华南理工大学[电工学]考试真题4.doc

华南理工大学[电工学]考试真题4华南理工大学《电工学》=6V,US2=10V,R1=4Ω,R2=2Ω,R3=4Ω,R4=1Ω,R5=,I2,I3,I4,I5andVAB.(6scores),thetwoidealdiodesareofthesametype,vi=6sinwtV,pleasejudgethestateofD1andD2(onoroff)andplotthewaveformofvoltagevO.(6scores)vi==1V,IS=1A,R1=R2=R3=,I2andvoltageUinsuperposition,whichelementsaresupplyingpower?(8scores)-=R2=2kΩ,R3=.(10scores)=9mA,R1=6kΩ,R2=3kΩ,C=,andthenclosedatt=0,pleasefindtheuC(t)afterSisclosed.(10scores)=8Ω,XL=6Ω,I1rms=I2rms=,Vrms,thepowerfactorandreactivepowerofthetotalcircuit.(10scores)-sequencewyethree-phasesourcehasline-to--=3-,ibB,icC,iNn,theapparentpower,.(10scores)=R2=R3=10kΩ,RF=20kΩ,uI1=1V,uI2=2V,uI3=-1V,.FindthevalueofoutputvoltageuO.(10scores),assumethat:β=50,rπ=1kΩ,determine:(1)plotsmallsignalequivalentcircuit;(2)calculateinputresistorriandoutputresistorro;(3)voltagegainAu.(12scores).312V+uvoo-,determine:(1)plotsmallsignalequivalentcircuit;(putethevoltagegain,inputresistance,andoutputresistance.(10scores)v(,an’slaw,analyzeitslogicfunction.(8scores)=I2=US1=1A2R1+R2US2=2A4+R3R465I3=I4=I5=0AVAB==3V,D1on,D2off,vo=‘‘“US2ISactsalone:I1’=I2’==0.