基于-单片机数字电压表电路设计外文文献原稿和译文

外文文献原稿和译文外文文献原稿和译文原原稿FrontsideCopyrightofthiscircuitbelongstosmartkitelectronics.InthispagewewillusethiscircuittodiscussforimprovementsandwewillintroducesomechangesbasedonoriginalschematicGeneralDescriptionThisisaneasytobuild,butneverthelessveryaccurateandusefuldigitalvoltmeter.IthasbeendesignedasapanelmeterandcanbeusedinDCpowersuppliesoranywhereelseitisnecessarytohaveanaccurateindicationofthevoltagepresent.ThecircuitemploystheADC(AnaloguetoDigitalConverter)I.C.CL7107madebyINTERSIL.ThisICincorporatesina40pincaseallthecircuitrynecessarytoconvertananaloguesignaltodigitalandcandriveaseriesoffoursevensegmentLEDdisplaysdirectly.ThecircuitsbuiltintotheICareananaloguetodigitalconverter,aparator,aclock,adecoderandasevensegmentLEDdisplaydriver.ThecircuitasitisdescribedherecandisplayanyDCvoltageintherangeof0-1999Volts.TechnicalSpecifications-CharacteristicsSupplyVoltage:+/-5V(Symmetrical)Powerrequirements:200mA(maximum)Measuringrange:+/-0-1,999VDCinfourrangesAccuracy:0.1%FEATURESSmallsizeEasyconstruction1 / 13Lowcost.Simpleadjustment.Easytoreadfromadistance.Fewexternalponents.HowitWorksInordertounderstandtheprincipleofoperationofthecircuititisnecessarytoexplainhowtheADCICworks.ThisIChasthefollowingveryimportantfeatures:Greataccuracy.Itisnotaffectedbynoise.Noneedforasampleandholdcircuit.Ithasabuilt-inclock.Ithasnoneedforhighaccuracyexternalponents.Schematic(fixed16-11-09)2 / 137-segmentdisplaypinoutMAN6960AnAnaloguetoDigitalConverter,(ADCfromnowon)isbetterknownasadualslope converter or integrating converter. This type of converter is preferredoverothertypesasitoffersaccuracy,simplicityindesignandarelativeindifferencetonoisewhichmakesitveryreliable.Theoperationofthecircuitisbetterunderstoodifitisdescribedintwostages.Duringthefirststageandforagivenperiodtheinputvoltageisintegrated,andintheoutputoftheintegratorattheendofthisperiod,thereisavoltagewhichisdirectlyproportionaltotheinputvoltage. Atthe end ofthe preset period the integrator isfed with aninternalreferencevoltageandtheoutputofthecircuitisgraduallyreduceduntilitreachesthelevelofthezeroreferencevoltage.Thissecondphaseisknownasthenegativeslopeperiod anditsduration depends ontheoutputoftheintegrator inthefirstperiod.Asthedurationofthefirstoperationisfixedandthelengthofthesecondisvariableitispossibletoparethetwoandthiswaytheinputvoltageisinfactparedtotheinternalreferencevoltageandtheresultiscodedandissendtothedisplay.AllthissoundsquiteeasybutitisinfactaseriesofveryplexoperationswhichareallmadebytheADCICwiththehelpofafewexternalponentswhichareusedto configure the circuit for the job. Indetail the circuit works asfollows. voltagetobemeasuredisappliedacrosspoints1and2ofthecircuitandthroughthecircuitR3,R4andC4isfinallyappliedtopins30and31oftheIC.ThesearetheinputoftheICasyoucanseefromitsdiagram. (INHIGH&INLOWrespectively).3 / 13TheresistorR1togetherwithC1areusedtosetthefrequencyoftheinternaloscillator(clock)whichissetatabout48Hz.Atthisclockratethereareaboutthreedifferentreadingspersecond.ThecapacitorC2whichisconnectedbetweenpins33and34oftheIChasbeenselectedtopensatefortheerrorcausedbytheinternalreferencevoltageandalsokeepsthedisplaysteady.ThecapacitorC3andtheresistorR5aretogetherthecircuitthatdoestheintegrationoftheinputvoltageandatthesametimepreventanydivisionoftheinputvoltagemakingthecircuit faster andmorereliable asthepossibility oferrorisgreatly reduced. Thecapacitor C5forcestheinstrument todisplay zerowhenthereisnovoltage atinput. Theresistor R2together withP1areusedtoadjust theinstrument duringset-upsothatitdisplayszerowhenthe inputiszero.Theresistor R6controlsthecurrent that isallowed to flow through the displays sothat issufficientbrightnesswithoutdamagingthem.TheICaswehavealreadymentionedaboveiscapabletodrivefourmonanodeLEDdisplays. Thethreerightmostdisplaysareconnectedsothattheycandisplayallthenumbersfrom0to9whilethefirstfromtheleftcanonlydisplaythenumber1andwhenthevoltageisnegativethe «-«sign. The whole circuit operates from asymmetrical ρ5VDC supply which appliedatpins1(+5V),21(0V)and26(-5V)oftheIC.ConstructionFirst ofall let usconsider afew basics inbuilding electronic circuits onaprinted circuit board. Theboardismadeofathininsulating material cladwithathin layer of conductive copper that is shaped in such a way as to thenecessary conductors between thevariousponentsofthecircuit.Theuseofaproperlydesignedprintedcircuitboardisverydesirableasitspeedsconstructionupconsiderablyandreducesthepossibilityofmakingerrors.Toprotecttheboardduringstoragefromoxidationandassureitgetstoyouinperfectconditionthecopperistinnedduringmanufacturingandcoveredwithaspecialvarnishthatprotectsitfromgettingoxidisedandalsomakessolderingeasier.Soldering theponents totheboardistheonlywaytobuildyourcircuit fromthewayyoudoitdepends greatly yoursuccess orfailure. Thisworkisnot4 / 13verydifficultandifyousticktoafewrulesyoushouldhavenoproblems.Thesolderingironthatyouusemustbelightanditspowershouldnotexceedthe25Watts.Thetipshouldbefineandmustbekeptcleanatalltimes.Forthispurposeeveryhandyspeciallymadespongesthatarekeptwetandfromtimetotimeyoucanwipethehottiponthemtoremovealltheresiduesthattendtoaccumulateonit.DONOTfile orsandpaper adirty orwornouttip.Ifthetipcannot becleaned,replace it.Therearemanydifferent typesofsolderinthemarketandyoushouldchooseagoodquality onethatcontainsthe necessaryfluxinits core,toassureaperfectjointeverytime.DONOTusesolderingfluxapartfromthatwhichisalreadyincludedinyoursolder.Toomuchfluxcancausemanyproblemsandisoneofthemaincausesofcircuitmalfunction.Ifneverthelessyouhavetouseextraflux,asitisthecasewhenyouhavetotincopperwires,cleanitverythoroughlyafteryoufinishyourwork.Inordertosolderaponentcorrectlyyoushoulddothefollowing:Cleantheponentleadswithasmallpieceofemerypaper.Bendthematthecorrect distance fromtheponent’sbodyandinsert theponentinitsplaceontheboard.Youmayfindsometimes aponent withheavier gaugeleadsthanusual, aretoothicktoenterintheholesofthep.c.board.Inthiscaseuseaminidrilltoenlargetheholesslightly.Donotmaketheholestoolargeasthisisgoingtomakesolderingdifficultafterwards.Takethehotironandplaceitstipontheponentleadwhileholdingtheendofthesolderwireatthepointwheretheleademerges fromtheboard.Theirontipmusttouchtheleadslightlyabovethep.c.board.Whenthesolderstartstomeltandflowwaittillitcoversevenlytheareaaroundtheholeandthefluxboilsandgetsoutfromunderneaththesolder.Thewholeoperationshouldnottakemorethan5seconds.Removetheiron andallowthesoldertocoolnaturallywithoutblowingonitormovingtheponent.Ifeverythingwasdoneproperlythesurfaceofthejointmusthaveabrightmetallicfinishanditsedgesshouldbesmoothlyendedontheponentleadandtheboard5 / 13track.Ifthesolderlooksdull,cracked,orhastheshapeofablobthenyouhavemadeadryjointandyoushouldremovethesolder(withapump,orasolderwick)andredoit.Takecarenottooverheatthetracksasitisveryeasytoliftthemfromtheboardandbreakthem.Whenyouaresolderingasensitiveponentitisgoodpracticetoholdtheleadfromtheponentsideoftheboardwithapairoflong-noseplierstodivertanyheatthatcouldpossiblydamagetheponent.Makesurethatyoudonotusemoresolderthanitisnecessaryasyouarerunningtheriskofshort-circuitingadjacenttracksontheboard,especiallyiftheyareveryclosetogether.Whenyoufinishyourwork,cutofftheexcessoftheponentleadsandcleantheboardthoroughlywithasuitablesolventtoremoveallfluxresiduesthatmaystillremainonit.0-2VR3=0ohm1%0-20VR3=1.2Kohm1%0-200VR3=12Kohm1%0-2000VR3=120Kohm1%WhenyouhavefinishedallthesolderingontheboardandyouaresurethateverythingisOKyoucaninserttheICinitsplace.TheICisCMOSandisverysensitivetostaticelectricity.Iteswrappedinaluminiumfoiltoprotectitfromstaticdischargesanditshouldbehandledwithgreatcaretoavoiddamagingit.Trytoavoidtouchingitspinswithyourhandsandkeepthecircuitandyourbodyatgroundpotentialwhenyouinsertitinitsplace.Connectthecircuittoasuitablepowersupplyρ5VDCandturnthesupplyon.Thedisplaysshouldlightimmediatelyandshouldformanumber.Shortcircuittheinput(0V)andadjustthetrimmerP1untilthedisplayindicatesexactly «0».IfitdoesnotworkCheck your work for possible dry joints, bridges across adjacent tracks solderingfluxresiduesthatusuallycauseproblems.6 / 13Checkagainalltheexternalconnectionstoandfromthecircuittoseeifthereisamistakethere.Seethattherearenoponentsmissingorinsertedinthewrongplaces.Makesurethatallthepolarised ponents have beensoldered theright round.Makesurethesupplyhasthecorrectvoltage andisconnected therightwayroundtoyourcircuit.-Checkyourprojectforfaultyordamagedponents.SamplePowersupply1 SamplePowerSupply27 / 13译文引言这是一个很容易建立并且非常准确和有用的数字电压表。它被设计成一个面板仪表，可用于直流电源供给器或其他需要有一个准确电压指示的地方。 该电路采用的ADC〔模拟数字转换器〕集成电路CL7107由Intersil 公司生产。该IC用40引脚的情况下整合了所有必要的电路模拟信号转换为数字，可以直接驱动47LED显示。在IC中置的电路是数字转换器，比拟器，一个时钟，一个解码器和一个7LED显示驱动器模拟。在这里它描述了一个可以显示在0-1999电压围的直流电压电路。LED显示屏数字电压表技术规格-特征电源电压：+/-5V 〔对称〕。电源要求：200mA 〔最大〕。测量围：+/-0-1,999V 在四个围。精度：0.1 ％。特征：本钱低。简单的调整。很少的外部元件。数字电压表的根本原那么为了了解电路的运作的原那么，说明 ADC 的集成电路工程是必要的。该成电路具有以下非常重要的特点：8 / 13准确性。无需要一个采样保持电路。它有一个置的时钟。它不需要精度高的外部元件。一个模拟数字转换器(ADC器。这种类型的转换器通常优于其他类型，因为它提供了准确，简洁的设计和它操作将更好的理解。在第一阶段的输入集成电压和最后阶段的输出集成电压中有输出电路会逐渐降低直至到达零参考电压水平。第二个阶段就是所谓的负斜率时期，其持续时间由第一阶段积分器输出而定。作为第一个操作时间是固定的，第二个变量的长度就可以比拟两个这样的输入电压，其实是相对于部参考电压，其结果是编码，然后发送到显示。示意图〔固定16-11-09〕9 / 137段显示器引出线MAN6960这一切听起来很容易，但实际上它是一系列非常复杂的操作，这些都是由ADC集成电路作出了很少的外部元件，帮助它们用来配置工作的电路。详细的电路的工作原理如下。为了进展测量，需要将电压施加于电路的 1和2点，最后通过电路的和C4应用到集成电路的引脚30和31从以下图你可知这是该集成电路的输入(分别为高与低)。R1电阻的C1一起用来设置部振荡器(时钟)，该设置约48Hz。在这个时钟速率大约有三个不同的每秒读数。连接集成电路引脚33和34之间的电容已被选定，以弥补由部参考电压带来的误差，并保持稳定的显示。电容C3和电阻R5在一起的电路是输入电压的集成电路，同时它可防止任何使电路更快的分裂输入电压，从而使错误的可能性大大减少进而使电路更稳定。在没有输入电压时电容器 C5 强迫仪器显示为零。当输入为零时电阻 和P1一起用来调整仪器在设置过程中显示为零。电阻 R6的控制电流允许流经显示以便使电路在没有损坏的前提下显示充分的亮度。至于我们上面已经提到的芯片它能够驱动4个共阳极LED显示屏。这三个最右边的显示器相连，使他们可以显示所有从0到9的数字，而从左边第一个只能显示数字 1，当电压为负“-〞的时候。整个电路工作，从对称ρ5伏直流电电源，这在引脚1(+5V)申请，21(0V)，26(-5V)集成电路。数字电压表印刷电路板的加工首先让我们考虑建立一个印刷电路板上的电子电路的根底知识。 该印刷电板是由薄绝缘铜的导电复合材料薄层形成，这样以形成电路之间的各组成局部的10 / 13并大大减少了决策失误的可能性。为了保护印刷电路板在存储过程中被氧化和保证它到达你所要求的