AE05 BASICvELECTRONICS
TYPICAL QUESTIONS & ANSWERS
v v v
PARTv-vI
OBJECTIVE TYPE QUESTIONS
v v
EachvQuestionvcarriesv2vmarks.
Choosevcorrectvorvthevbestvalternativevinvthevfollowing:
Q.1 Thevbreakdownvmechanismvinvavlightlyvdopedvp-nvjunctionvundervreversevbiasedvconditionvisvcalled
(A) avalanchevbreakdown.
(B) zenervbreakdown.
(C) breakdownvbyvtunnelling.
(D) highvvoltagevbreakdown.
Ans:vA
Q.2 InvavCEv–vconnectedvtransistorvamplifiervwithvvoltagev–
vgainvAv,vthevcapacitancevCbcvisvamplifiedvbyv avfactor
(A) Av (B) 1v+vAv
(C) 1v+vAv (D)v Av2v
Ans:vB
Q.3 Forvavlargevvaluesvofv|VDS|,vavFETv–vbehavesvas
(A) Voltagevcontrolledvresistor.
(B) Currentvcontrolledvcurrentvsource.
(C) Voltagevcontrolledvcurrentvsource.
(D) Currentvcontrolledvresistor.
Ans:vC
Q.4 Removingvbypassvcapacitorvacrossvthevemitter-legvresistorvinvavCEvamplifiervcauses
(A) increasevinvcurrentvgain. (B)vdecreasevinvcurrentvgain.
(C)v increasevinvvoltagevgain. (D)decreasevinvvoltagevgain.
Ans:vD
Q.5 Forvanvop-ampvhavingvdifferentialvgainvAvvandvcommon-modevgainvAcvthevCMRRvisvgivenvby
(A) A v v +vAc (B)v Av
Ac
A Avc
(C) v v +v1vA (D)
c Av
Ans:vB
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,AE05 BASICvELECTRONICS
Q.6 Whenvavstep-inputvisvgivenvtovanvop-ampvintegrator,vthevoutputvwillvbe
(A) avramp.
(B) avsinusoidalvwave.
(C) avrectangularvwave.
(D) avtriangularvwavevwithvdcvbias.
Ans:vA
Q.7 HysteresisvisvdesirablevinvSchmitt-trigger,vbecause
(A) energyvisvtovbevstored/dischargedvinvparasiticvcapacitances.
(B) effectsvofvtemperaturevwouldvbevcompensated.
(C) devicesvinvthevcircuitvshouldvbevallowedvtimevforvsaturationvandvdesaturation.
(D) itvwouldvpreventvnoisevfromvcausingvfalsevtriggering.
Ans:vC
Q.8 Invavfull-wavevrectifiervwithoutvfilter,vthevripplevfactorvis
(A) 0.482 (B)v1.21
(C)v1.79 (D)v2.05
Ans:vA
Q.9 AvmintermvofvthevBoolean-function,vf(x,vy,vx)vis
(A) xv+v yv+vz (B) xvyvz
(C) xvz (D)v(yv+z)vx
Ans:vB
Q.10 Thevminimumvnumbervofvflip-flopsvrequiredvtovconstructvavmod-75vcountervis
(A) 5 (B)v 6
(C)v7 (D)v8
Ans:vC
Q.11 Spacevchargevregionvaroundvavp-nvjunction
(A) doesvnotvcontainvmobilevcarriers
(B) containsvbothvfreevelectronsvandvholes
(C) containsvonevtypevofvmobilevcarriersvdependingvonvthevlevelvofvdopingvofvthevpvorvnvr
egions
(D) containsvelectronsvonlyvasvfreevcarriers
Ans:vA
Q.12 Thevimportantvcharacteristicvofvemitter-followervis
(A) highvinputvimpedancevandvhighvoutputvimpedance
(B) highvinputvimpedancevandvlowvoutputvimpedance
(C) lowvinputvimpedancevandvlowvoutputvimpedance
(D) lowvinputvimpedancevandvhighvoutputvimpedance
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,AE05 BASICvELECTRONICS
Ans:vB
Q.13 InvavJFET,vatvpinch-offvvoltagevappliedvonvthevgate
(A) thevdrainvcurrentvbecomesvalmostvzero
(B) thevdrainvcurrentvbeginsvtovdecrease
(C) thevdrainvcurrentvisvalmostvatvsaturationvvalue.
(D) thevdrain-to-sourcevvoltagevisvclosevtovzerovvolts.
Ans:vC
Q.14 Whenvanvamplifiervisvprovidedvwithvcurrentvseriesvfeedback,vits
(A) inputvimpedancevincreasesvandvoutputvimpedancevdecreases
(B) inputvandvoutputvimpedancesvbothvdecrease
(C) inputvimpedancevdecreasesvandvoutputvimpedancevincreases
(D) inputvandvoutputvimpedancesvbothvincrease
Ans:vD
Q.15 Thev frequencyv ofv oscillationv ofv av tunnel-
collectorv oscillatorv havingv L=v 30µHv andv Cv =v 300pfv isvnearby
(A) 267vkHz (B)v 1677vkHz
(C)v1.68vkHz (D)v 2.67vMHz
1 1
Ans:vB fov = = =v1677v.42vKHz
2 Lc 2 30vvv300v v10v−12
Q.16 Thevopen-loopvgainvofvanvop-ampvavailablevinvthevmarketvmayvbevaround.
(A) 10–1 (B)v 10
(C)v 105 (D)v 102
Ans:vC
Q.17 Thev controlv terminalv (pin5)v ofv 555v timerv ICv isv normallyv connectedv tov groundv throughv av capacitorv(
~v0.01µF).vThisvisvto
(A) protectvthevICvfromvinadvertentvapplicationvofvhighvvoltage
(B) preventvfalsevtriggeringvbyvnoisevcoupledvontovthevpin
(C) convertvthevtriggervinputvtovsharpvpulsevbyvdifferentiation
(D) suppressvanyvnegativevtriggeringvpulse
Ans:vB
Q.18 Thevvaluevofvripplevfactorvofvavhalf-wavevrectifiervwithoutvfiltervisvapproximately
(A) 1.2 (B)v 0.2
(C)v 2.2 (D)v 2.0
Ans:vA
Q.19 ThevthreevvariablevBooleanvexpressionvxyv+vxyzv+v xvyv+vxvyvz
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, AE05 BASICvELECTRONICS
(A) yv+vxz (B) xv+vyz
(C) yv+vxz (D) yv+vxz
Ans:vC
y(xv+vx)v+vxz(vyv+v y)v=v yv+vxz
Q.20 Thevfan-outvofvavMOS-logicvgatevisvhighervthanvthatvofvTTLvgatesvbecausevofvits
(A) lowvinputvimpedance (B)vhighvoutputvimpedance
(C)v lowvoutputvimpedance (D)vhighvinputvimpedance
Ans:vD
Q.21 Invanvintrinsicvsemiconductor,vthevFermi-levelvis
(A) closervtovthevvalencevband
(B) midwayvbetweenvconductionvandvvalencevband
(C) closervtovthevconductionvband
(D) withinvthevvalencevband
Ans:vC
Q.22 Thevreversev–vsaturationvcurrentvofvavsiliconvdiode
(A) doublesvforveveryv10Cvincreasevinvtemperature
(B) doesvnotvchangevwithvtemperature
(C) halvesvforveveryv1Cvdecreasevinvtemperature
(D) increasesvbyv1.5vtimesvforveveryv2Cvincrementvinvtemperature
Ans:vA
Q.23 Thevcommonvcollectorvamplifiervisvalsovknownvas
(A) collectorvfollower (B)v Basevfollower
(C)v Emittervfollower (D)v Sourcevfollower
Ans:vC
Q.24 Invclass–Avamplifier,vthevoutputvcurrentvflowsvfor
(A) avpartvofvthevcyclevorvthevinputvsignal.
(B) thevfullvcyclevofvthevinputvsignal.
(C) halfvthevcyclevofvthevinputvsignal.
(D) 3/4thvofvthevcyclevofvthevinputvsignal.
Ans:vB
Q.25 Invanvamplifiervwithvnegativevfeedback
(A) onlyvthevgainvofvthevamplifiervisvaffected
(B) onlyvthevgainvandvbandwidthvofvthevamplifiervarevaffected
(C) onlyvthevinputvandvoutputvimpedancesvarevaffected
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TYPICAL QUESTIONS & ANSWERS
v v v
PARTv-vI
OBJECTIVE TYPE QUESTIONS
v v
EachvQuestionvcarriesv2vmarks.
Choosevcorrectvorvthevbestvalternativevinvthevfollowing:
Q.1 Thevbreakdownvmechanismvinvavlightlyvdopedvp-nvjunctionvundervreversevbiasedvconditionvisvcalled
(A) avalanchevbreakdown.
(B) zenervbreakdown.
(C) breakdownvbyvtunnelling.
(D) highvvoltagevbreakdown.
Ans:vA
Q.2 InvavCEv–vconnectedvtransistorvamplifiervwithvvoltagev–
vgainvAv,vthevcapacitancevCbcvisvamplifiedvbyv avfactor
(A) Av (B) 1v+vAv
(C) 1v+vAv (D)v Av2v
Ans:vB
Q.3 Forvavlargevvaluesvofv|VDS|,vavFETv–vbehavesvas
(A) Voltagevcontrolledvresistor.
(B) Currentvcontrolledvcurrentvsource.
(C) Voltagevcontrolledvcurrentvsource.
(D) Currentvcontrolledvresistor.
Ans:vC
Q.4 Removingvbypassvcapacitorvacrossvthevemitter-legvresistorvinvavCEvamplifiervcauses
(A) increasevinvcurrentvgain. (B)vdecreasevinvcurrentvgain.
(C)v increasevinvvoltagevgain. (D)decreasevinvvoltagevgain.
Ans:vD
Q.5 Forvanvop-ampvhavingvdifferentialvgainvAvvandvcommon-modevgainvAcvthevCMRRvisvgivenvby
(A) A v v +vAc (B)v Av
Ac
A Avc
(C) v v +v1vA (D)
c Av
Ans:vB
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,AE05 BASICvELECTRONICS
Q.6 Whenvavstep-inputvisvgivenvtovanvop-ampvintegrator,vthevoutputvwillvbe
(A) avramp.
(B) avsinusoidalvwave.
(C) avrectangularvwave.
(D) avtriangularvwavevwithvdcvbias.
Ans:vA
Q.7 HysteresisvisvdesirablevinvSchmitt-trigger,vbecause
(A) energyvisvtovbevstored/dischargedvinvparasiticvcapacitances.
(B) effectsvofvtemperaturevwouldvbevcompensated.
(C) devicesvinvthevcircuitvshouldvbevallowedvtimevforvsaturationvandvdesaturation.
(D) itvwouldvpreventvnoisevfromvcausingvfalsevtriggering.
Ans:vC
Q.8 Invavfull-wavevrectifiervwithoutvfilter,vthevripplevfactorvis
(A) 0.482 (B)v1.21
(C)v1.79 (D)v2.05
Ans:vA
Q.9 AvmintermvofvthevBoolean-function,vf(x,vy,vx)vis
(A) xv+v yv+vz (B) xvyvz
(C) xvz (D)v(yv+z)vx
Ans:vB
Q.10 Thevminimumvnumbervofvflip-flopsvrequiredvtovconstructvavmod-75vcountervis
(A) 5 (B)v 6
(C)v7 (D)v8
Ans:vC
Q.11 Spacevchargevregionvaroundvavp-nvjunction
(A) doesvnotvcontainvmobilevcarriers
(B) containsvbothvfreevelectronsvandvholes
(C) containsvonevtypevofvmobilevcarriersvdependingvonvthevlevelvofvdopingvofvthevpvorvnvr
egions
(D) containsvelectronsvonlyvasvfreevcarriers
Ans:vA
Q.12 Thevimportantvcharacteristicvofvemitter-followervis
(A) highvinputvimpedancevandvhighvoutputvimpedance
(B) highvinputvimpedancevandvlowvoutputvimpedance
(C) lowvinputvimpedancevandvlowvoutputvimpedance
(D) lowvinputvimpedancevandvhighvoutputvimpedance
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,AE05 BASICvELECTRONICS
Ans:vB
Q.13 InvavJFET,vatvpinch-offvvoltagevappliedvonvthevgate
(A) thevdrainvcurrentvbecomesvalmostvzero
(B) thevdrainvcurrentvbeginsvtovdecrease
(C) thevdrainvcurrentvisvalmostvatvsaturationvvalue.
(D) thevdrain-to-sourcevvoltagevisvclosevtovzerovvolts.
Ans:vC
Q.14 Whenvanvamplifiervisvprovidedvwithvcurrentvseriesvfeedback,vits
(A) inputvimpedancevincreasesvandvoutputvimpedancevdecreases
(B) inputvandvoutputvimpedancesvbothvdecrease
(C) inputvimpedancevdecreasesvandvoutputvimpedancevincreases
(D) inputvandvoutputvimpedancesvbothvincrease
Ans:vD
Q.15 Thev frequencyv ofv oscillationv ofv av tunnel-
collectorv oscillatorv havingv L=v 30µHv andv Cv =v 300pfv isvnearby
(A) 267vkHz (B)v 1677vkHz
(C)v1.68vkHz (D)v 2.67vMHz
1 1
Ans:vB fov = = =v1677v.42vKHz
2 Lc 2 30vvv300v v10v−12
Q.16 Thevopen-loopvgainvofvanvop-ampvavailablevinvthevmarketvmayvbevaround.
(A) 10–1 (B)v 10
(C)v 105 (D)v 102
Ans:vC
Q.17 Thev controlv terminalv (pin5)v ofv 555v timerv ICv isv normallyv connectedv tov groundv throughv av capacitorv(
~v0.01µF).vThisvisvto
(A) protectvthevICvfromvinadvertentvapplicationvofvhighvvoltage
(B) preventvfalsevtriggeringvbyvnoisevcoupledvontovthevpin
(C) convertvthevtriggervinputvtovsharpvpulsevbyvdifferentiation
(D) suppressvanyvnegativevtriggeringvpulse
Ans:vB
Q.18 Thevvaluevofvripplevfactorvofvavhalf-wavevrectifiervwithoutvfiltervisvapproximately
(A) 1.2 (B)v 0.2
(C)v 2.2 (D)v 2.0
Ans:vA
Q.19 ThevthreevvariablevBooleanvexpressionvxyv+vxyzv+v xvyv+vxvyvz
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, AE05 BASICvELECTRONICS
(A) yv+vxz (B) xv+vyz
(C) yv+vxz (D) yv+vxz
Ans:vC
y(xv+vx)v+vxz(vyv+v y)v=v yv+vxz
Q.20 Thevfan-outvofvavMOS-logicvgatevisvhighervthanvthatvofvTTLvgatesvbecausevofvits
(A) lowvinputvimpedance (B)vhighvoutputvimpedance
(C)v lowvoutputvimpedance (D)vhighvinputvimpedance
Ans:vD
Q.21 Invanvintrinsicvsemiconductor,vthevFermi-levelvis
(A) closervtovthevvalencevband
(B) midwayvbetweenvconductionvandvvalencevband
(C) closervtovthevconductionvband
(D) withinvthevvalencevband
Ans:vC
Q.22 Thevreversev–vsaturationvcurrentvofvavsiliconvdiode
(A) doublesvforveveryv10Cvincreasevinvtemperature
(B) doesvnotvchangevwithvtemperature
(C) halvesvforveveryv1Cvdecreasevinvtemperature
(D) increasesvbyv1.5vtimesvforveveryv2Cvincrementvinvtemperature
Ans:vA
Q.23 Thevcommonvcollectorvamplifiervisvalsovknownvas
(A) collectorvfollower (B)v Basevfollower
(C)v Emittervfollower (D)v Sourcevfollower
Ans:vC
Q.24 Invclass–Avamplifier,vthevoutputvcurrentvflowsvfor
(A) avpartvofvthevcyclevorvthevinputvsignal.
(B) thevfullvcyclevofvthevinputvsignal.
(C) halfvthevcyclevofvthevinputvsignal.
(D) 3/4thvofvthevcyclevofvthevinputvsignal.
Ans:vB
Q.25 Invanvamplifiervwithvnegativevfeedback
(A) onlyvthevgainvofvthevamplifiervisvaffected
(B) onlyvthevgainvandvbandwidthvofvthevamplifiervarevaffected
(C) onlyvthevinputvandvoutputvimpedancesvarevaffected
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