HP-AC-4A-4B-Manual 电路图.pdf
HP Archive This vintage Hewlett Packard document was preserved and distributed by Pleasevisituson the web! Scanned by on-line curator: Tony Gerbic * For FREE Distribution Only * RadioFans.CN 收音机爱 好者资料库 OPERATINGANDSERVICINGMANUAL FOR MODELAC-4AAND AC-4B DECADECOUNTERS Copyright1955byHewlett-PackardCompany Theinformationcontainedinthisbooklet isintendedfortheoperationandmain- tenanceofHewlett-Packardequipmentand isnottobeusedotherwiseorreproduced withoutthewrittenconsentoftheHewlett- PackardCompany. HEWLETT-PACKARDCOMPANY 275PAGEMILLROAD,PALOALTO,CALIFORNIA,U.S.A. 0134ABOOl RadioFans.CN 收音机爱 好者资料库 NOTE ThismanualwaswrittenfortheAC-4ADecadeCounterbutalso appliestotheAC-4BDecadeCounter.Theappearanceandcircuit operationoftheAC-4AandtheAC-4Bareidentical;thedifferences intheAC-4Bareasfollows: 1)Upperfrequencylimitof220kc 2)Highercurrentrequirementof18milliamperes 3)Lowerinputpulserequirementofapprox.60voltspeak 4)Differentcomponentvalues(coveredinseparatepaJ:ts listandschematicdiagramfortheAC-4B) Exceptfortheinputvoltagerequirements(seespecifications)the AC-4BisdirectlyinterchangeablewiththeAC-4A.TheAC-4Bcan beusedinmostcasesforemergencyreplacementfortheAC-4Aor toincreasethemaximumcountingrateofcountersutilizingan AC-4Aintheunitsposition.However,itisnotrecommendedfor normalreplacementoftheAC-4A. RadioFans.CN 收音机爱 好者资料库 CountingRate Double-pulse Resolution InputVoltage OutputVoltage Reset StaircaseOutput Voltage PowerSupply Dimensions Mounting Weight SPECIFICATIONS AC-4A 120KC 80vnegativepulse withlsrisetime. (Les samplitudere- quiredwithfaster risetime.) 80vnegativepulse. ToZero-Openbase pinconnectionor applypositivepulse. ToNine-Apply negativepulse. +135vatcountof zero. +55vatcountof nine.10steps. 6.3vac10%at1.2a. +300vdcat15rna. 5-5/8deepx1-1/4 widex6-1/8high. Requiresoctal socket. Net1Ib;shipping, 21bs. AC-4B 220KC 4s 55vnegativepulse with1. 5srisetime. (Lessamplitudere- quiredwithfaster risetime.) 80vnegativepulse. ToZero-Openbase pinconnectionor applypositivepulse. ToNine-Apply negativepulse. +135vatcountof zero. +55vatcountof nine.10steps. 6.3vac10%at1.2a. +300vdcat15rna. 5-5/8deepx1-1/4 widex6-1/8high. Requiresoctal socket. Net11b;shipping, 21bs. SECTIONI GENERALDESCRIPTION 1-1DESCRIPTION TheModelAC-4ADecadeCounterisageneralpurpose,plug-in electroniccounterthatcountselectricalpulsesappliedtoitsin- putterminalandindicatesthenumberofthelastpulsereceived inacolumnofnumeralsfromAto9onthefrontpanel. TheAC-4Aproducesoneoutputpulseeachtimetheregistered countsstepsfrom9toa,i.e.,producesoneoutputpulsefor everyteninputpulses.Consequently,anydesiredcountstorage capacitycanbeobtainedbyconnectingtheunitsinseriesandby placingthemsidebysidesothatthefirstunitsprovidetheunits digit,thesecondunitprovidesthetensdigit,andsoon.The finalansweristhenreaddirectlyasanumberacrosstherowof counterunits. ThecountisindicatedonthepaneloftheAC-4Abyilluminating thecorrectnumeralinthenumbercolumnwithaneonlamp. Engravednumeralsandspecialreflectingsurfacesbehindthe neonlampsinsuregoodreadability. Asecondoutputsignal,theStaircaseoutput,isprovidedfor operatingcertaintypesofexternalindicatingdevices.Thisout- putsignalconsistsofnineequalstepsofvoltage,onestepfor eachcountindicatedinthenumbercolumn. TheAC-4Autilizesetchedcircuitswhichprovidegoodproduction uniformityandverylowcapacitywiringandresultinaverystable, fastcountingunit.Theopen-frameconstructionlowersoperating temperaturesandsimplifiespartsinspectionandservicing. TheAC-4Arequires300voltsdcatapproximately15milliamperes and6.3voltsacat1.2amperesforoperation,neithervoltage requiringregulation.Theunitplugsintoastandardoctalsocket andissecuredbyasinglemountingscrewatthetopofthenumber column. TheAC-4Aisdirectlyreplaceablewithanyotherplug-in-counter unitusedinHewlett-PackardElectronicCounterinstruments, andinaddition,itisalsodirectlyinterchangeablewithmany similardecadecounterunitsofothermanufacturers. -1- SECTIONII INSTALLATION 2-1SOCKETCONNECTIONS ThepinsontheoctalplugfortheAC-4Aarelistedbelowwith theirfunctions: Pin1 -Pins1and7receivefilaIl1entpower,6.3volts,10% 1.2aIl1peresandshouldnotcontaintransientpulses ofsufficientaIl1plitudetocauseerraticcounting. EithersideofthefilaIl1entcircuitIl1aybegrounded externally. Pin2 -Pin2providesforresettingtheAC-4AtoIIawhen anewcountistobestarted.FortheAC-4Atocount, thispinIl1ustbeconnectedtogroundthroughare- sistancenotIl10rethan750ohIl1s.ToresettheAC-4A toIIathiscircuitIl1aybeIl1oIl1entarilyopened,ora positivepulseof150voltspeakIl1aybeappliedtopin 2.(Seenote1.) DiagraIl1softypicalresetcircuitsareavailablefroIl1 theHewlett-PackardCOIl1panyuponrequest. Pin3 -Pin3providestheoutputsignal(inputsignal.;.10) froIl1theAC-4A.Theoutputconnectionisdirect- coupledandhasfroIl150to140voltd-cpotentialon it.Theoutputsignalisanegative-goingwavefroIl1 the140-voltleveltothe50-voltlevelwhichoccurs whentheunitpass e sthecountofII9Theload placedonpin3shouldnotbelessthan300,000ohIl1s, or6000ohIl1Sinserieswith100-l-lf.(SeeOUTPUT WAVEFORMinMaintenanceSection-page12.) Pin4 -Pin4receivesthed-coperatingpower,300-voltdc 10%atapproxiIl1ately15Il1illiaIl1peres.Thisvolt- agedoesnothavetoberegulated,butitIl1ustnot containtransientpulsesorrippleofsufficientaIl1- plitudetoproducerandomcounts. Pin5 -Pin5receivestheinputsignaltobecounted.The AC-4Acountsnegative-goingwavefrontshaving approxiIl1ately80voltspeakaIl1plitudeand1 Il1icro- secondrisetiIl1e.FasterrisetiIl1esdecreasethe aIl1plituderequired.(Seenote2.) -2- o . v- o o 0 I . -.D L) - N - Pin6 -.Pin6istheGroundandB -connectionandiscon- nectedtochassisorgroundbus. -Pin7 -Filamentcircuit,seePin1. Pin8 -Pin8providestheStaircaseoutputvoltage.The staircasevoltageisproportionaltothedigitdis- playedandmaybeusedtooperatearemoteindi- catingdevice.Theopencircuitvoltagevariesfrom +138voltsforadisplayedcountof0to+54volts foradisplayedcount9inapproximatelyequal steps.(SeeSTAIRCASEOUTPUTwaveformin Section4.) Thestaircaseoutputcircuithasaninternalimpeq- anceofapproximately700,000ohmsandtheoutput voltagedependsupontheexternalloadconnectedto thiscircuit.Theloadconnectedtothiscircuitdoes notaffectthenormalcountingoftheunit .-CAUTION-. Suitableprecautionsmustbetakentopreventcouplingtran- sientvoltagesthroughanyoftheexternalconnectionstothe AC-4A,orerraticcountingmayresult. NOTE1 ThedisplayedcountontheAC-4Amayberesetto0 manuallywitha switchorelectronicallybypuIse.ApuIse usedforresetmusthaveafastriseandslowdecay;pulse widthisunimportant.Therisetimemustbeapproximately oneIJ.sec15avoltsasappliedto750ohmsmaximumbe- tweenpin2andground.Theunitcanberesetto9witha negativeresetpulse. NOTE2 The-hp-AmplitudeDiscriminatorUnit,Model522B-58B generatesasuitabledrivingpulsefortheAC-4A,andhasa maximumsensitivityofO.2voltonanywaveform.Com- pletedetailsofthisplug-in-unitareavailablefromthe Hewlett-PackardCompany. -3- SECTIONIII THEORYOFOPERATION 3-1GENERAL TheAC-4ADecadeCounterplug-inunitconsistsoffourbi-stable multivibrators(binaries)andabankof10neonlightednumerals onthefrontpanel.Asthebinariessensetheinputpulses,certain combinationsofvoltagesaresetupbetweenhalvesofthebinaries whichlighttheappropriateneonlampforeachpulse. Thestateofthefirstbinarydetermineswhetheranoddoreven numberedlampwillbelightedbyapplyingonenecessaryvoltage totheevenlamps,ortotheoddlamps.Theothervoltageisob- tainedasthedifference-voltageexistingacrosstwospecifichalves oftwodifferentbinaries.Assubsequentinputpulsesarereceived thedifference-voltagelightingthelampsprocedesfromonepair ofbinariestothenext,lightingsubsequentlamps. Thefourbinariesareconnectedincascadesotheoutputfromthe firstisfedtotheinputofthesecond,andsoon.Eachbinaryis designedtorespondonlytonegative-goinginputpulses.Each binaryproducesalternatelypositiveandnegativeoutputpulsesfor aseriesofnegativeinputpulses.Sincethenextbinarysenses onlythenegativepulses,theeffectistodividebytwo. Withfoursuchbinaries16inputpulseswouldberequiredtoobtain onenegativeoutputpulse(overalldivisionwouldbe16).However, bytheuseoftwofeedbackloops6extracountsareaddedwithin theunitsothatonly10inputpuIsesarerequiredtoobtainonenega- tiveoutputpuIsetomakethetotaldivision10.Thefeedbackcir- cuitsusedincountersarenottobeconfusedwithfeedbackcircuits usedinamplifierdesign.Counterfeedbackcircuitsareusedonly toapplyapuIsefromoneofthebinariesinachaintoanotherin thesamechain.Ifthefeedbackpulseisofthecorrectpolarity,it willtriggerthebinary,producingthesameresultasadditional puIsesattheinput.Theactionofanindividualbinaryisdescribed belowfollowedbyadiscussionoftheoperationoffoursuchbinaries connectedinseries. 3-2THEBI-STABLEMULTIVIBRATOR,ORBINARY Thecircuitofatypicalbi-stablemultivibratorisshowninFigure1. Thiscircuithastwostablestates;one,withAsideconducting, two,withBsideconducting.Allinputpulsesareappliedequally toboththeAandBsides,however,onlynegativegoingpulses canstarttheswitchingaction. -4- o I- W o o 0 I I- : t300V C3 27 tf4V R26 lOOK R3 47K R5 270K +53V _-_-.OUTPUT t3fV C2 27 Cl INPUT27 I . I N o o I (f) . o Fig.1.CircuitofbinaryusedinAC-4ACounterUnit Priortoreceivinganinputpulseabinaryrestsinoneofitstwostable states;onesideisconducting,onesideisnot.Thehighpositivevolt- ageattheplateofthenon-conductingtubemaintainsahighchargeon thecouplingcapacitortothegridoftheconductingtube,whilethelow platevoltageontheconductingtubemaintainsonlyasmallchargeon thecapacitortothegridofthenon-conductingtube. AninputsignalisappliedtoapointintheplateloadresistorsatRl whichiscommontotheplateloadsofbothsidesofthebinary.This pulselowerstheplatevoltageofbothtubes,butlowerstheplatevolt- ageofthenon-conductingtubebyalmostthefullvalueoftheinputpulse, whereastheplatevoltageoftheconductingtubeisonlyslightlyaffected asitwasalreadyataverylowvalue.Consequently,thenegativeinput pulsecoupledfromtheplateofthenon-conductingtubetothegridofthe conductingtubewillbelarge;thenegativepulsecoupledfromtheplate oftheconductingtubetothegridofthenon-conductingtubewillbevery smallandisofnoimportance.Apositiveinputpulsefollowingthesame pathhasnoaffectuponthegridoftheconductingtubeandcausesno switchingaction. Thenegativeinputpulse,foraportionofitsduration,holdsbothsides ofthebinaryinastateofnon-conduction,andappliesahighnegative biastothegridofthepreviouslyconductingtube(essentiallyre- versingtherelativegridbiasforthetwohalvesofthebinary).Con- sequently,whentheinputpulseis.ended,thecapacitortothegridof thepreviouslynon-conductingstageandthehighplatevoltagetowhich itisnowconnectedcausethisgridtogopositiveveryquickly,before -5- theoppositecapacitorcanreturnfromitspotentialfarbeyondcutoff. Thebinaryhasthusreturnedtoastateoppositetothatwhichitheld priortoreceivingthenegativeinputpuIse. Astrong,sharpoutputpulseisobtainedfromoneplatecircuitand coupledtothenextbinary.TheoutputpuIseispositivewhentheout- puthalfofthebinaryisswitchedoutofconduction,andnegativewhen itisswitchedintoconduction.Theamplitudeoftheoutputpulses fromthe2nd,3rdand4thbinariesintheAC-4Aareequal,andshould beapproximately82volts(from+53to+135),whiletheoutputfrom the1stbinaryisapproximately110volts,(from+62to+172). 3-3OPERATIONOFFOURCACADEDBINARIES Theoperationoffourbinariesconnectedincascadeandtheoperation oftheneonlightingcircuitsisdescribedinthefollowingparagraphs withtheaidofthediagraminFigure2.Inthesediagrams,thewave- formsarethed-cpotentialattheoutputofeachbinary.Theactuating pulsethatisappliedtothenextbinaryconsistsoftheriseanddecay portionsofthewaveformshownduetobeingdifferentiatedbythe couplingcapacitor. DiagramAshowsthewaveformsobtainedfromasystemoffourbi- narieswithnofeedback.Thetoprowrepresentsthepulsesapplied totheinput,andeachsubsequentrowistheoutputofasucceeding binary.Waveformsareorientedinrelationtothefrequencyapplied totheinput.Readingfromlefttoright,eachdown-goinglineisa negativepulsewhichcausesthenextbinarytoswitchitsstate.Each up-goinglineinthewaveformisapositivepulseandiswithouteffect. Asshown,onepositiveoutputpulseisobtainedafter8inputpulses andonenegativeoutputpulseafter16inputpulses.Suchasystem wouldrequireacolumnof16numbersforthereadout,acomplexsys- terntoreadifmorethanonecounterisused. Amoreusefulindicatingsystem,0through9,canbeobtainedwhen thedivisionratioofthesetoffourbinariesismadetobe10insteadof 16.Thereadoutcanthenbeadirectreadingdecimalnumberwhen morethanonecounterunitisused,onebesidetheother.Tomakethe systemproduceoneoutputpulseforeveryteninputpulses(insteadof 16)theextrasixpulsesareeffectivelysuppliedinternallybyfeeding therequiredpulsesfromonebinarytoanother.DiagramBshows suchasysteminoperation.Twofeedbackpathsareused,thefirst oneretriggersthesecondbinaryandpositionsittwoinputpulses fartheralong.Thesecondfeedbackpathretriggersthethirdbinary andpositionsitfourinputpulsesfartheralong,thustheeffectofsix additionalinputpulsesisduplicatedwithintheunittomaketheunit dividebyten. DiagramCshowshowthereadoutof10neonlightednumbersaremade tolightintheirpropersequence.Asinputpulsesenter,theycause thefirstbinarytocontinuallyswitchfromonestatetotheother.One -6- : INPUTOUTPUT BINARY1 I -IVIAIVIB I BINARY2 I V2AIV2B I BINARY3 I V3AIV3B I BINARY4 I V4AIV4B-1k I INPUT (A) OUTPUT 2OUTPUT 3OUTPUT 4OUTPUT INPUTOUTPUT BINARY4BINARY3 I V2AIV2B I BINARY2 C-BFEEOBACK/-1.-_-+- l.-_-.J-o-cFEEOBACK BINARY1 I -tVIAIVIB I . I N o o I (f) . o INPUT (8) 1OUTPUT 2OUTPUT 3OUTPUT 4OUTPUT O-C+41Io-c,+4II _ -I./-i/-I._r-L BINARY1 +177V VIB VIA+IIOV +137V .+110 V (C) V2BV4BV2AV3BV3AV4BV2BV4AV2AV4A Fig.2.OutputWaveformsofEachBinaryina4-BinarySystem: (a)Withoutfeedbacktodivideby16 (b)Withfeedbacktodivideby10 (c)Thelightednumeralreadoutsystem -7- halfofthebinaryisconnectedtoonesideofalltheevennumbered lamps.Theotherhalfisconnectedtoonesideofalltheoddnum- beredlamps.Asthebinaryswitchesbackandforthitalternately suppliesoneneededvoltagetolighttheodd,thentheevennumbered lamps.Thedifferencevoltagethatdetermineswhichoddoreven lampislightedisobtainedfromcombinationsofthevarioushalves oftheremainingthreebinaries,andconsistsofaresultantvoltage whentwodifferentbinaryhalvesarecombined.Threeresultant voltagesarepossible:whenbothhalvesareconducting,whenboth halvesarenon-conductingandwhenoneisconductingandoneis not.Onlywhenbothhalvesareconductingandthevoltageisat itslowestisthevoltagedifferencebetweenthiscombinationand thatestablishedbytheinputbinarysufficienttolightaneon.This voltageofapproximately75voltsgraduallymovesdownthebank ofneonsshowninthediagramassucceedinginputpulsesswitch thebinariesandtheoddandevenlampsarealternatelygiventhe necessaryvoltage. -8- o . L.V o o 0 I . SECTIONIV SERVICINGTHEAC-4APLUG-INCOUNTERUNIT 4-1GENERAL Amajorityoffailuresincounterunitscanberemediedbytube replacement.Systematicallyreplaceonetubeatatimetoprevent maskingotherpossiblecircuitfailures.Ifatubeisreplacedwith- outimprovementinoperation,returntheoriginaltubetoitssocket. AnyAC-4ACountermaybeexchangedwithanyotherAC-4ACounter withoutadjustmentorchangeinoperation;thereforetodetermine ifacounterisfaulty,replaceitwithoneknowntobeoperating properly.Animprovementin
