you wish to the instrument can be calibrated on any range. Only one operate the unit from a plugpack battery eliminator, range need be calibrated as the others will automatically then we recommend you purchase aunit givinga fall into line. nominal 6 V DC output. The current requirement for the If it is impossible to obtain any reading on the meter, project is quite modest and the output of these small the coupling capacitor (C3) may have to be increased in battery eliminators is dependent on the load. A 6 V unit value to say 100pF or 150pF. This component has been will typically deliver 9 V or so under a light load. selected to give a very short trigger pulse into the 555 If you do decide to use one of these units, a socket and has been found to work correctly, using the value matching the unit's plug will have to be mounted on the shown in the circuit, with several different ICs. rear panel and leads run to the supply rail pads on the board. If you wish to have the option of both battery and Selecting the 100 kHz range will connect power to the mains operation, then a small SPDT toggle switch should unit and the unknown signal can then be applied to the in- be mounted on the rear panel also and wired into the circuit. put. Set the reading and switch to a lower range if required. ETI ETI JULY 1980 101 1171_.171 4 2 QUARTZ LCD QUARTZ LCD ALARM. Alarm/Chronograph. QUARTZ LCD Slim 22 functions. Hours, Gt,. TS QUARTZ GENTS QUARTZ LCD. Chronograph. 1 1 - 6 digit, hours, mins, secs, SAME AS 1 - Alternative function.Hours,mins, day, date. 24 -hour alarm mins,secs, day, LCD,5 -function. date,month,1/10 Hours, minutes, secs, style. secs, 6 digit -month, date, with on/off indicator. sec stopwatch, split month,date,back- ONLY £4.95 day of week, 1/100 sec ONLY £8.95 light. stopwatch, split and lap and lap modes, 12 modes, backlight. and 24 hour modes, ONLY £4.95 24 hour alarm. ONLY £7.95 ONLY £14.95 IWe don'tbelieve you 6 can findbetter value combined with quality, QUARTZ LCD than these - our special Musical Multi - introductoryprices. Alarm/ Chronograph. Compare the savings we 6 -digit. Hours, mins, secs,day,date, offer and order now. 1/100 second stopwatch, split and lap modes, 24 hour 14CREDIT CARD alarm, countdown CALCULATOR. Very timer/alarm,dual slim with standard 4 time zone. functions plus ONLY £14.95 memory,percentage and squareroot. Complete with a mock 7 leatherwalletwith credit card pocket. ONLY £6.95 QUARTZ LCD 13BELTIME 29F. Alarm/ Memory Bank/ Chrono.Advanced Alarm. Normal time, andaccurate,this alarm and snooze watch has 8time alarm functions with a functions,4alarm completemonth's functionsand 17 calendar displayed at chronograph func- the press of a button. tions.Complete with backlight and stainless ONLY £16.95 steel bracelet. ONLY £19.95 0 12 GENTS ANALOGUE LADIES QUARTZ QUARTZ. Conven- LCD. 5 -function as tionaldisplay,ac- Gents No. 1 curacy normally Available with black associated with digital or white face. watches.Automatic calendar, elegant and ONLY £5.95 robust. ONLY £19.95 11 9 LADIES QUARTZ LCD. SAME FUNCTIONS AS 8. - Alternativestyle. Available with black or LADIES QUARTZ white face. LCD SAME AS10. Alternative "Round" All watches have fully ad- ONLY £5.95 shape.Availablein justable, matching gold or silver colour. stainless steel straps, and demonstrationbattery fitted (this battery is not ONLY £8.95 guaranteed).Please add 10 60p for each spare battery required. LADIES QUARTZ All products carry a Full 7 - LCD. 5 functions. Day Money -Back Reassu- Dress Style. Functions rance,plus12 -Month same as1. Available Guarantee. Prices include in gold or silver colour. VAT ONLY £8.95 Please send me Items dist numbers'. Send stamped addressed I enclose cheques POs for/ envelope forColour NAME I Brochureof120 other 78 CASTLE STREET, bargains. ADDRESS MELBOURNE, DERBY, I DE7 1 DY Please add 35p Pr P per item 102 ETI JULY 1980 PCB FOIL PATTERNS ETI nvIAGE 0 CO.ORDINATOR t DIGISOUND 80-8 ONNOmICChftci 00 00 Ommininamma O 80 00 00 04) 00 OimlimmOsna °eS3C\N -44ETI 0 ETI JULY 1980 103 0 ETI IMAGE CO-ORDINATOR Topside --1- 4 ETI IMAGE CO-ORDINATOR Bottom 0 0 0 0 104 ETI JULY 1980 PCB Foil Patterns O O O O BATTERY - LOA ETI LOUD SPEAKER PROTECTOR ETI JULY 1980 ccr-im)/,,LN,J1 10512. ETCH RESIST TRANSFER KIT SIZE 1:1 Complete kit 13 sheets 6in x 41/2in £3.00 Codespeed with all symbols for direct application to P.C. board. Individual sheets 30p each. ARE YOU (1) Mixed Symbols (2) Lines 0.05 (3) Pads (4) Fish Plates and Connectors (5) 4 Lead Electronics and 3 Lead and Pads (6) DILS (7) BENDS INTO THE P.O. BOX 23, 34 SEAFIELD ROAD, COPNOR, 90and 130'(8) 8-10-12 T.0.5. PORTSMOUTH. HANTS, P03 5BJ Cans (9) Edge Connectors 0.15 (10) Edge Connectors 0.1 (11) Lines 0.02 (12) C.B. SCENE? REJECT FLUORESCENT CALCULATORS, modern, fluorescent 10 function calculators with memory Most Bends 0.02 (13) Quad in Line. repairable but no guarantees£2.99 each ALARM CLOCK I.C. MM5316, brand new, with date E2.29 each POLARIZING FILTER 0.006" thick plastic film FRONT AND REAR PANEL If so, a 9" x 4" SAE will bring you Any size cut. max size 19" by 250 feet 2p per square inch DIGITAL MULTIMETER CHIP MM5330 I C to TRANSFER SIGNS free details of our carefully build a 41/2digit multimeter With data E3.49 each All standard symbols and wording. Over WRISTWATCH LCD supplied with polargers and selected range of C.B. data 99p each 0.8" LED DISPLAY 4 digit, common 250 symbols,signs and words. Also cathdoe with data. E3.75 each LED ALARM CLOCK availableinreverseforperspex,etc. Accessories. MODULE with 0 7" high digits with data E5.99 each 10 UNTESTED LED DISPLAYS you to test0 1" Choice of colours,red,blue, black, or digits common cathode 99p. LED WRISTWATCH I.C. Mostek MK5030 with data 95p each LEO white. Size of sheet 12in x9in. Price MAIL ORDER ONLY WRISTWATCH DISPLAY type DIS 50 1, 0 1" digits £1.20. (Matches MK 5030 IC.)With data 95p each. NOTE the MK5030 and DIS501 are inlegless flatpack style package and require some fairly fine soldering 20 KEY GRAPHIC TRANSFERS Post today to CALCULATOR KEYBOARDS, 2 for 99p (not for use with NORTEK 4204 talcchip) REJECT LED CAL- WITH SPACER CULATORS, some repairablebut all good value for spares £2.50 each MINI SLIDE SWITCHES 2 pole ,ACCESSORIES POLAR changeover contacts15p. PUSH-BUTTON SWITCHES spring loaded (momentary) with one no Available also in reverse lettering, colours - contact 14p. LM555 TIMER I.C. supplied with blue,black or white.Each sheet applications booklet 23p each. LED CALCULATOR red, ENTERPRISES DISPLAY 8 digit, common cathode. multiplexed, 0 1" 12in. x 9in contains capitals, lower case digitsWith data 99p 2102 MEMORIES. Static memories for the micro men With data 95p CALCU- and numerals Vain kit or V4in kit. £1.20 2 SWORDERS HOUSE LATOR CHIP. Nortec 4204 4 function and constant complete. State size. With data 80p. MINI REED RELAYS 500 ohm coil 1 2V d cOne no ocontact 79p each QUALITY HIGH STREET SUBMINIATURE REED SWITCHES, brand new All orders dispatched promptly. extremely sensitive 39p each 4" CABLE TIES, 25 All post paid CROWTHORNE, BERKSHIRE tywraps for only 35p. TEL. 03446 71714 Shop and Trade enquiries welcome POST AND PACKING ADD 35p (OVERSEAS ORDERS Special Transfers made to order (24 -hr. Answering Service) ADD f 1) MORE GOODIES IN OUR CATALOGUE. SEND E. R. NICHOLLS MEDIUM-SIZED S.A.E. FOR YOUR FREE COPY. VAT. ADD 15% TO TOTAL COST )INCLUDING P.C.B. TRANSFERS REMEMBER! UNTIL C.B. BE- POST AND PACKING) DEPT. ETI 7 COMES LEGAL WE DO NOT FULL SATISFACTION GUARANTEE ON ALL ITEMS 46 LOWFIELD ROAD SELL RIGS. STOCKPORT, CHES. 061-480 2179 WEST HYDE CASES FOR E.T.I. PROJECTS Soil Probe (July 1979) Order Code BOC 410 Bench Amplifier (August 1979) Order Code WEC 801 Audiophile Pre -Amp (October 1979) Order Code CL2 CDL Audiophile Power Amp (October 1 979) Order Code CL2 CGL Audiophile PSU (October 1979) Order Code CL2 AEL Pinball Wizard (November 1979) Order Code TEK 364 Points Controller (December 1979) Order Code BOC 680 Moving Coil Pre -Amp (January 1 980) Order CL2 ADJ Synthesiser Project Order Code TEK A 23G PLEASE ASK FOR OUR FREE 80 -PAGE CATALOGUE AND PRICE LIST THE BIGGEST SELECTION OF CASES IN EUROPE WEST HYDE WEST HYDE DEVELOPMENTS LIMITED, UNIT 9, PARK STREET INDUSTRIAL ESTATE. AYLESBURY, BUCKS. TEL 0296 20441 106 ETI JULY 1980 8K ON BOARD MEMORY! 2 MICROPROCESSORS 5K RAM 3K ROM or 4K RAM. 4K ROM (link Z80 the powerful CPU with 158 instruction, including selectable). Kit supplied with 3K RAM, 3K ROM all 78 of the 8080. controls the MM57109 number System expandable for up to 32K memory. cruncher. Functions include +. squares roots, logs,,gxponentiab, trig functions, inverses etc Range 10''' to 9 x 19s* to 8 figures plus 2 exponent 2 KEYBOARDS! digits 56 Key alphanumeric keyboard for entering high level language plus 16 key Hex pad for easy entry of machine code. EFFICIENT OPERATION Why waste valuable memory on sub routines for GRAPHICS! numeric processing? The number cruncher handles 64 character graphics option - includes everything internally) transistor symbols! Only El 8.20 extra! MEMORY MAPPED RESIDENT BASIC high resolution VDU circuitry using discrete with extended mathematical capability. Only TTL for extra flexibility. Has its own 21< 2K memory used but more powerful than memory to give 32 lines for 64 characters. most 8K Basics, KANSAS CITY 1K MONITOR low error rate tape interface resident in EPROM SINGLE BOARD DESIGN Even keyboards and power supply circuitry on the superb quality double NEW FACTORY sided plated through -hole PCB. UP! PRICES DOWN! COMPLETE KIT Increased capacity at our fi COMP 80 NOW ONLY big new factory means many prices down! All others frozen! Cabinet size 19.0" X 15,7" x 3 3" Television not included in price £225 +VAT PSI Comp 80. Z80 Based powerful scientific computer POWERTRAN Design as published in Wireless World The kit for this outstandingly practical design by John Adams published in a series of articles in Wireless World really is completer Included in the PSI COMP 80 scientific computer kit is a professionally finished cabinet, fibre -glass double sided, plated -through -hole printed circuit board. 2 keyboards PCB mounted for ease of construction, IC sockets, high reliability metal oxide resistors, power supply using custom designed toroidal transformer. 2K Basic and 1K monitor in EPROM S and, of course, wire, nuts, bolts, etc. KIT ALSO AVAILABLE AS SEPARATE PACKS For Mime caterers who crib is throe their purchase or be a personalised potent IM Ed is evadable as separate packs q PCB 116" is 12 E43.20 Pap of keyboards E34.110. forever. a EPROMS 00.00 Torolbel tralstormer all power supply cam ..... ts C17.60. Cabinet limy reggae male from steel really Imeehlelly lielebedl C26.50, P SWWI °really ..... ce any other tingle beard computer including OHIO SUPERHARD lor which d cal be readily meddled Other packs listed le our FREE CATALOGUE PSI COMP 80 Memory Expansion Sys- tem INGP L Expansion up to 32K all insole the computer s own cabinet, 1;;I AP011;3,;;; By carefully thought out engineering a mother board with buffers and its own power supply (powered by the computer s transformer) enables up to cW, cP1-14-4)m7.0* 3 8K RAM or 8K ROM boards to be fitted neatly inside the computer cabinet Connections to the mother board from the main board expansion le CP CP4P socket is made via a ribbon cable 010 CZ. :14g2 Mother board Fibre glass douole sided plated through hole P C 8 8 7" x 3 0" set of all components 4P including all brackets. fixing parts and ribbon cable with socket to connect to expansion plug 1.1144:7 figf*C-11. E39.90 8K Static Fibre glass double sided plated through hole MAW RAM board PCB 5 6" x 4 8" E12.50 Set of components including IC sockets plug and socket but excluding RAMs E11.20 2114L RAM 116 required) E5.00 Complete set of board, components 16 RAMS £89.50 8K Fibre glass double sided plated through hole ROM board PCB 5 6" x 4 8" £12.40 Set of components including IC sockets r arid socket but excluding ROMs E10.70 2708 ROM (8 required) E8.00 Complete set of board. components 8 ROMs E78.50 Value Added Tax not included in prices New Factory on same Industrial Estate Address and Telephone Number unchanged PRICE STABILITY. Order with confidenceIrrespective of any price changes we will honour all pricey in this advertisement until August 31st, UK Carriage FREE 1980if this month s advertisement is mentioned with your order. Errors and VAT rate changes excluded EXPORT ORDERS: No VAT. Postage charged at actual cost plus El 00 handling and documentation. U.K. ORDERS: Subsequent to 15% surcharge for VAT' No charge is made for carriage 'Or current rate if changed POWERTRAN ELECTRONICS SECURICOR DELIVERY: for this optional service (U K mainland only) add E2 50 (VAT inclusive) per kit. SALES COUNTER. If you prefer to collect your computer from the factory PORTWAY INDUSTRIAL ESTATE ANDOVER call at Sales Counter Open 9 a.m .12 noon. 1-4 30 p m Monday - Thursday ANDOVER HANTS SP10 3NM (0264) 64455 ETI JULY 1980 107 Britain's firstcorn' computerkit. The Sinclair ZX80. 1:417 Price breakdown AtIMAL\m00 ZX80 and manual: £69.52 95VAT £10.43 Post and packing FREE ,NTE-G,zot,ffvar/ONS 717-ff s PEEKus,4 17 Aas Please note: many kit makers quote VAT -exclusive prices. 4,04; .\\*IA You've seen the reviews... you've heard the excite- Vvo ccw; IS; ment ... now make the kit! ssx AAVA\WAar This is the ZX80. 'Personal Computer World' gave ftw it 5 stars for 'excellent value.' Benchmark tests 41*7 4470:4\979e4;xcw,. vA IP A 4 A say it's faster than all previous personal com- vA Av\Lv puters. And the response from kit enthusiasts has been tremendous. To help you appreciate its value, the price is shown above with and without VAT. This is so VAlt you can compare the ZX80 with competitive kits that don't appear with inclusive prices. `Excellent value' indeed! The unique and For just £79.95 (including VAT and p&p) you valuable components of the get everything you need to build a personal Sinclair ZX80. computer at home... PCB, with IC sockets for The Sinclair ZX80 is not just another all ICs; case; leads for direct connection to a personal computer. Quite apart from its Fewer chips, compact cassette recorder and television (black and exceptionally low price, the ZX80 has two design, volume production - white or colour); everything! uniquely advanced components: the Sinclair more power per pound! Yet the ZX80 really is a complete, powerful, BASIC interpreter; and the Sinclair teach - The ZX80 owes its remarkable low price to full -facility computer, matching or surpassing yourself BASIC manual. its remarkable design: the whole system is other personal computers at several times The unique Sinclair BASIC interpreter offers packed on to fewer, newer, more powerful the price. remarkable programming advantages: and advanced LSI chips. A single SUPER ROM, The ZX80 is programmed in BASIC, and you Unique 'one -touch' key word entry: the can use it to do quite literally anything from for instance, contains the BASIC interpreter, ZX80 eliminates a great deal of tiresome the character set, operating system, and playing chess to managing a business. typing. Key words (RUN, PRINT, LIST, etc.) The ZX80 is pleasantly straightforward to monitor. And the ZX80's1K byte RAM is have their own single -key entry. roughly equivalent to 4K bytes in a conven- assemble, using a fine -tipped soldering iron. Unique syntax check. Only lines with correct tional computer -typically storing 100 lines of It immediately proves what a good job you've syntax are accepted into programs. A cursor BASIC. (Key words occupy only a single byte.) done: connect it to your TV...link it to an identifies errors immediately. This prevents appropriate power source* ... and you're The display shows 32 characters by 24 lines. entry of long and complicated programs with And Benchmark tests show that the ZX80 ready to go. faults only discovered when you try to is faster than all other personal computers. run them. No other personal computer offers this Excellent string -handling capability -takes Your ZX80 kit contains... unique combination of high capability and up to 26 string variables of any length. All low price. Printed circuit board, with IC sockets for strings can undergo all relational tests (e.g. all ICs. comparison). The ZX80 also has string input - Sockets for TV. Complete components set, including all to request a line of text when necessary. Z80 A microprocessor - new. ICs -all manufactured by selected world - faster version of the famous cassette recorder. Strings do not need to be dimensioned. Z-80 microprocessor chip, power supply. leading suppliers. Up to 26 single dimension arrays. widely recognised as the best SUPER ROM. New rugged Sinclair keyboard, touch - FOR/NEXT loops nested up 26. ever made. sensitive, wipe -clean. Variable names of any length. Clock. Ready -moulded case. UHF TV Rugged. BASIC language also handles full Boolean modulator. flush, Leads and plugs for connection to arithmetic, conditional expressions, etc. Sinclai domestic TV and cassette recorder. Exceptionally powerful edit facilities, allows keyboard. (Programs can be SAVEd and LOADed modification of existing program lines. on to a portable cassette recorder.) Randomise function, useful for games and FREE course in BASIC programming and secret codes, as well as more serious user manual. applications. Optional extras Timer under program control. Mains adaptor of 600 mA at 9 V DC PEEK and POKE enable entry of machine nominal unregulated (available code instructions, USR causes jump to a separately -see coupon). user's machine language sub -routine. Additional memory expansion boards High -resolution graphics with 22 standard allowing up to 16K bytes RAM. (Extra graphic symbols. RAM chips also available -see coupon). AII characters printable in reverse under *Use a 600 mA at 9 V DC nominal unregulated mains program control. adaptor. Available fromSinclair ifdesired (see coupon) Lines of unlimited length. 108 ETI JULY 1980 4 LEThet I =1 5 INPUT A.( 57 PRILET NT PI ( I ) ii FOEIF I *,1 in4 The Sinclair teach -yourself BASIC manual. If thespecifications of the Sinclair ZX80 mean little to you -don't worry. They're all ..411111111111111111111111111 explained in the specially -written 128 -page book free with every kit! The book makes learning easy, exciting and enjoyable, and represents a complete course in BASIC programming -from first principles to complex programs. (Available separately -purchase price refunded if you buy a ZX80 later.) A hardware manual is also included with every kit. The Sinclair ZX80. Kit: £79.95. - IORDER-I To: Science of Cambridge Ltd, 6 Kings Parade, Cambridge, Cambs., CB2 1SN. Assembled: £99.95. Complete! Remember: all prices shown include VAT, postage and packing. No hidden extras The ZX80 kit costs a mere £79.95. Can't FORM Please send me: wait to have a ZX80 up and running? No problem! It's also available, ready assembled, Quantity Item Item price Total for only £99.95. £ £ Demand for the ZX80 is very high: use the Sinclair ZX80 Personal Computer kit(s) Price includes coupon to order today for the earliest possible ZX80 BASIC manual, excludes mains adaptor £79.95 delivery. All orders will be despatched in strict Ready -assembled Sinclair ZX80 Personal Computer(s) rotation. We'll acknowledge each order by Price includes ZX80 BASIC manual, excludes mains return, and tell you exactly when your ZX80 adaptor £99.95 will be delivered. If you choose not to wait, you Mains Adaptors) 1600 mA at 9 V DC nominal unregulated) 8.95 can cancel your order immediately, and your money will be refunded at once. Again, of Memory Expansion Board(s) (each one takes up to 3K bytes) course, you may return your ZX80 as received 12.00 within 14 days for a full refund. We want you to RAM Memory chips - standard 1K bytes capacity 16.00 be satisfied beyond all doubt -and we have Sinclair ZX80 Manual(s) (manual free with every ZX80 kit no doubt that you will be. or ready-made computer) 5.00 NB Your Sinclair ZX80 may qualify as a business expense. TOTAL £ I enclose a cheque/postal order payable to Science of Cambridge Ltd for £ ZXBO Please print Name: Mr/Mrs/Miss_ Science of Cambridge Ltd Address 6 Kings Parade, Cambridge, Cambs., CB21SN Tel: 0223 311488. ETI JULY 1980 109 Simply ahead... POWER AMPLIFIERS ILP Power Amplifiers are o10F1KHz encapsulated within LOAD 80 ON ALL heatsinks designedto 005EXCEPT HV400 AT 411 meet 6 START OF WAVE / total heat FORM CLIPPING dissipation needs. They 0 are rugged and made to 5 0 02 last a lifetime. Advanced circuitryensures their 001 suitability for use with the 1 finest loudspeakers, pick- ups,tuners,etc.using 0 5 I 2 5 10 20 50 x() 250 digital or analogue sound OUTPUT POWER -WATTS R M S sources. Dis- Minimum Output Power tortion Signal/ Size WeightPrice + Model Power ly R.M.S. Typical Noise Voltage in mm in gms V.A.T. at 1KHzRatio HY30 15 W 0.02% 100dB -20 -0- +20105x50x25 155 £6.34 into 82 + 95n H Y50 30 W 0.02% -25 -0- +25105x50x25 155 £7.24 into 8 12 100dB + fl 09 HY12060 W 0.01% 100 dB -35 -0- +35114x50x85 575 £15.20 into 8E2 ., £228 HY200120 W 0.01% -45 -0- +45 100 dB 114x50x85 575 £18.44 into 8 E-2 E2 77 HV400240 W 0.01% -45 -0 100 dB 45114x 100x851 15/4£27.68 into 4 12 .E 4 15 Load impedance - all models 4 fl - ao ILP PRE -AMPS ARE Input sensitivity - all models 500 mV COMPATIBLE WITH ALL Input impedance - all models 100K fl ILP POWER AMPS AND PSUs Frequency response- all models 10Hz - 45 KHz - 3dB POWER SUPPLY UNITS ILP Power Supply Units with transformers made in our own factory are designed specifically for use with ILP Power amplifiers and are in two basic forms - one with Circuitpanel mountedonconventionallystyled laminated transformer, for smaller PSU's - in the other, for larger PSU's. ILPtoroidal transformers are used which are half the size and weight of laminated equivalents, are more efficient and have greatly reduced radiation. PSU 30 t 15V at 10OrnA to drive up to 12 x HY6 or 6 x HY6-6 £4.50+ £0.68 VAT THE FOLLOWING WILL ALSO DRIVE ILP PRE -AMPS PSU 36 for 1 or 2 HY30's £8.10+ E1.22 VAT PSU 50 for 1 or 2 HY 50's £8.10+ [1.22 VAT PSU 60with toroidal transformer for 1 HY 120 E9.75 + E 1.46 VAT PSU 70 with toroidal transformer for 1 or 2 HY120's £13.61 + E2.04 VAT PSU 90 with toroidal transformer for 1 HY200 E13.61+ E2.04 VAT PSU 180 with toroidal transformer for 1 HY400 or 2 x HY200 E23.02 + £3.45 VAT AVAILABLE ALSO FROM WATFORD ELECTRONICS. MARSHALLS AND CERTAIN OTHER SELECTED STOCKISTS 1 1 0 ETI JULY 19 8 0 this time with two new pre -amps TAPE IN ) TAPEc AUX ) RAD r -r HAG GND I L P POWER SUPPLY UNIT SCHEMATIC BLOCK DIAGRAM OF HY6 PRE -AMP, WITH STEREO CONNECTION SHOWN HY6monoHY6-6stereo When ILP add a new design to their audio -module range. there have tobe very special reasons for doing so. You expect even better results. We have achieved this with two new pre -amplifiers - HY6 for mono operation. HY6-6 for stereo. We have simplified connections, and improved performance figures all round. Our new pre -amps are short-circuit and polarity protected; mountingboards are available to simplify construction. Sizes - 14Y6 4 b 20 y 40 ruin HY6-6 90 . 20 r.4(.) mm Active Tone Control circuits provide ± 12dB cut and boost. Inputs Sensitivity- Meg PU- 3mV 100mV Mrc selectable 1 12rnV All others lOOmV TapeO/P Main 0/P - 500mV: Frequency responseD C to 100KHz 3dB H Y6(71(011) £5.60 + VAT r.4L ill LOW DISTORTION - Typically 0.0051 HY6-6 II or() £10.60 le Sli RATIO- Typically 90dB (Mag. P.O.-68M. NO QUIBBLE VATi1.5.1 HIGH OVERLOAD FACTOR -38 dB on Map. P.U. 5 YEAR GUARANTEE Connectors included El LATEST DESIGN HIGH QUALITY CONNECTORS. 1 DAY DESPATCH ON B6 Mounting Board ALL ORDERS 111 REQUIRE ONLY POTS.SWITCHES, PLUGS AND SOCKETS. 78p + 1 2p VAT BRITISH DESIGN AND in COMPATIBLE WITH ALL ILP POWER AMPS AND PSUs. B6-6 Mounting Board MANUFACTURE 99p + 15p VAT El NEEDS ONLY UNREGULATED POWER SUPPLY II5V to ± 50V. FREEPOST SERVICE * ALL U.K. ORDERS DESPATCHED POST PAID see below HOW TO ORDER, USING FREEPOST SYSTEMI - Simply fill in order coupon with payment or Please supply credit card instructions. Post to address as Total purchase price £ below but do not stamp envelope - we pay I postage on allletters sent to us by readers of II enclose Cheque . Postal Orders E International Money Order this journal. Please debit my Access/Barclaycard Account No. NAME ELECTRONICS LTD. ADDRESS FREEPOST 4 Graham Bell House, Roper Close, Canterbury. Kent CT2 7EP Signature Telephone 10227) 54778 Telex 965780 IMO NM MI NM =I ME IMO INN ME ETI JULY 1980 111 Send to : CLASSIFIED INFORMATION ELECTRONICS TODAY INTERNATIONAL 145, Charing Cross Road, London WC2H GEE. Tel. 01 - 439 7449. Semi -Display: - 1 -3 insertions - £6.00 per single column centimetre 4-11 insertions - £5.50 per s.c.c. ALL ADVERTISEMENTS IN THIS SECTION MUST BE 12 insertions - £5.00 per s.c.c. PRE -PAID Classified: - Closing date: 1st Friday in month preceding publication. 23 pence per word (minimum 25 words) Box number on application (Personal ads only) Advertisements are accepted subject to the terms and conditons printed on the advertisement rate card (available on request). SPECIAL PRINTED PURCHASE VIDEO TEMP. GAUGES CIRCUITS 0°-120"C ONLY Remote sensor on 38" capil- liary, snap fitting in 55 mm MUSIC HARDWARE £1.85 hole. Adjustment screw on (Inc] P&P) back. Comprehensive range Constructors Hardware and accessories 10 -amp Connector Block - in units of two MEwiwx.--- _ ,VSe=m segments. Pack of 100 segments. Selected range of popular components £3.00 (incl. P&P) Full range of HE printed circuit boards normally ex -stock, same day despatch at L.E.M. SERVICES 11 competitive prices 239 RUGBY ROAD P C Boards to individual designs gill LEAMINGTON SPA CV32 6DY Resist -coated epoxy glass laminate for the V deograph Q links to the aerial socket of d 1y man with full processing instructions (no somas WARWICKSHIRE unusual chemicals required) your tv and provides a full colour GIANT oscilloscope display. A must for hi-fi, home Alfac range of etch resist transfers and other DIGITAL CAPACITANCE entertainment, discos, organs etc. drawing materials for p choards METER New - signal invert control. integral square wave 1 pF-21.iF in 5 ranges; on board generator. Plus - full details for testing your audio Send 1513 for catalogue. selector. Precision resistor net- system for transient dist ort me crosstalk etc work and giant displays give Complete Luxury cabinet and RAMAR CONSTRUCTOR direct readout in pF, nF and 0F, r29.9q go 0controls. £14.95 Acc. 0.5% ASSEMBLED. ONLY Kit only SERVICES READY -BUILT UNIT £59.95 + E1.50 P&P art111 MASONS ROAD £24.94 including p&p. Over. seas add E1.50 airpost. VV_, Dower House ClIencey Road STRATFORD-ON-AVON Precision Measurements, P.O. ,Bmwood STUART ;.=..ota WARWICKS. TN. 4879 2: Box 70 Giles Lane, Canterbury, Kent CT I 2UU SYSTEMS Ltd Telephone Brentmod(0277t 810244 MEMORY MART .UK 101 "Superboard' 4K RAM COLOUR MODULATOR Memory Expansion E30 each 2114 1 kx 450 small ns £3.75 each MK14 PRINTER Kit £9.95 FOR ALL TV GRAPHICS! Thisfully built, tested and ready to go printer connects + VAT Red. Green Blue inputs (can be mixed) 2708 UV prom 650 small ns . £5.00 each directly to your unexpended MK14 computer. It prints Ready built Inc UHF Available now Nascom Colour Kit P&P 20p 11495,- VAT Moduleor E45.00 plus VAT *Graphics Software C.O.D. 60p extra a full character set of up to 21 characters per line at 50 characters per second on standard paper. You need WILLIAM STUART SYSTEMS MEMORY MART only a simple 12 -volt power supply to driveit.All Dower HouseBillericay Road, Herongate. Brentwood. Essex 19 Weatherby Gardens electronics are included. Only thirty bytes of software CM 13 3SD Tei 102771810244 Hartley Wintney, Hants are required to print characters. Send SAE for sample Barcla card/Access welcome print and full details. Price E112.00. PET COMPUTER 8K. Calculator type keys. SOLARTRON CT436 OSCILLOSCOPE. 2 years old. No manual. £445 o.n.o. Cash MK14 VDU Good condition £60. Akan 4000 Reel to Reel This VDU connects to your MK 14 I/ 0 chip to give a Tape Deck, excellent condition £55. Phone Pigott, Cambridge. Phone 76865 evenings 64 character x 16 Line VDU. On board modulator. please. 64 ASCII and 64 graphic characters. Minimal Beguildy 273. software requirements. Has its own memory (1K). Full flashing cursor controlCrystal controlled for rock steady display Price E59.90. Send SAE for details. SPEED - VERSATILITY - ECONOMY CC MK14 TO Z80 CONVERSION CA Plug this conversion board into your SC/ MP socket and have the power of the Z80, and amazing power of Designed originally for logic wiring applications,ItIs now the AdEC-1 interpreter, with its 4 -function arithmetic. accepted and used extensively throughout Industry, education versatile graphic control, edit facilities. conditional and research. ROADRUNNER is used by hobbyists, students, ATM technicians, designers and engineers. to carry out work oni- lumps. etc. So easy to use, you will learn to use it in a P.C.B. REPAIRS 'ANALOGUE BREADBOARDING 'SIMPLE few hours. Kit price £29.95 incl. postage. Your MK14 LOGIC WIRING 'COMPLEX INTERCONNECTING OF MICROS V E repaired and conversion fittedif required. Machine AND MEMORIES. code monitor available instead of interpreter at same price 2K basic version and extra 1K ram kit E49.95. EURO INTROKIT El 4 84. PROJECT INTROKIT E5.27. PENCIL Send SAE for details. WITH LOADED BOBBIN t2.44. WIRE DISTRIBUTION STRIPS: - R GLUE FIX 20/pkt 6" LONG £2.80. ADHESIVE 0.38(TUBE PRESS P P E3 45 FIX 20Ipkt 2" LONG 42.92. SINGLE EUROCARD HIGH DENSITY Optional extra manna 3 PLANE (38518 PIN OILS) £4.50. DOUBLE EUROCARD, WITH £114.99 6 Total £124 44 A CAPACITY OF 84x18 PIN DILS £7.25. PROJECT CARD HIGH COMPUTER DENSITY S -SIDED 20x14 PIN DILS £2.85. BOBBINS BLUE 4lpkt 42.12 GREEN 4Iphf 12.12 PINK 4/pkt £2.12 GOLD 4lpkt BEST OFFER EVER 42.12. 1 OF EACH COL. £2.20. TINNED COPPER WIRE 4lpkt REPAIRS 0.12. RECOMMENDED SOLDERING IRON FOR ROADRUNNER Camera Kit, Lens, Any computer repaired at a fixed priceEg. MK14 HOBBYIST £4.80. £2.50. Nascom 1£5. Nascore 2 E12. Ring for Please add 40p for p&p r 15% VAT to all orders. Vidicon Er Modulator others. Plus parts and postage FOR FURTHER INFORMATION ON ROADRUNNERPRODUCTS CROFTON PHONE REDDITCH (0527) 61240 evenings SEND LARGE S.A.E.TO:- REDDITCH ELECTRONICS T.J. BRINEASSOCIATES, 21 FERNEY HILL AVENUE fulsll REDDITCH, WORCESTERSHIRE 897 4RU 56B, HIGH STREET, HASLEMERE, Tel: 01-8911923 detForai SURREY. 112 ETI JULY 1980 FOR SALE 200 COMPONENTS £4. 100 diodes 85p. DIGITAL WATCH BATTERY 150 caps £1.50. 100 resistors 85p. All REPLACEMENT KIT mixed. Lists 15p. Sole Electronics (ETI), 37 Stanley Street, Ormskirk, Lancs. L39 2DH. These watches all require battery (power cell) replacement at regular AERIAL BOOSTERS. Improve weak VHF intervals. This kit provides the radio and television reception, price £6. means. We supply eyeglass. non- S.a.e. for leaflets, Electronic Mailorder Ltd., magnetic tweezers, watch screw- driver, case knife and screwback 62 Bridge Street, Ramsbottom, Bury, Lan- case opener, full instructions and cashire BLO 9AGP. battery identification chart. We then supply replacement batteries - you fit them. Begin now. Send LINSLEY-HOOD 75 WATT AMPLIFIERS E7.50 for complete kit and get into constructed and repaired. Power amp a fast-growing business. Prompt TRS 80 modules from £13.75, fully built and tested. despatch. Details free.I. G. Bowman (Dept. ETI), 59 SOFTWARE Fowey Avenue, Torquay, S. Devon. WATCH BATTERY REPLACEMENT CO. (ET14) 11 Percy Avenue. AshfordMiddx., TVV15 2PB NOW TRANSFORMERS MANUFACTURED to specification, many popular types ex -stock. AVAILABLE Fast turn around on volume production. Send FREE 1980 AMTRON CATALOGUE with enquiries to Louth Transformers, Queen new range of kits and equipment cabinets. Street, Louth, Lincs. Tel: (0507) 606436. Send S.A.E. Amtron UK Ltd., 7 Hughenden Road, Hastings, Sussex TN34 3TG. Tel: Hastings 436004. RECHARGEABLE KITSWITCH Hex Keyboards, wired to any BATTERIES format, 25 coloured keys, £12.75, also TRADE ENQUIRIES WELCOME Reed -operated keyboards, up to 40 keys. - FULL RANGE AVAILABLE. S A.E. FOR LISTS. E1.45 lor Booklet. "Nickel Details: 185 Musley Hill, Ware, Herts. Ware Cadmium Power- plus Catalogue. Write or call: Sandwell Plant Ltd.. 2 Union Drive. BOLDMERE. SUTTON COLDFIELD. WEST MIDLANDS (0920) 61944. 35 GROSVENOR ROAD, TWICKENHAM 021-354 9764. or see them al TLC. 32 Cravens Street. Charing Cross. MIDDLESEX TW1 4AD Tel: 01-891 1923 London. W.C..2 CIRCUIT DESIGN, PrototyPe construcifon:i Analogue or Digital, Single Circuits or Corn- FLEXIBLE - EXPANDABLE - BUDGETABLE ,plete Instruments/Systems. Write A. J. ATTWOOD, C.Eng., MIERE, Heathercote, Heatherton Park, Taunton, Somerset, TA4 THE COMMUNITY MIXER KIT 1 ET or Phone Bradford -on -Tone (082-346) 536. CHEAPER THAN A VISIT TO THE PICTURES. Latest top quality films pre- recorded on videocassettes from only £6. Fulldetails from G.T. Technical Video Library (10a ETI), 119 Oxford Street, Lon- don W1R Not just another Mixer - but designed specifically for Hospital Radio, Talking Newspapers and similar users. VHF CONVERTER. (Varicap). 28 to 30MHz Is there such a word as 'Budgetable'! Consult tuneable IF. Highly sensitive unit £7.50 inc. PARTRIDGE ELECTRONICS post. Other models available. SAE data, lists. 56 Fleet Road, Benfleet, Essex SS7 5JN H. Cocks, Cripps Corner, Robertsbridge, or call (03745) 3256 for the answer. Sussex. Tel. 058083-317. Barclay and Access welcome SEIKO ANALOGUE AND DIGITAL QUARTZ. The very latest products at highly: FOR SALE. UK101 uncased, full board 8k competitive prices. Personal service. Un- ram, includes manual plus extras £315 ono. biased advice. Analogue day/date £35. Ultra Also Sinclair PDM35 plus transformer £25. thin dress from £42. Sports 100 from £60. Phone 01-422 9246 (evenings). Digital alarm chrono /timer £39. Calendar BARGAINS FOR THE alarm £45. Dress alarm /timer £52. Calcula- STOP PRESS Superboard Compatible' ELECTRONIC HANDYMAN tor alarm £55. Programmable alarm chrono BRANDED LED DIGITAL £58. Plus many more interesting Japanese UK101 TRS 80 products. Send S.A.E. for illustrated list to: ALARM CLOCKS Powditch-Digital, 5 De-Vere Gardens, Ilford, COLOUR Essex. No callers please YOUR BOOKS ... BOOKS ... BOOKS - Large range of Electronic Books in stock. Send s.a.e. NASCOM! for list. - Servio Radio, Dept. ETI7, 156-8 DAZZLING COLOUR GRAPHICS FOR NASCOM I L 2 Merton Road, Wimbledon, London SW19 Genuine bit addressable "pixel" system for straight- (11 (2) (31 1EG. forward programming ofpictorialormathematical functions. Returned to Service Department within guarantee period 8 Colour display plus 8 colour independent background (1) With alarm repeat - S.R S.P of E17.00 offered at facility. Full documentation with FREE SOFTWARE: £3.15 Inc VAT 77IB METAL DETECTOR. Build the best. powerful sub -routines for vector generation, demon- (2) With luxury lamp and repeat alarm as featured in Special integrated circuits. Printed circuit stration program for animated effects. All runs in Nascom most major U.KMail Order catalogues. S R.S P board and full instructions. Only £12.50 1 without expansion.Complete with UHF Colour £31 00 -offered at ,E7.95 inc. V.A.T. Modulator for operation with normal colour TV set. (3) With integral luxury light and repeat alarm also as inclusive special offer. 117 Horton Road, Superior design allows connection to most other micro- featured in most major U K Mail Order catalogues Brighton BN1 7EG. processor systems - send us diagrams etc of your b & w S P. of 02.00 -offered at E7,45 inc. V.A r video circuitry for free advice. Don't be fooled by the These will be sold as received from our customers with price' this is a top quality product whi,h will transform the existing fault(s) and without guarantee your computer. UK ONLY £5 OSCILLOSCOPE. Standard junk box Discounts available on large bulk purchases components plus approx. another £5. (Total NOMIWED AVPERIOD FOR.E45Plus VAT LI T ATAILABLE PRESCOTT CLOCK AND components approx. £12). This unit plugs =CM WATCH COMPANY LIMITED into TV aerial socket and converts TV to WILLIAM Prescott House. Humber Road. London NWZ 6ER oscilloscope. Circuit and plans £3. Kerr, 27 STUART Coles Road, Milton, Cambridge CB4 4BL. SYSTEMS Ltki 50Hz SUPERBOARDS BRITISH MODEL AD INDEX AJD DIRECT SUPPLIES 60 KRAMER & CO. 40 FROM £159.95 + VAT ALTEK INSTRUMENTS 74 LASCAR ELECTRONICS 94 Fully built. set up and tested AMBIT INTERNATIONAL 6 LB ELECTRONICS 40 AUDIO ELECTRONICS 60 L&B ELECTRONICS 76 AUTHORISED dealer back-up AURA SOUNDS 52 MAPLIN 116 BAYDIS 36 MARSHALLS 66 Free cursor control backspace, etc. tape BI-PAK SEMICONDUCTORS 14 METAC 35 BK ELECTRONICS 16 MICRO CIRCUITS 12 C_T.S.. 1 Higher Calderbrook B.N.R S. 5 MIDLAND TRADING 22 & 23 Littleborough, Lancs. BUTTERWORTHS 55 MONOLITH 36 Tel. Lrttleborough 79332 any time CALCULATOR SALES & SERVICE 76 MOUNTAINDENE 39 CAMBRIDGE LEARNING 75 E. R. NICHOLLS 106 CHILTMEAD 34 NIC MODELS 74 CHROMASONICS 48 POLAR ENTERPRISES 106 CHROMATRONICS 47 POWERTRAN ELECTRONICS 2, 9 & 107 CLEF PRODUCTS 98 PRODUCT LAUNCH LTD. 21 CODESPEED 106 PROGRESSIVE RADIO 74 COM,P, COMP, COMP 115 QUANTUM 91 CROFTON ELECTRONICS 80 J. W. RIMMER 80 C.S.C. 65 R.T.V.C. 83 TIME WRONG? DELTA TECH & CO. 80 SCIENCE OF CAMBRIDGE 108 & 109 MSF CLOCK is ALWAYS CORRECT - never gains or DIGISOUND LTD. 46 C. N. STEVENSON 36 loses, self setting at switch -on, 8 digits show Date. DISPLAY ELECTRONICS 82 SWANLEY ELECTRONICS 79 Hours, Minutes and Seconds, larger digit Hours and DORAM ELECTRONICS 51 TANDY 42 Minutes for easy QUICK -GLANCE time, Auto GMT/ E.D.A. 98 TECHNOMATIC 10 BST and leap year. also second -in -a -month STOP ELECTROVALUE 56 TELERADIO 98 CLOCK and parallel BCD output - for your com- GREENBANK 67 TEMPUS 93 puter, alarm. etc., receives Rugby time signals, GREENWELD 47 TK ELECTRONICS 55 1000Km range, now get ABSOLUTE TIME, E49.80. GMT ELECTRONICS 62 TOOLRANGE LTD. 46 80KHZ RUGBY RECEIVER, as in MSF Clock, serial HAPPY MEMORIES 56 TRANSAM COMPONENTS 31 data output, built-in antenna, £13.70. HENRY'S RADIO 30, 36, 61 & 94 T&T ELECTRONICS 46 Each fun -to -build kit includes all parts, printed circuit, ILP ELECTRONICS 110 & 111 VIDEOTONE LTD. 7 case, instructions, postage, etc., money -back assurance INTERFACE COMPONENTS 66 WATFORD ELECTRONICS 4 & 5 so SEND off NOW. JAYEN DEVELOPMENTS 56 WEST HYDE DEVELOPMENTS 106 CAMBRIDGE KITS KEELMORE LTD 102 WILMSLOW AUDIO 76 45 (TG) Old School Lane, Milton, Cambridge KODE SERVICES 5 A Surplus & Ex Equipment Clearance Offer! XZ80 usersimill NEW QUALITY STEREOAMP CHASSIS Z7/ 60w. (RMS) protected 90w. plastic outputs. Low-cost plug-in memory cards LOGIC MONITORS Controls + selector, all din. sockets, smooth- available. Clip on to 14 or 16 put TTL IC ing, Heatsinking, 12/50v. wkg. NOW: 1K £29.95 to show al logic states Tested + data £9.95 inc. (leaflet sae). Fully buffered: equvalent to 2K £39.95 K. Lawrence, 1 1 low -power Schottky load Regent Road, Ilkley, W. Yorks. 3K £49.95 Uses circuit power supply or a separate 5V 03A PSU Our cards come ready built/tested. Only E24-50 including Orb TI -57, 58, 59 GAME SOFTWARE! Inc. Prices fully inclusive. 4:64/ 0s2 CMOS/TTL "Meltdown Syndrome'',Lunalander," Fruit Dept. ZX model only f 27-40 etc p&p Machine + Nudge," etc. Write P. J. Lynch, J. E. SINCLARE &Co 48 Coleridge Cres., Worthing, Sussex. For FLAIR MARKETING CO. 139A Sloane Street 9 Park Hill Road DS 1 free catalogue inc. SAE. London SW1X SAY The Arbours, Northampton COURSES ELECTRONIC SYSTEMS. Advanced level G.C.E.? Join the sixth form at South East London School. Mornington Road, London SE8 4BL. Full range advanced level courses 44,4 COURSES IN available. Details 01-692 1803. C,k° ELECTRONICS EXTENSIVE COURSES IN BASIC BSc IN ELECTRONIC ENGINEERING AND A four-year part-time degree course for mature students. Of particular interest to those engaged in Digital, Telecommunications or Central PASCAL Systems. Entry qualification required is an HNC or equivalent in including hands on mini -computer opera- Electrical and Electronic Engineering or Applied Physics. This CNAA tion These intensive courses are intended to degree is considered by the Council of Engineering Institutions as instruct from minimal knowledge to an meeting their C. Eng. academic requirements. operational capability of computer pro- gramming. CEI PART II Courses are fully residential, allowing maximum time for instruction and pro- One year full-time or two years' part-time course in preparation for the gramming. CEI Part II examination which is the present academic qualification for BASIC - Weekends from Friday Evening Chartered Engineers. Subjects offered include Electronics, Com- to Sunday Afternoon. munication, Central and Computer Engineering. Entrants should have PASCAL - Weekdays Monday Morning passed CEI Part I or have been exempted; holders of HNC and to Friday Afternoon inclusive. endorsements of HND are so qualified. For further details, dates available, fees Further details and application forms are available from the Informa- Phone (0401) 43139, or write CLEVELAND BUSINESS SERVICES tion Office, Room G219, Cambridgeshire College of Arts and Techno- (Dept. ETI-2), Cleveland House logy, Cambridge CBI 2AJ. Telephone (0223) 63271. Routh, North Humberside HU17 9SR 1 1 4 ETI JULY 1980 ELJORNOEPBEO'SAFRADSTCEOSMTPSUETLELIRNG LOMPUKIT UK101 * 6502 based system - best value for money on the market. * Powerful 8K Basic - Fastest around * Full Qwerty Keyboard * 4K RAM Expandable to 8K on board. * Power supply and RF Modulator on board. * No Extras needed - Plug-in and go. * Kansas City Tape Interface on board. * Free Sampler Tape including powerful Dissassembler and Monitor with each Kit. * If you want to learn about Micros, but didn't know which machine to buy then this is the machine for you. AVAILABLE READY Build. Understand and Program KIT ONLY E199 + VAT ASSEMBLED Et TESTED your own Computer for NO EXTRAS NEEDED only a small outlay READY TO GO FOR UN + VAT Specially designed case for Compir orange/ bla 6502 Assemb er/Edi-.or tor Compukit E1490 v With room for accessories 12).50 VAT nt 14X. The Compukit UK101 comes in kit form with all the parts necessary to be up and working, supplied. No extras are needed. Ater plugging in just press the reset keys and the whole world of computing is at your fingertips. Should you wish to work in the machine code of the 6502 then just press the M key and the machine will be ready to execute your NEW MONITOR FOR commands and programs. By pressing the C key the world of Basic is open to you. COMPUKIT UK101 In 2K Eprom 2716 This machine is ideal to the computing student or Maths student, ideal to teach your children arithmetic, and is also great Allows screen editing Saves data on tape fun to use. ...\111 Flashing cursor Text scrolls down £22.00 VAT Because of the enormous volume of users of this kit we are able to offer a new rscluced price of Elle + VAT 8MHz Super Quality Modulators £4.90 NASCOM-2 MICRO- only £356 6MHz Standard Modulators £2.90 , COMPUTER C12 Computer Grade Cassettes 10 for E4.00 only £305 VAT Super Multi -rail P S.U. +5 -5 + 12v 129.50 ii Anadex Printer Paper -2000 sheets 125.00 %411110 114111111111111111111111°S80LEVEL 216K1 THE ATARI VIDEO IOW COMPUTER SYSTEM Fully converted to UK T V Standard Comes complete with Neh.thFpEE 00 easy to follow manuals UK Power Supply- Cassette Leads Atari'sVideo Computer tie..et Sample tapes Special box to enable you to plug into your System now offers more than iwn TV Recommended for first lime buyers Just plug in 1300 different game variations SIP° 13 and go Ful Range of Software Available and optionsin twenty greet Your choice of freebies with Game Program cartridges' Have fun while you sharpen your every Nascom 2 purchased from us mental and physical coordination. NEW REDUCED - You can play rousing, challenging, either FREE POWER SUPPLY PRICES sophisticatedvideo games,the games that made Atari famous. OR FREE GRAPHICS ROM You'll havethrillafterthrill, 8K £449 . whether you're in the thick of a OR FREE VERO CASE TO dogfight, screechingaround a TAKE NASCOM 2 16K £549 VAT"4111111117;11114p11111, racetrack, or dodging asteroids in an alien galaxy. With crisp bright MicroprocessorsZ80A 8 bit CPU This will run at 4MHz 32K £649 colour Ion colour TV) and incredi- but is selectable between 1/2/4 MHz This CPU has now ble, true-to-lifesoundeffects. been generally accepted as the most powerful, 8 bit pro- With specialcircuitsto protect cessor on the market RRPfor 32K £795 The PEDIGRE PETS your TV. INTERFACE tyt. Cambium now available Keyboard New expanded57 keyLiconsolidstate Very popular for hone Er business use 8K Microsoft Basic in so - All at E13.90 each VAT keyboardespeciallybuiltforNascom Usesstandard ROM 8K Pet 32K b 16K with new improved keyboard SPACE Basic maths, Aimee Battle, Black Nascom, monitor controlled, decoding MI with green screen Jack,Breakout,Surround, T.V.The Iv peak to peak video signal can drive a monitor Extra ra,,eTh, ES Full rarvle of software available INVADERS Spacewar,VideoOlympics, directly and is also fed to the on -board modulator to drive CARTRIDGE Outlaw,Basketball,Hunt & the domestic T V E27.00 VAT Score, Space War, Sky Diver, Air 1.0.On -board UART(Int 64021 which providesserial Sea BattleCodebreaker, handlingfortheon bo4ldcassetteinterfaceorthe Ex -Stock Miniature Golf. RS232/20mA teletype interface F ,tr, Paddle Controllers Keyboard Controllers The cassette interface is Kansas City standard at either 300 video 100 or 1200 baud. This is a link option on the NASCOM-2. - E14.90 + VAT - E111.90 + VAT The RS232 and 20mA loop connector will interface directly 12" BLACK & WHITE into any standard teletype LOW COST VIDEO or,Tv GAME BREAK OUT The input and output sides of the UART are independently MONITOR .,,chable between any of the options - RRP £79 Has got to be one of the. tis possible to house input on the cassette and output the printer world's greatest TV games. I/O only £69 , VAT You really get hooked. As PIOThereisalsoatotally uncommittedParallel IMK38811 giving 16, programmable. I/O linesThese are featured in ETI. Has also 4 addressable as 2 x 8 bit ports with complete handshake Ideal for home, personarand business computer systems other pinball games and lots controls 12" diagonal vice° monitor Composite video input of options. Good kit for D ocumentationFull construction article is provided for Composite video input Compatible with many com- up -grading old amusement those who buy a kit and an extensive software manual is pro- puter systems Solid-state circuitry for a stable & sharp games vided for the monitor and Basic. picture Video baidwidth - 12MHz + 3DB Input im- B askThe Nascom 2 contains a full 8K Microsoft Basic in pedance -75 Ohms Resolution - 650 lines Minimum In MINI KIT - PCB, sound ft vision modulator, memory chip and de -code chip. Very simple to construct E14.90 + VAT one ROM chip with additional features like DESK, DOKE, Central 80% of CRT; 550 Lines Minimum beyond central OR PCB E2.90 MAIN LSI CM Both plus VAT SET, RESET for simple programming 80%. Please add VAT to all prices - Delivery at cost, will be advised at time of purchase. Please make cheques and postal orders payable to COMPSHOP LTD., or phone your order quoting CD BARCLAYCARD, ACCESS, DINERS CLUB or AMERICAN EXPRESS number. 1109.1.110,111 CREDIT FACILITIES ARRANGED - send S.A.E. for application form. *7 'at 14 Station Road, New Barnet, Hertfordshire, EN5 1QWTelex: 298755 TELCOM G MiN Telephone: 01.441 2922 (Sales) 01-449 6596 OPEN 10 am - 7 pm - Monday to Saturday COMPUTER "Europes Largest Discount Close to New Barnet BR Station - Moorgate Line. COMPCOMPONENTS Persons! Computer Store" * NOW in IRELAND at: 80 Marlborough St., Dublin 1. Tel: Dublin 749933 Part of the Compshop Ltd. Group) STEP INTO A NEW WORLD nni WHEN YOU DISCOVER II II IIIarpion For beginners or professionals, the Maplin catalogue will help you find just about everything you need for your project. Over 5,000 of the most useful components - from resistors to microprocessors - clearly described and illustrated. Send the coupon for your copy and STEP UP TO MAKIN SERVICE NOW A 1///!//I Post this coupon now for your copy of our 1979-80 catalogue price 70p. Please send me a copy of your 280 page catalogue. I enclose 70p (plus 46p p&p). IfI am not completely satisfied I may return the catalogue to you and have my money refunded. If you live outside the U.K. send £.1.35 or ten International Reply Coupons.I enclose £1.16. NAME ELECTRONICSUPPLIES LTD ADDRESS All mail to:- P.O. Box 3, Rayleigh, Essex SS6 8LR. Telephone: Southend (0702) 554155. 1 111,80 Shop: 284 London Road, Westcliff-on-Sea, Essex. (Closed on Monday). _-.,",-V.,...{.-7,------Telephone: Southend (0702) 554000. wow .. f/ I