基于-單片機數(shù)字電壓表電路設(shè)計外文文獻原稿和譯文

外文文獻原稿和譯文外文文獻原稿和譯文原原稿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譯文引言這是一個很容易建立并且非常準確和有用的數(shù)字電壓表。它被設(shè)計成一個面板儀表，可用于直流電源供給器或其他需要有一個準確電壓指示的地方。 該電路采用的ADC〔模擬數(shù)字轉(zhuǎn)換器〕集成電路CL7107由Intersil 公司生產(chǎn)。該IC用40引腳的情況下整合了所有必要的電路模擬信號轉(zhuǎn)換為數(shù)字，可以直接驅(qū)動47LED顯示。在IC中置的電路是數(shù)字轉(zhuǎn)換器，比擬器，一個時鐘，一個解碼器和一個7LED顯示驅(qū)動器模擬。在這里它描述了一個可以顯示在0-1999電壓圍的直流電壓電路。LED顯示屏數(shù)字電壓表技術(shù)規(guī)格-特征電源電壓：+/-5V 〔對稱〕。電源要求：200mA 〔最大〕。測量圍：+/-0-1,999V 在四個圍。精度：0.1 ％。特征：本錢低。簡單的調(diào)整。很少的外部元件。數(shù)字電壓表的根本原那么為了了解電路的運作的原那么，說明 ADC 的集成電路工程是必要的。該成電路具有以下非常重要的特點：8 / 13準確性。無需要一個采樣保持電路。它有一個置的時鐘。它不需要精度高的外部元件。一個模擬數(shù)字轉(zhuǎn)換器(ADC器。這種類型的轉(zhuǎn)換器通常優(yōu)于其他類型，因為它提供了準確，簡潔的設(shè)計和它操作將更好的理解。在第一階段的輸入集成電壓和最后階段的輸出集成電壓中有輸出電路會逐漸降低直至到達零參考電壓水平。第二個階段就是所謂的負斜率時期，其持續(xù)時間由第一階段積分器輸出而定。作為第一個操作時間是固定的，第二個變量的長度就可以比擬兩個這樣的輸入電壓，其實是相對于部參考電壓，其結(jié)果是編碼，然后發(fā)送到顯示。示意圖〔固定16-11-09〕9 / 137段顯示器引出線MAN6960這一切聽起來很容易，但實際上它是一系列非常復雜的操作，這些都是由ADC集成電路作出了很少的外部元件，幫助它們用來配置工作的電路。詳細的電路的工作原理如下。為了進展測量，需要將電壓施加于電路的 1和2點，最后通過電路的和C4應用到集成電路的引腳30和31從以下圖你可知這是該集成電路的輸入(分別為高與低)。R1電阻的C1一起用來設(shè)置部振蕩器(時鐘)，該設(shè)置約48Hz。在這個時鐘速率大約有三個不同的每秒讀數(shù)。連接集成電路引腳33和34之間的電容已被選定，以彌補由部參考電壓帶來的誤差，并保持穩(wěn)定的顯示。電容C3和電阻R5在一起的電路是輸入電壓的集成電路，同時它可防止任何使電路更快的分裂輸入電壓，從而使錯誤的可能性大大減少進而使電路更穩(wěn)定。在沒有輸入電壓時電容器 C5 強迫儀器顯示為零。當輸入為零時電阻 和P1一起用來調(diào)整儀器在設(shè)置過程中顯示為零。電阻 R6的控制電流允許流經(jīng)顯示以便使電路在沒有損壞的前提下顯示充分的亮度。至于我們上面已經(jīng)提到的芯片它能夠驅(qū)動4個共陽極LED顯示屏。這三個最右邊的顯示器相連，使他們可以顯示所有從0到9的數(shù)字，而從左邊第一個只能顯示數(shù)字 1，當電壓為負“-〞的時候。整個電路工作，從對稱ρ5伏直流電電源，這在引腳1(+5V)申請，21(0V)，26(-5V)集成電路。數(shù)字電壓表印刷電路板的加工首先讓我們考慮建立一個印刷電路板上的電子電路的根底知識。 該印刷電板是由薄絕緣銅的導電復合材料薄層形成，這樣以形成電路之間的各組成局部的10 / 13并大大減少了決策失誤的可能性。為了保護印刷電路板在存儲過程中被氧化和保證它到達你所要求的