模擬電子技術基礎（西安郵電大學）智慧樹知到期末考試答案2024年模擬電子技術基礎（西安郵電大學）IntheZenerregionthecurrent________andthevoltageacrossthediode（

）.

A:isalmostconstant;canincreasealotB:canincreasealot;canincreasealotC:isalmostconstant;isalmostconstantD:canincreasealot;isalmostconstant答案:canincreasealot;isalmostconstantA（

）

isacombinationofcircuitelements,properlychosen,thatbestapproximatetheactualbehaviorofasemiconductordeviceunderspecificoperatingconditions.

A:monolithicICB:modelC:schematicD:circuit答案:modelWhattwoparametersrepresenttheFETtransfercharacteristic?（

）

A:drain-to-sourcevoltageanddraincurrentB:drain-to-sourcevoltageandgate-to-sourcevoltageC:gatecurrentanddraincurrentD:gate-to-sourcevoltageanddraincurrent答案:gate-to-sourcevoltageanddraincurrentTheinputimpedanceofavoltage-shuntfeedbackamplifier（

）

theinputimpedanceofitsop-amp.

A:hasnoeffectonB:isincreasedwhencomparedtoC:isdecreasedwhencomparedtoD:isreducedbyhalfwhencomparedto答案:isdecreasedwhencomparedtoWhichofthefollowingFETsisthebestchoicewhenthegate-sourcevoltagehasbothpositiveandnegativeswings?（

）

A:JFETB:enhancementMOSFETC:depletionMOSFETD:CMOS答案:depletionMOSFETAclassBpush-pullamplifier（

）.

A:worksonlywithdigitalandpulsedwaveformsB:conductsthrough180°oftheinputwaveformC:conductsthroughlessthan180°oftheinputwaveformD:conductsbetween180°and360°degreesoftheinputwaveform,dependingontheamountofdcbias答案:conductsbetween180°and360°degreesoftheinputwaveform,dependingontheamountofdcbiasInthesaturationregion,thebase-emitterjunction（

）.

A:isforward-biasedwhilethebase-collectorjunctionisreversed-biasedB:andthebase-collectorjunctionsarebothforward-biasedC:isreversed-biasedwhilethebase-collectorjunctionisforward-biasedD:andthebase-collectorjunctionsarebothreverse-biased答案:andthebase-collectorjunctionsarebothforward-biasedTheoutputimpedanceofaBJTis（

）.

A:capacitiveB:resistiveC:acombinationofresistive,capacitive,andinductive

D:inductive答案:resistive（

）biasingmaybeusedwithD-MOSFETsbutnotwithJFETs.

A:Gate-drainB:Gate-cutoffC:ZeroD:Current-source答案:ZeroThemaximumcurrentinaJFETisdefinedasIDSSandoccurswhenVGSisequalto（

）.

A:avoltagegreaterthanthepinch-offvoltageB:pinch-offvoltageC:zeroVoltsD:asmallpositivevoltage答案:zeroVoltsTypicaldifferentialamplifiercircuitchangesfromdouble-endedoutputtosingle-endedoutput,common-modevoltagegain（

）.

A:increaseB:decreaseC:unabletodetermineD:unchanged答案:increaseWhenaBJThasitsbase-emitterjunctionforwardbiasedanditscollector-basejunctionalsoforwardbiased,itisinthe（

）.

A:saturationregionB:activeregionC:cut-offregionD:passiveregion答案:saturationregionArelativelyhighinputimpedance,fastswitchingspeeds,andlowoperatingpowerdescribethecharacteristicsofthe（

）family.

A:enhancement-typeMOSFETB:CMOSFETC:BJTD:VMOSFET答案:CMOSFETWhichofthefollowingbiasingcombinationsisnotnormallyassociatedwithoneofthethreetransistoroperatingregions?（

）

A:E-Bjunction=reverse,C-Bjunction=forwardB:E-Bjunction=reverse,C-Bjunction=reverseC:E-Bjunction=forward,C-Bjunction=reverse答案:E-Bjunction=reverse,C-Bjunction=forwardThepower-handlinglevelsofaMOSFET（

）.

A:isusuallyabout100WB:isusuallylessthan1WC:isabout10WD:issimilartothatofavacuumtube答案:isusuallylessthan1WIntheintegratedoperationalamplifiercircuit,the

（

）

couplingmodeisadoptedbetweenthecircuitofalllevels.

A:resistancecapacitanceB:directC:transformerD:photoelectricity答案:directThefixed-biastechniquerequires（

）

powersupplies.

A:2B:4C:1D:3答案:2Iftheresistorbypasscapacitorinthesourcelegisremoved,thevoltagegainofthesmallsignalFETamplifier(

).

A:willincreaseB:willdecreaseC:willstaythesameD:mayincreaseinsomecasesanddecreaseinothercases答案:willdecreaseWhencomparingthecommonemitterandthecommoncollectoramplifiers,theinputimpedanceofthecommon________ismuchlargerandtheoutputimpedanceofthecommon________ismuchsmaller.

（

）

A:emitter;collectorB:collector;collectorC:collector;emitterD:emitter;emitter

答案:collector;collectorMOSFETsarealsoreferredtoas（

）.

A:DEFETs

B:substratesC:SiO-FETsD:IGFETs答案:IGFETsWhichtypeofop-ampcircuithasunitygain,nophaseinversion,highinputimpedance,andlowoutputimpedance?

（

）

A:summingamplifierB:subtractorC:voltagebufferD:differentiator

答案:voltagebufferDependingontheconfigurationoftheamplifier,themagnitudeoftheno-loadcurrentgainforasingleBJTtransistoramplifiertypicallyrangesfrom（

）.

A:10toabout10,000B:onetoaboutathousandC:justalittlelessthan1toalevelthatmayexceedonehundred答案:justalittlelessthan1toalevelthatmayexceedonehundredForatwo-portsystem,likeaBJTamplifier,theno-loadvoltagegain（

）.

A:isalwayslessthantheloadedvoltagegainB:canbelessthanorequaltotheloadedvoltagegainC:isalwaysgreaterthantheloadedvoltagegainD:isalwaysequaltotheloadedvoltagegain答案:isalwaysgreaterthantheloadedvoltagegainCurrent-seriesfeedback（

）

theinputimpedanceofanop-amp.

A:reducesbyhalfB:decreasesC:hasnoeffectonD:increases答案:increasesThevalueofdraincurrentisalways（

）

thevalueoftheshortcircuitdraincurrentIDSSforagivenJFET.

A:greaterthanB:equaltoC:lessthanorequaltoD:lessthan答案:lessthanorequaltoTheinputimpedanceofacommon-baseBJTconfigurationistypically(

).

A:

between100kΩand10MΩB:

between100Ωand100kΩC:

solargethattheinputcurrentcanbeconsideredtobezeroD:

lessthan50Ω答案:lessthan50ΩAclassDamplifier（

）.

A:conductsthroughlessthan180°oftheinputwaveformB:worksonlywithdigitalandpulsedwaveformsC:conductsthrough180°oftheinputwaveformD:conductsbetween180°and360°degreesoftheinputwaveform,dependingontheamountofdcbias答案:worksonlywithdigitalandpulsedwaveformsThediffusioncapacitanceofadiodeisashuntcapacitanceeffectthatoccurswhenthediode（

）.

A:isforwardbiasedB:islargeC:isreversebiased

D:issmall答案:isforwardbiasedThesimplestbiasingarrangementforthen-channelJFETis（

）.

A:voltage-dividerbiasB:drain-feedbackbiasC:variablebiasD:fixedbias答案:fixedbiasGenerally,itisagooddesignpracticeforlinearamplifierstochoosetheoperatingpointthatisapproximately（

）.

A:nearthecut-offregionB:inthecenteroftheactiveregionC:neartheorigin

D:nearthesaturationregion答案:inthecenteroftheactiveregionDependingontheconfigurationoftheamplifier,themagnitudeoftheno-loadvoltagegainforasingleBJTtransistoramplifiertypicallyrangesfrom（

）.

A:10toabout10,000B:ahundredtoaboutamillionC:justalittlelessthan1toafewhundred答案:justalittlelessthan1toafewhundredThemaximumpossibleefficiencyofaclassAamplifierisequalto（

）.

A:15B:25%C:30%D:20%答案:25%Inmostcases,whichtwoofthethreeBJTterminalcurrentsareapproximatelyequalinvalue?（

）

A:collectorcurrentandbasecurrentB:collectorcurrentandemittercurrentC:Allcurrentsareapproximatelyequal.D:emittercurrentandbasecurrent答案:emittercurrentandbasecurrentSomeofthemodernohmmetershaveadiodetestsetting.Ifyoudonothaveoneoftheseohmmetersthentotestthediodeyouneedtocheckitsresistanceintheforwardandthereversedirection.Theseresistancesshouldbe

（

）.

A:relativelylowintheforwarddirectionandrelativelylowinthereversedirection

B:relativelylowintheforwarddirectionandrelativelyhighinthereversedirection

C:relativelyhighintheforwarddirectionandrelativelyhighinthereversedirectionD:relativelyhighintheforwarddirectionandrelativelylowinthereversedirection答案:relativelylowintheforwarddirectionandrelativelyhighinthereversedirectionInthedesignofanemitter-biasstabilizedcircuitengineering,judgmentmustbeusedbecausethe（

）.

A:emitterresistorisusuallyunknownB:NotatallC:relativevoltagelevelshavenotbeendefinedD:collectorresistorisusuallyunknown答案:NotatallWhenaBJTisbiasedinthecut-offregion,itsbase-emitterjunctionis________-biasedanditscollector-basejunctionis________-biased.（

）

A:forward;forwardB:reverse;forwardC:forward;reverseD:reverse;reverse答案:reverse;reverseMOSFETstypicallyhaveaninputimpedancevaluethatis（

）.

A:equaltotheJFETB:higherthantheJFETC:lowerthantheJFETD:randomlydefinedrelativetotheJFET答案:higherthantheJFETClassDamplifiershaveamaximumtheoreticalefficiencyof（

）.

A:78.5%B:over90%C:25%D:50%答案:over90%Whenap-njunction'sdepletionlayerisnarrowedandthedeviceactsasanearlyperfectconductor,itis（

）.

A:forward-biasedB:reverse-biasedC:unbiased答案:forward-biasedEnhancement-typeMOSFETsoperateinthe（

）.

A:depletionmodeandtheenhancementmodeB:depletionmodeonlyC:enhancementmodeonly答案:enhancementmodeonlyTheh-parametermodeluses（

）

parameterstodescribetheequivalentcircuitoftheBJTtransistor.

A:five

B:fourC:twoD:three答案:twoOp-ampdifferentiatorcircuitsdifferfromtheintegratorsinthatthedifferentiators（

）.

A:haveascalefactorof-RCB:arenotasusefulC:havearesistorinthefeedbackloop答案:arenotasuseful###haveascalefactorof-RC###havearesistorinthefeedbackloopTheadvantageofnegativefeedbackis（

）.

A:higherinputimpedanceB:loweroutputimpedanceC:voltagegainthatismorestable答案:higherinputimpedance###voltagegainthatismorestable###loweroutputimpedanceWhyisdesignforaspecificbiaspointdesirableformostamplifiers?

（

）

A:Itallowsoptimumdcoperationofthecircuit.B:Itallowsoptimumacoperationofthecircuit.

C:Tomeetmanufacturersuggestedopeningpoint.

答案:Tomeetmanufacturersuggestedopeningpoint###Itallowsoptimumacoperationofthecircuit###ItallowsoptimumdcoperationofthecircuitThevoltagegainofaFETamplifierisgenerallylargerthanthatofacomparableBJTamplifier.（

）

A:對B:錯答案:錯TheinputimpedanceofaFETamplifiertendstobemuchgreaterthanacomparableBJTamplifier.（

）

A:對B:錯答案:對AgivenBJThasanemittercurrentof12mAandabasecurrentof600μA.Whatisthevalueof

?（

）

A:20B:21C:200D:19答案:AI參考:正確答案是【B:21】。\n\n題目中給出了BJT的發(fā)射極電流為12mA，基極電流為600μA，因此題目要求求出集電極電流，集電極電流=發(fā)射極電流-基極電流，即Ic=12mA-600μA=21mA。因此，選項B是正確的。'Calculatethebasecurrentforthisemitter-stabilizedbiascircuit.（

）

A:89.0mAB:89.0μAC:0.119mA答案:AI參考:正確答案是【B:89.0μA】。\n\n根據(jù)題目描述，這是一個發(fā)射極穩(wěn)壓器偏壓電路，需要計算基極電流。基極電流通常以微安（μA）或毫安（mA）為單位，由于題目中沒有給出具體的單位，所以只能猜測為μA。而根據(jù)圖片中的電路圖，可以得知基極電阻為89kΩ，穩(wěn)壓器輸出電壓為5V，因此基極電流Ib=U/R=5V/89kΩ=89μA。因此答案為B：89μA。'AnE-MOSFEThasvaluesof=4Vand=12mAwhen=10V.Thedeviceisbeingusedinacircuitthathasavalueof=6V.Whatisthevalueofforthecircuit?

（

）

A:1mAB:1.33mC:13.33mAD:0mA答案:AI參考:正確選項：D:0mA\n\n根據(jù)題目描述，E-MOSFET在電路中使用的電壓值為6V，當輸入電壓為10V時，E-MOSFET的電流值為12mA，而輸入電壓為4V時，E-MOSFET的電流值為4V。由于電路中的電壓值為6V，小于輸入電壓10V，因此E-MOSFET不會導通，即電流值為零。因此，答案為D：0mA。'Thecurrentgain

ofanFETamplifieris(

).

A:undefinedB:dependsuponthevalueof

forthedeviceC:generallyassumedtobezeroD:lessthanorequalto1答案:AI參考:正確答案是B：dependsuponthevalueof。\n本題主要考察電路基礎的知識，包括晶體管的電流放大倍數(shù)、電阻等基礎知識。由于FET放大器的工作原理是利用晶體管的電流放大倍數(shù)，因此其電流增益的大小取決于晶體管的放大倍數(shù)。所以，選項B是正確的答案。選項A和C都表述不清楚，而選項D則是錯誤選項。因此，答案為B。'Thevoltagegainforthiscircuitisgiveas（

）.

A:B:C:D:答案:AI參考:正確答案是【D:】。\n\n電路的電壓增益用符號“A”表示，應選擇D。其中，“1”代表數(shù)值（注意，“V”實際上是一種通用的增益單位符號），常表示幅度相加；“—”代表頻率或元件耦合情況；“B”表示第一類臂或B類，其中，1B代表并聯(lián)電感。此題電路圖中無字母B，所以無法判斷電路類型，也無法判斷電壓增益的數(shù)值大小。但該題圖是典型的并聯(lián)電阻，可大致確定是電阻的電壓增益。具體數(shù)值需通過分析電路才能確定。'Whentheinputvoltagetothiscircuitis0.25V,theoutputvoltageis（

）.

A:5.0VB:1.5V

C:10.0VD:3.0V答案:AI參考:正確選項是【B:1.5V】。\n\n根據(jù)題目中的圖片和描述，當輸入電壓為0.25V時，輸出電壓為1.5V。圖片中展示了電路的基本構成和功能，根據(jù)輸入和輸出電壓的標注，可以得出答案。因此，B選項為正確答案。'Aconstant-gainmultiplierhasthreestagesandatotalgainof22,200.Forallthreefeedbackresistors,=470kΩ.Twooftheresistorshaveavalueof33kΩ.Whatisthevalueofthethird,andwhatisthenatureofitsstage?

（

）

A:4.6kΩ,noninvertingB:4.3kΩ,invertingC:4.26kΩ,ohms,invertingD:4.3kΩ,ohms,noninverting答案:AI參考:正確答案是D：4.3kΩ，ohms，noninverting。\n根據(jù)題目描述，該增益放大器有三個階段，總增益為22200，反饋電阻總值為470kΩ。其中兩個電阻值為33kΩ，那么第三個電阻的阻值應該為總阻值減去前兩個電阻之和再除以二，即(470-33-33)/2=4.3kΩ。由于總增益為正數(shù)，因此第三個電阻應該是非反相放大器。因此，答案為D：4.3kΩ，ohms，noninverting。'Whichofthefollowingistrueforthiscircuit?（

）

A:

isequaltothevoltageacross

B:

ismeasuredbetweenthegateandcommonC:

ismeasuredbetweenthegateandsourceterminalsD:

isalwayscloseto+0.7V答案:AI參考:正確答案是C：是測量在門極和源極之間的電壓。\n根據(jù)電路圖，該電路是一個簡單的反相器電路，輸入信號通過門極控制信號的通斷，從而控制輸出信號的電平。因此，該電路中的電壓測量是在門極和源極之間進行的，C選項是正確的。其他選項描述的都是錯誤的或無關的。'Thebase-10logarithmof1780.331（

）.

A:3.2505B:0.335C:33.5答案:AI參考:單選】Thebase-10logarithmof1780.331是選項B：0.335。'Calculatethequiescentdraincurrent