Casio KP-C10 - PC Tag Writer Especificações

20002000Electronics For YouissuesIDEASPROJECTS&&EFYMore than 90 fully testedand ready-to-useelectronics circuits00VOLUME

CONSTRUCTIONFig. 5 (v)Fig. 5 (iv)vice uses the set-2 binary numbers foridentification of the collector (hence theemitter), the same number (base-Id) o

CIRCUIT IDEASsupply, diode D4 is reverse biased andacts as an ‘off’ switch, inhibitingthe conduction of diode D3, which al-lows normal functioning of

CIRCUIT IDEAS             S.C. DWIVEDIC.K. SUNITHThe circuit described her is dif-ferent form conventional doorbell circuits in the s

2000July

CONSTRUCTIONS.C. DWIVEDIBUILD YOUR OWN C-BANDSATELLITE TV RECEIVERSatellite TV reception has gainedmuch popularity in India overthe last three deca

CONSTRUCTIONreceives the signals from the satellite andfocuses them to the focal point where thefeed horn is positioned. The focused sig-nal picked u

CONSTRUCTIONAnother importantparameter of the LNB isits noise temperature.The noise equivalent tem-perature of most of thegood-quality LNBs rangesfrom

CONSTRUCTIONband from channel 2 to channel 12) tooperate the domestic receiver directly.The block diagram of a satellite re-ceiver is shown in Fig. 3(

CONSTRUCTIONwith the help of potmeter VR1 (audioB/W control) by changing the voltage atpin 2 (phase comparator section) of IC.Potmeter VR1 generally c

ELECTRONICS FOR YOU❚❚❚❚❚JULY 2000CONSTRUCTION50Fig. 7: Component layout for the PCB of Fig. 697

CONSTRUCTIONwith component side serving asa ground plane. From componentside, copper foil has been etchedfrom around all holes exceptthose connected t

CONSTRUCTIONPARTS LISTSemiconductors:IC1 - NE555, timerIC3 - CD4017, decade counter-de-coderIC3 - 7486, quad EX-OR gatesIC4,IC6,IC7 - MCT2E, optocoupl

CONSTRUCTIONEPROM-BASED PROGRAMMABLENUMBER LOCKMost of the code lock/number lockcircuits presented in EFY so farhave been based on discreteTTL and/or

111CONSTRUCTIONgrounded in this circuit. With eachclock pulse from IC1, the counter IC2 out-put increments by one and so alsothe address of EPROM. Sin

CONSTRUCTIONally via IC5 with the help of switches S1(marked zero) and S2 (marked one). A‘zero’ is entered by momentarily depress-ing switch S1 alone,

CIRCUIT IDEASCIRCUIT IDEASMost of the power-supply failureindicator circuits need a sepa-rate power-supply for them-selves. But the alarm circuitpres

CIRCUIT IDEASlector and emitter of the in-built transis-tor) is connected to the two terminals ofthe ‘=’ (of Casio FX-82LB used during actu-al testin

CIRCUIT IDEASin 1-volt steps. Dial II has ten resistors of1,100-ohm value each. This dial is markedfrom 0 to 0.9 volt in 0.1 volt steps. DialIII has

CIRCUIT IDEASerates approximately 1Hz waveform. Theoutput of IC1 serves as the clock inputfor the counter built around IC2 and IC3.The circuit can be

CIRCUIT IDEASsuccessive overloads. Under this condition,the system has to be manually reset. (Suc-cessive overload condition indicates thatthe invert

CIRCUIT IDEAStive half cycles and off-period of ring sig-nal. Once the handset is picked up, therelays will still remain energised becauseof low-impe

2000August

CONSTRUCTION2087 E607 ANI 07H Checks only first three bits2089 EAA021 JPE ERR If 2 bits are at logic-1 jumps to 21A0208C 326C21 STA 216CH Store the No

CONSTRUCTIONFor displaying text of Hindi, En-glish, or any other Indian languageon a TV-like screen, as may berequired for public announcements or for

CONSTRUCTIONour other Indian languages, we cannotmanage to use even a simple font withinthis 8 x 8 matrix (which needs one byteper line or 8 bytes per

CONSTRUCTIONThe character generator is just a listof dots for the characters in an order. Itdoes not necessarily require any hard-ware. Though such a

CONSTRUCTIONjust as in ‘d’,with 64 beingthe code. Thetable low-ad-dress is also10 64 and thehigh addressequals 10 64+ 80, and soon. Further,we need no

CONSTRUCTIONTABLE I: ASCII Key Codes for English, Hindi, and Tamil languages124

CONSTRUCTIONdim C(3,2048),ad(3,257),d(12),q(8)open “chtamil2” for random as #1 len=1field #1, 1 as A$clstotal%= LOf(1)for lan%=1 to 3for i%= 0 to 255

CONSTRUCTIONThis involves a simple 8085 micropro-cessor and an additional CRT controller.The dedicated CRT controller chip 6845has been popular ever s

CONSTRUCTION8085 µP-KIT BASEDSIMPLE IC TESTERS. RAJKUMARRUPANJANAAll electronic laboratories in engi-neering colleges and other insti-tutions need a d

CONSTRUCTIONtive locations for each IC, for every com-bination of inputs. If actual data read tal-lies with the stored data for all combina-tions of i

CONSTRUCTION927E 0C INR C ; NEXT INPUT COMBINATION927F 79 MOV A,C9280 FE02 CPI 02H ; CHECK IF ALL INPUT COMBINATIONS

CONSTRUCTION210B D383 OUT 83H 74373s. (no data would move to O/Ps)210D 7E MOV A,M Moves the 1st char. Of the datapointed, to the accumulator (mem.addr

130CONSTRUCTION9380 31FF9F GOOD1:LXI SP,9FFFH9383 211094 LXI H,9410H9386 3E00 MVI A,00H9388 0600 MVI B,00H938A CD160B CALL OUTPT

CIRCUIT IDEASCIRCUIT IDEASS.C. DWIVEDIDHURJATI SINHALOW-COST PCO BILLING METERThe circuit presented here can beused in PCOs for displaying theactual

CIRCUIT IDEASFig. 1 shows a muting circuit, whichmakes use of IC LB1403. Sig-nal from any pre-amplifier, such as HA1032,LA3161, or LA3160, is con-nec

CIRCUIT IDEASchange line to telephone2, the person at tele-phone 1 may inform theperson at telephone 2 (inthe intercom mode) thathe is going tochange

CIRCUIT IDEAStransistor T2. The transistor T2 will beenabled only when the charging capaci-tor raises its base potential to overcomethe reverse bias

2000September

CONSTRUCTIONThe 6845 is a programmable CRTcontroller, which can be pro-grammed so as to generate a ras-ter with the desired number of horizontaland ve

CONSTRUCTIONeach) and then coupling it to the base oftransistor BC148B to invert the sync sig-nals at its collector.The video signal is the dot patter

CONSTRUCTIONare extended by buffer IC 74LS244 to theRAM high address lines if CS1 is low. IfCS1 goes high, the buffer is tri-stated atits output, allo

139CONSTRUCTIONEPROM.2. Since 12 horizontal dots per char-acter are insufficient for an Indian lan-guage, a 12 x 12 matrix is chosen, thoughEnglish ap

CONSTRUCTIONThe analogue technology is givingway to the digital technology asthe latter offers numerous advan-tages. Digital signals are not only free

CONSTRUCTIONspace-moving characters in the standardtypewriters of the Indian languages. Par-ticularly in Hindi, there are multiplehooks, such as in ‘h

CONSTRUCTIONAddr. Code Label Mneumonics Remarks0000 .ORG 0000H26 11 LINE_NUMB: EQU 1126H28 11 ROW_NUMB: EQU 1128H29 11 CHAR_NUMB: EQU 1129H25 11 NI

CONSTRUCTION0168 47 MOV B,A ;Save in B0169 1A LDAX D ;Read video RAM016A E6 0F ANI 0FH016C B0 ORA B016D 12 STAX D ;store in video RAM (only alter left

CONSTRUCTION0294 DA A5 02 JC RIG_NIB ;if flag set go to start writing from rightnible;LEFT NIBBLE ROUTINE0297 3E FF LEFT_NIB:MVI A,FFH0299 13 INX D029

CONSTRUCTION03CA 3A 29 11 THIRL: LDA CHAR_NUMB03CD CD 29 11 CALL CHAR_NUMB03D0 5F MOV E,A03D1 16 14 MVI D,14H03D3 3A 28 11 LDA ROW_NUMB03D6 17 RAL03D7

CONSTRUCTION04F1 77 MOV M,A04F2 04 INR B04F3 13 INX D04F4 78 MOV A,B04F5 FE 10 CPI 10H04F7 C2 EB 04 JNZ IP04FA C9 RET04FB 55 40 46 09 TABL .DB 55H,40

CONSTRUCTIONDIGITAL CODE LOCKAversatile digital code lock circuitis presented here, which can haveup to 32-digit long secret code.The length of the se

CONSTRUCTIONlighting of LED1 via Schmitt NAND gatesN7, N5, and N6 to provide audio-visualindication to the effect that the data cor-responding to the

148CONSTRUCTIONdata corre-sponding toeach depres-sion of key iswritten into se-quential loca-tions of the se-lected page/pagesOperate/verify mode.In o

149CONSTRUCTIONincremented automatically whenever apressed key is released (as during regis-ter operation). If the data entered viakeyboard is found

CONSTRUCTIONMPEG card to the audio/video input of TVvia jacks J7 and J11 respectively. Useonly shielded wires for these connections.●Check to ensure t

CIRCUIT IDEASCIRCUIT IDEASDotmatrix display is suitable fordisplaying alphanumeric charac-ters and symbols. Dedicateddotmatrix display driver ICs are

CIRCUIT IDEAScounter ICCD4060, re-petitivelyoutputtingthe requiredbit pattern,correspond-ing to bit pat-tern for ‘Z’ inthis case.Let ussee how the bi

CIRCUIT IDEASDuring summer nights, the tem-perature is initially quite high.As time passes, the temperaturestarts dropping. Also, after a person fall

CIRCUIT IDEASfan run at the three speeds for anequal amount of time by connectingthree decimal decoded outputs of IC3to each of the transistors T1 to

CIRCUIT IDEAStion, using presets VR3 and VR4. For elec-tronic loads such as TV and VCR, the on-time delay may be set for 10 seconds to 20seconds. For

CIRCUIT IDEASThe logic signals to step, run, andhalt a computer or other appro-priate digital devices or systemmay be generated by this circuit, whic

2000October

CONSTRUCTIONS.C. DWIVEDIMOSFET-BASED 50HzSINEWAVE UPS-CUM-EPSinterruption in operation of a computeror continuity of the play mode of a VCRand TV is

CONSTRUCTION7473, which pro-duces the two50Hz square-wave outputs atits pins 8 and 9with a phase dif-ference of 180degrees betweenthe two. One ofthe o

CONSTRUCTIONshown in the circuit. Drains ofMOSEFTs of one bank are con-nected to one extreme tapingof 9-volt primary of the in-verter transformer X1,

CONSTRUCTIONput (AV in) facility in their TV, can makeuse of a pre-assembled audio-video to RFconverter (modulator) module of 48.25MHzor 55.25 MHz (ch

CONSTRUCTIONand capacitor C2 on the secondary sideact as filter/resonant circuit (at 50 Hz) toproduce a waveform approaching asinewave. LED1, when ‘on

CONSTRUCTIONinverting terminal voltage of the compara-tor IC5(a) above and below the referencevoltage of 5.1V. Similarly, non-invertinginput of the co

CONSTRUCTIONwhile the comparator circuit is identicalto over-voltage comparator. And hence,no separate explanation is required to beincluded. The outp

CONSTRUCTIONtransformer of 32-amp primary rating, thepower of the UPS-cum-EPS can be in-creased to 500 watts or 625 VA.The transformer ratings as ment

CONSTRUCTIONR-2R D/A CONVERTER-BASEDFUNCTION GENERATOR USINGPIC16C84 MICROCONTROLLERPRASANNA WAICHALS.C. DWIVEDIDigital to analogue conversion

165CONSTRUCTIONFig. 5: PIC16C84-based R-2R DACFig. 6: Actual-size single-sided PCB layout forthe schematic diagram of Fig. 5TABLE ICost comparison bet

CONSTRUCTIONThe low-cost R-2R ladder-type DAC(Fig. 2) requires no power supply at all,nor any active components such as buff-ers, op-amps, and storage

CONSTRUCTIONThe 8-bit port-B of this device hasbeen used as an output port, which isdirectly connected to the DAC. The 5-bitport-A has been used both

CONSTRUCTIONERRORLEVEL –302INCLUEDE <P16C84.INC>PCL equ 0x02 ;STATUS equ 0x03 ;FSR equ 0x04 ;PORT_A equ 0x05 ;PORT_B equ 0x06 ;EEDATA equ 0x08 ;

CIRCUIT IDEASCIRCUIT IDEASThe SMPS described here is suit-able for high-wattage stereos andother similar equipment. The cir-cuit employs two high-volt

CONSTRUCTIONserved that frequently, the picture/frames froze on the CTV screen and thepower to the MPEG converter card had tobe switched off and on

‘bUSY’. The last two displays are not used in theword ‘bUSY’. Rails ‘A’ and ‘B’ are active low for thecommon-anode displays used here. Segments that

CIRCUIT IDEAS‘low’ orviceversa).The out-puts offlip-flopsdrive thecorre-spondingrelays, inconjunc-tion with the four relay driver transistorsSL100. Th

sion of switch S1 up to the count 101.When switch S1 is depressed once again,normally the counter should read 110. Butthe two most significant bits o

CIRCUIT IDEASTELEPHONE RINGERUSING TIMER ICsPRABHASH K.P.RUPANJANAfor the ringing to start after the switch isclosed. The circuit used also has a prov

2000November

CONSTRUCTIONRUPANJANAPC-TO-PC COMMUNICATIONUSING INFRARED/LASER BEAMK.S. SANKARSerial communication between twoPCs has been covered earlier tooin E

CONSTRUCTION2 (receiver pin) of 9-pin (or pin 3 of 25-pin) ‘D’ connec-tor used for theserial port in thePC, so that thedata may beread. The opticalsig

177CONSTRUCTIONwith the torch on the photodiode. LED1should flicker at the burst frequency rateof the transmitter. This proves that the IRsignals are

CONSTRUCTIONProgram Listing for PC-to-PC Communication in C/* PROGRAM FOR LASER / IR COMMUNI-CATION BETWEEN TWO PCs *//* by K.S.Sankar for EFY Nov/

CONSTRUCTION cprintf(“ Press any key to quit .”); getch(); main();} goto loop; } else if(!kbhit()) { st[flag] = inp(COM);/*Get

CIRCUIT IDEASCIRCUIT IDEASThis add-on device for telephonescan be connected in parallel to thetelephone instrument. The circuitprovides audio-visual

CONSTRUCTIONing corruption of the data. Finally, wesucceeded, after modification of the cir-cuit as shown in Fig. 3. We were able toflawlessly transfe

CONSTRUCTIONS.C. DWIVEDIMULTI-EFFECT CHASER LIGHTSUSING 8051 MICROCONTROLLERThe 8051 microcontroller, first de-veloped by Intel, finds many ap-plicati

182CONSTRUCTIONnected externally between pins 18 and 19.The crystal frequency should range be-tween 1 MHz and 16 MHz for proper func-tioning of the co

CONSTRUCTIONtal ‘D’latch74LS373.Thepurposeof using74LS373is to de-multi-plex theaddresslines and the data lines. Hence, afterde-multiplexing, AD0-AD7

CONSTRUCTION003F 01 DB 01H0040 11 DB 11H0041 22 DB 22H0042 44 DB 44H0043 88 DB 88H0044 44 DB 44H0045 22 DB 22H0046 11 DB 11H0047 33 DB 33H0048 77 DB 7

CIRCUIT IDEASS.C. DWIVEDINormally, chargers available inthe market do not have anysort of control except for a ro-tary switch that can select differe

CIRCUIT IDEASThe reference terminal of regulator(IC3) is kept at 3.9V using LED2, LED3,and diode D6 in the common lead of IC3to obtain the required r

CIRCUIT IDEAS‘zero cal’. Now increase mV input to 21.85(corresponding to 400oC). Then vary VR2till +out terminal is at 430mV (temp.+RT). This is ‘gai

CIRCUIT IDEAShence the melody generator UM66 (IC1)does not get any power supply and isthus off.When bell switch S1 is pushed(closed), the audio outpu

CIRCUIT IDEASsary drivegiven to triac-5. Similarly,when outputsQ6 throughQ9 becomehigh, triac-4through triac-1 go off oneby one andthe earlier litup

CIRCUIT IDEAStransistor T1. The reset keysare wired to set pins 6 and8 of each IC. (Power-on-resetcapacitor C1 has been addedat EFY during testing as

2000December

CONSTRUCTIONIn this innovative project, a simpleelectronic bell system using com-monly available ICs is presented foruse in educational institutes. Th

CONSTRUCTIONmon-cathode 7-segment displays,and a few passive components. Formore details of the digital clock, thereaders may consult ‘Car ClockModule

193CONSTRUCTIONtinue towork asusual andhence theaccuracyof the pe-riods isnot af-fected bythe ‘on’ and ‘off’ times of transistor T4.To count and displ

194CONSTRUCTIONcircuit gets auto-maticallyswitched off.Though theringing of belland display ofperiods dis-continue, thedigital clockcontinues towork a

CONSTRUCTIONSIMPLE TELEPHONE RECORDING/ANSWERING MACHINEB.B. MANOHARThis project is intended to provideyou with a simple recording andanswering machin

CONSTRUCTIONtransistor T1 is pulled ‘low’. This low-going pulse is coupled to trigger pin 2of timer NE555 (IC1) configured asmonostable (retriggerable

197CONSTRUCTIONaccomplished via relays RL1 - RL3 asfollows:1. The output of timer IC4 energisesrelay RL1. On energisation, con-tacts RL1(a) of this re

CONSTRUCTIONa minute, with the remaining two min-utes reserved for recording other-endsubscriber’s message (i.e. the tape inthe player will run blank

CIRCUIT IDEASThis circuit uses only one octal D-type latch, IC 74LS373, and someassociated circuitry to controleight different gadgets. To control mo

2000ContentsJANUARY 2000CONSTRUCTION PROJECTS1) MICROPROCESSOR-CONTROLLED TRANSISTOR LEAD IDENTIFIER ---------------------------------------------

CIRCUIT IDEASswitches to a high level whenthe door is opened. (See wave-form B in Fig. 2.) Thus, a low-to-high going voltage transi-tion is available

CIRCUIT IDEASof the feedback from Q0 to D0, point‘A’ remains high even after releasingthe ‘off’ switch. As a result, relayRL1 is deactivated and LED

CIRCUIT IDEASS.C. DWIVEDIlevel. At power-on,the output ofNAND gate N2goes low. This isthe default state ofthe gate. The out-put of gate N2 goeslow (i

CIRCUIT IDEAScontain some residual carrier. This isknown as carrier leakage. By adjustingthe 100-ohm preset (VR2) and trimmer(C7) you can anull the s

CIRCUIT IDEASaccuracy, which is quite reasonable andadequate for some practical applications.The bulb (which is 230V, 100W, fila-ment type) shown in

CIRCUIT IDEASThe functions of the various pins aregiven in Table I. Pins 2 through 9 aredata pins. Here, we will use data pins 2to 5, corresponding t

The End

CIRCUIT IDEASsumption is extremely low. This makes itpossible to power the circuit from a bat-tery. The input sensing current throughthe fluid (with

CIRCUIT IDEASfew seconds. The program (software) anddata used for the purpose are given be-low in mnemonic and machine code forms.The program is self

CIRCUIT IDEASRUPANJANAAddress OP CODE LABEL Mnemonic Comments21 CD C3 09 21 JMP AA Repeat for next periodDELAY SUBROUTINE25 00 1B NEXT DCX D25 01 7A

February2000

CONSTRUCTIONPC BASED SPEEDMONITORING SYSTEMThis project describes the softwareand hardware necessary to moni-tor and capture in real time thespeed of

CONSTRUCTION1. Speed monitor and capture mod-ule. This module is used to monitor thespeed and store the data in a user-de-fined file.(a) The module fi

CONSTRUCTION#include<conio.h>#include<iostream.h>#include<graphics.h>#include<dos.h>#include<stdio.h>#include<time.h&

CONSTRUCTION s=inp(0x379);t=s;while(s==t)s=inp(0x379);break; default:textcolor(YELLOW+BLINK);cprintf (“Trigger mode: Manual ..Press any key to

CONSTRUCTIONcleardevice();setbkcolor(LIGHTGREEN);setcolor(RED);moveto(150,200);outtext(“Exiting to DOS..”);delay(2000);closegraph();exit(1);}//Display

2000ContentsMAY 2000CONSTRUCTION PROJECTS1) DIGITAL NUMBER SHOOTING GAME -------------------------------------------------------------------------

CONSTRUCTIONG.S. SAGOOAn electronics hobbyist always findspleasure in listening to a songfrom a cassette player assembledwith his own hands. Here are

CONSTRUCTIONand 13) ofCD4066, asshown inFig. 3, ismade high,it can switchAC and/orDC signalsbetween itscorrespond-ing outputpins (3-4, 8-9, 10-11, and

CONSTRUCTIONVR3 and VR4. But the mid-range frequency compo-nents get attenuated dueto capacitor C41 (0.047µF).In the hi-fi mode (Q1output of IC7 high)

33CONSTRUCTIONFig. 7. Actual-size, single-sided PCB for stereo cassette playerFig. 8. Component layout for the PCB

CONSTRUCTIONtact with terminal 3 (Q3 output of IC7high), normal gain is provided for thehigh-frequency components (treble) andhigher gain is availabl

CIRCUIT IDEASCIRCUIT IDEASVIVEK SHUKLABASS AND TREBLE FORSTEREO SYSTEMModern audio frequency amplifi-ers provide flat frequency re-sponse over the w

CIRCUIT IDEASG.S. SAGOOThis digital water level meter showsup to 65 discrete water levels inthe overhead tank (OHT). Thishelps to know the quantity

CIRCUIT IDEASso the displays (DIS.1 and DIS.2) remainoff. However, at the end of positive pulseat pin 1 of IC1 (and base of transistor T1),the freque

CIRCUIT IDEAScurrent converter. The design procedureis as follows:Calculate RI according to the applica-tion from one of the following equations:(a)

CIRCUIT IDEASMT2, i.e. connect MT1 to the negativeand MT2 to the positive side. For a goodworking triac, S2 would not initiate con-duction in the tr

2000ContentsSEPTEMBER 2000CONSTRUCTION PROJECTS1) DISPLAY SCHEMES FOR INDIAN LANGUAGESPART II (Hardware and Software) --------------------

March2000

CONSTRUCTIONRUPANJANARESONANCE TYPE L-C METERThe voltage developed across a ca-pacitor or an inductor in a series-resonant LCR circuit reaches itsmaxi

CONSTRUCTIONThe formulae (1) to (3) are based onthe assumption that there would be nomutual inductive coupling between thework-coil and the coil under

CONSTRUCTION43sistor T3), it would show a dip in the in-tensity of the LED, as the resonant cir-cuit is tuned to a peak.Positive 9V supply, for the me

CONSTRUCTIONof LED D5, or peak on the meter. Theintensity of LED D5, or the deflection ofthe meter pointer, would be the maxi-mum at resonance. If no

CONSTRUCTIONRUPANJANAELECTROLYSIS-PROOF COMPLETEWATER-LEVEL SOLUTIONOne major problem in using wa-ter as a conducting mediumarises due to the proces

CONSTRUCTIONused as protection diodes.The under- and over-voltage cut-off section (Fig. 1). It comprises a dualcomparator, two pnp transistors, and af

47CONSTRUCTIONFig. 3: Actual-size, single-sided PCB layout for the circuit shown in Figs 1 and 2Fig. 4: Component layout for the PCBhigh and resets IC

CONSTRUCTIONafter taking appropriate remedial actionsuch as filling the foot-valve of the motorwith water or by removing the air-lockinside the pipe.R

CIRCUIT IDEASPENDULUM DISPLAYCIRCUIT IDEASThe circuit presented here can beused for producing eye-catchingeffects like ‘pendulum’ and ‘dash-ing light

January2000

CIRCUIT IDEASpin connected to the invert-ing terminal of a compara-tor inside the IC) is notgrounded via a capacitor,but the potential at this pinis

CIRCUIT IDEASUsually rain-alarms employ asingle sensor. A serious draw-back of this type of sensor isthat even if a single drop of water fallson the

CIRCUIT IDEASS.C. DWIVEDILASER CONTROLLED ON/OFF SWITCHDr K.P. RAOThis circuit is built around a 555timer using very few compo-nents. Since the circu

CIRCUIT IDEAScauses transistor T2 to cut offand relay RL1 is not energised.When the telephone handsetis lifted, the voltage across pointsX and Y fall

CIRCUIT IDEASwarded by the author, the transformersX1, X2, and X3 primaries as well asswitch S1 were connected after the con-tacts of contactor. As a

April2000

CONSTRUCTIONSMART CLAP SWITCHLOKESH KUMATHCircuit of a smart clap switch, in-corporating certain unique fea-tures, is presented here. It over-comes th

CONSTRUCTIONgoes from ‘low’ to‘high’, it acts asa clock (CLK1)for first sectionof IC3. As a re-sult Q1 of theIC3 goes ‘low’ totrigger IC4,which produc

CONSTRUCTION58allotted 3.5-second time, the output of IC5becomes 0100 and the connected deviceturns ‘on’. At this stage, the parallel in-put is 0100 a

CONSTRUCTIONRUPANJANANow-a-days electronic voting ma-chines are being used effectively.The confidence of the voter inits flawless working is gradually

CONSTRUCTIONARUP KUMAR SENTABLE IOrientation Test socket Test socket Test socket Base-Id Base-Id Collector-Id forNo. terminal 3 terminal 2 terminal 1

CONSTRUCTIONFig. 1: Schematic diagram of the electronic voting machine.60

CONSTRUCTIONher vote.)7. Now, the voter cancast his/her vote by press-ing the appropriate key-board switch allocated tothe candidate of his/herchoice.

CONSTRUCTION62Fig. 3: Actual-size, single-sided PCB layout for the circuitFig. 4: Component layout for the PCB

CONSTRUCTIONaccepting any further vote. Thus, the maxi-mum number of votes that can be regis-tered against any one candidate shouldnot exceed 9999. Th

CONSTRUCTIONwww.electronicsforu.coma portal dedicated to electronics enthusiastsAddress Opcode Mnemonics CommentsCount subroutine00B6 31 FF 80 LXI SP,

CIRCUIT IDEASS.C. DWIVEDIWATER-TANK LEVEL METERCIRCUIT IDEASM.K. CHANDRA MOULEESWARANThe water-tank level meter de-scribed here is very simple anduse

CIRCUIT IDEASboard, in a single line, so that they maybe pushed through the cutouts in the frontpanel of the enclosure from inside.The water level at

CIRCUIT IDEASS.C. DWIVEDIIn this circuit, a simple calculator, inconjunction with a COB (chip-on-board) from an analogue quartzclock, is used to make

CIRCUIT IDEASrent local call meter reading will blinkonce every second.In prototype circuit, the author usedTAKSUN calculator that costs around Rs80.

CIRCUIT IDEASThe latch-up alarm described hereis based on single IC NE555,configured as an astablemultivibrator. The timing components areselected su

CONSTRUCTIONFig. 1: Schematic circuit diagram of the transistor lead identifiertions. As a result, the LEDs con-nected to the collector and emit-ter l

CIRCUIT IDEASS2 (PLAYL). Pressing(grounding) this pin ends thepower-down mode and ini-tiates the play cycle. Thestored/recorded message isplayed unti

2000May

CONSTRUCTIONDIGITAL NUMBERSHOOTING GAMEMany electronic video games areavailable in the market. Butfor those who may prefer to as-semble the game the

CONSTRUCTIONfrequency (of the order of 1 Hz to 4 Hz).Its frequency can be varied with the helpof potentiometer VR1.For proper functioning of CD4033 an

CONSTRUCTION74reset pin 4.During the low-level period of gateN3, output of gate N4 is ‘high’ and theflip-flop (IC4) is in the reset state. Ifany one o

CONSTRUCTIONSounds of various kinds have alwaysfascinated human beings. Many de-vices have been invented for re-cording and playing back the sounds—fr

CONSTRUCTION76At frequnecies higher than f2 (f>f2,high end of audio range), capacitorsC2 and C3 overcome the effect of potenti-ometer VR1. As C2 an

CONSTRUCTIONFrom byte Number Informationof bytesRIFF chunk:0 4 Contains the characters ‘RIFF’4 4 Size of the RIFF chunkWAVE chunk:0 4 Contains the cha

CONSTRUCTIONstrcpy(&(Menu[MNU_FILE].Tip[1][0]),“Save as a *.wav file”);strcpy(&(M

CONSTRUCTIONRemoveMenu(MenuID);return(0);}else{if(prevMenu!=NONE){RemoveMenu(MenuID);return(ShowMenu(prevMenu));}}break;case RIGHT_ARROW:if(subMenu[Cu

CONSTRUCTIONFig. 2: Effective biasing of PNP transistors using set 1 binary numbersFig. 3: Effective biasing of NPN transistors using set 2 binary num

CONSTRUCTIONvoid SetEnvVariables(){}void SaveFile(){}void main(){int ch;textbackground(BLACK);textcolor(LIGHTGRAY);clrscr();_setcursortype(_NOCURSOR);

CONSTRUCTION OUTPUT;dlen=NoSamples;BOOL bits16=FALSE;if(wave.fmt.FormatSpecific==BITS16) bits16=

CIRCUIT IDEASS.C. DWIVEDISTEPPER MOTOR DRIVERCIRCUIT IDEASPIYUSH P. TAILORStepper motors are widely usedwhere precision and accuracy arethe primary c

CIRCUIT IDEASTachometer is nothing but a simpleelectronic digital transducer. Itfinds many applications in ourday-to-day life.Normally, a tachometer

CIRCUIT IDEASused for the entire circuit. The circuitshown in Fig. 2 employs 7805 regulator.This 4-digit counter can be readily inter-faced to many c

CIRCUIT IDEASS.C. DWIVEDISCRs and Triacs are extensivelyused in modern electronic powercontrollers—in which power is con-trolled by means of phase an

CIRCUIT IDEASquartz clocks and is readilyavailable in the market. But useof a 1kHz crystal using a quad-NAND IC CD4093 as clock gen-erator, as shown

2000June

CONSTRUCTIONPORTABLE OZONE GENERATORThis article is dedicated to thegood health of EFY readers inthe year 2000 and beyond. It de-scribes an ozone gene

CONSTRUCTION89Fig. 3: Actual-size, single-sided PCB layoutFig. 4: Component layout for the PCB

CONSTRUCTIONFig. 4: Schematic circuit of special display system(i)Fig. 5: Flowcharts for the main program and various subroutines(ii)(iii)1. Q1 (logi

CONSTRUCTIONis more efficient and silent in its dis-charge. One can easily assemble this por-table ozone generator in a plasticbreadbox (used for stor

CONSTRUCTIONcircuit has a high-voltage winding forthe EHT of the picture tube. This EHT isconnected to the electrode (aluminiumfoil) of the ozone disc

CONSTRUCTIONof the LOT winding, in place of the mainsrectified 200V DC, as shown in Fig. 2.For testing, one is not required to use230V directly at all

CONSTRUCTIONBut now this connection is removed andonly the pump is made to work.The end of the aquarium air-pump,which produces air under pressure, is

CONSTRUCTIONCONFERENCE TIMERS.C. DWIVEDIK. UDHAYA KUMARAN VU3GTHtactile switches S2 and S3, with slideswitch S1 in 'set' position. Once the

CONSTRUCTION95operation, this pulse (one-per-minute)is simultaneously applied to pin 15 ofIC3 and IC4 through switch S1 (in startposition), and diodes

CONSTRUCTIONmay be. Due to conduction of diode D7,transistor T2 will be ‘on’ state and thusbinary counter (IC5) is in runingcondingion. At the same ti

CIRCUIT IDEASADD-ON STEREO CHANNELSELECTORCIRCUIT IDEASPRABHASH K.P.RUPANJANAThe add-on circuit presented hereis useful for stereo systems. Thiscircu

CIRCUIT IDEASing through the channels continues un-til it receives an audio signal exceedingthe preset threshold value. The skipswitch S1 is used to

CIRCUIT IDEASwhen surrounding temperature is 0digC. (To cater to resistance tolerances andcalibration, resistor R6 (22-ohm) and 1-kilo-ohm preset VR1