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ECA1) Critical capacitance with smallest equivalent resistance that determines the lower cut off ofCB amplifier is

a) I/P coupling capacitorb) Emitter bypass capacitor if c1 = c2c) c2 output coupling capacitord) None.

2) Non-linear distortion is maximum in a) classB mode

b) class A modec) class AB moded) class C mode

3) typical value of rbb of Ge BJT at room temperature of Ie =1.3ma 100 ohms

4) cascade amplifier is 2- transistor combination hasa) collector of first transistor is connected to the base of second transistorb) collector current of first transistor is same as emitter current of second transistorc) emitter current of first transistor is same as the collector current of the second transistord) none

5) resultant phase shift of odd no of CE amplifier stages at mid band frequency is a)3600

b) 1800

c) 450

d) 900

6) major drawbacks of Darlington transistor pair isa) low current gain compared to single emitter followerb) dependence of AV on transistor selected conditionc) low i /p impedance compared to single emitter followerd) dependence of h-parameters on quiescent point.

7) lower cutoff &higher cutoff frequency of rc coupled amplifier area) both zero

b) both infinityc) zero & infinity respectivelyd) similar to those of CE stage

8) the miller input capacitance in CB AMP IS

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a) large compared to miller capacitance in CEb) very large because of +ve voltage gain in CBc) small because of +ve voltage gain in CBd) is not negligible compare to other capacitance

9) identify the correct relationshipa) f alpha ~ f betab) f beta >> f alphac) f alpha ~ ftd) f alpha >> f beta

10) final stage of multistage amplifier is generally a) apre-amplifier

b) a voltage post amplifierc) a power amplifierd) a microphone amplifier

11) Max conversion efficiency of a series fed class A power amplifier isa) 75

b) 100c) 50d) 25

12) even harmonics are not present in the o/p ofa) class A transformer coupled amplifier

b) class c amplifierc)class A amplifierd) class B push pull amplifier

13) voltage gain of an amplifier reduces to 1/(root 2)its maxa) break frequencyb) miller frequencyc) half power frequencyd) cutoff frequency

14) Identify the correct statement regarding the voltage gain of a CE transistor amplifiera) it increases with increase in ac load R

b) it is independent of ac load R & is largec) it decreases with increase in ac load Rd) it is always approximately unity

15) Phase reversal between i/p & o/p signal voltages occurs ina) common base amplifier

b) common drain amplifier



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c) common gate amplifierd) common source amplifier

16) Identify the incorrect statement[ d ]

a) frequency distortion in an amplifier is mainly due to the reactive component circuitb) amplitude distortion is also referred to as non-linear distortionc) distortion in amplifier due to unequal phase shifts at different frequencies is called delay

distortiond) phase shift distortion is same as frequency distortionans: [D ]

17) Resultant current gain of a Darlington pair individual current gain of hfe is[ d ]

a) hfe/2b) hfec) 2hfed) hfe2

ans: [ D ]

18) o/p voltage of a non ideal differential amplifier is[ c ]

a) zerob) Ad Vdc) (AdVd+ AcVc)d) AcVcans: [ C ]

19) rce >> rbe condition is applicable in hybrid -pie equivalent of CE amplifier becausea) collector base junction is reverse biased & emitter base junction is forward biased

b) o/p R is always much larger than i/p Rc) b is the internal base terminald) base region is extremely tin compared to emitter & collector terminals

20) expression for short circuit current gain bandwidth[ d ]

a) gm/2pie hfe (ce+cc)b) gm/(ce+cc)c) gm/ hfe (ce+cc)d)gm/2pie (ce+cc)



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ans:[ D ]

21) the parameter with 0c/watt as its units of measurement is[ a ]

a) thermal expansionb) thermal coefficientc) thermal resistanced) thermal powerans : [ A ]

22) Even harmonics in the o/p are connected in push - pull configurations only if[ a ]

a) both transistors are perfectly matchedb) both NPN & PNP transistors are usedc) A phase inversion is not used at inputs of 2 transistorsd) two power supplies are usedans:[ A ]

23) i/p &o/p capacitors in a transistors amplifier are not referred to as[ a ]

a) inter electrode capacitorsb) coupling capacitorsc) blocking capacitorsd) dc de-coupling capacitorsans : [ A ]

24) FET amplifier configuration , which is similar to CC BJT is[ b ]

a) common gate amplifierb) common drain amplifierc) common source amplifierd) swamped source resistor amplifier

ans:[ B ]

25) identify the expression for voltage gain CE & fet amplifier at low frequency[ c ]

a) -gm rd Rl /(rd + Rl)b) gm rd Rl / ( rd +Rl+ gm rd Rl)c) gm rd Rl /(rd + Rl)



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d) Rl || rd / (1+ gm rd)ans: [ C ]

26) Resultant phase shift of even no of CB amplifier stage at frequency below lower cutofffrequency [ d ]

a) always a multiple of 2 pieb) product of phase shift introduced by individual stagesc) always 1800

d) sum of the phase shifts introduced by individual stagesans: [ D ]

27) 2-stage rc coupled amplifier is configured as[ a ]

a) 2 capacitively coupled CE stages cascadedb) a CE stage capacitively coupled to a CC stagec) 2 capacitively coupled CB stages cascaded.d) 2 capacitively coupled CC stages cascadedans: [ A ]

28) Identify the incorrect statement for a high frequency hybrid pie model of a BJT is[ a ]

a) high frequency hybrid pie capacitances can be expressed in terms of low frequency h-parameters

b) capacitance between collector & base terminal of a BJT is called overlap -diode capacitancec) ' B' represent internal base terminald) high frequency hybrid pie conductances can be expressed in terms of low frequency h-

parameters.ans:[ A ]

29) identify false statement[ c ]

a) fbeta & Ic exhibits a peak value of a particular ic.b) unity gain band width Ft is the function of Icc)ft & Ic both are functions of f beta

d) Ft variation with Ic is similar to hfe variation with Tans: [ C ]

30) during the mid band frequency the gain of amplifier is[ d ]



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a) 1/(root 2) times Max valueb) minc)unityd) constantans: [ D ]

31) CB amplifier of BJT is similar in behaviour with following FET configuration[ a ]

a)common gate amplifierb) common drain amplifierC) common source amplifierd)swamped source resistor amplifierans:[ A ]

32) 2-transistor cascade with both collectors tied together & emitter of the transistor connectedto the base of the transistor is

referred to as[ a]

a) Darlington pairb) CE &CC cascadec) cascade amplifierd) differential pairans: [ A ]

33) o/p voltage of an ideal differential amplifier[ b ]

a) zerob) Ad Vdc)Ad Vd + AcVcd) AcVcans:[ B ]

34) bandwidth of an amplifier with lower & higher cutoff frequency Fl & Fh .& quantity factor Qis [ a ]

a) Fh - F lb) Fh/ qc) (Fh-Fl)/1.414d) q-Flans: [ A ]

35) identify the expression for voltage gain CD & fet amplifier at low frequency



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[ b ]

a) -gm rd Rl /(rd + Rl)b) gm rd Rl / ( rd +Rl+ gm rd Rl)c) gm rd Rl /(rd + Rl)d) Rl || rd / (1+ gm rd)ans: [ B ]

36) the i/p impedance of cascade amplifier is[ b ]

a) hicb) hiec) infinityd) hibans: [ B ]

37) the transconductance gm of a transistor depend on[ b ]

a) temperatureb) operation frequencyc) CE voltaged) C cans : [ B ]

38) ft for a ce amplifier is defined as[ b ]

a) the frequency at which the CE current gain falls to half its Max valueb) frequency at which CE current gain becomes unityc) frequency at which CE voltage gain falls to half its Max valued) frequency at which CE voltage gain becomes unityans: [ B ]

39) the capacitance determining the corner frequency lag network at the i/p of CE amplifier is[ b ]

a) miller i/p capacitorb) c wiringc) external capacitor at the based)cbeans: [ B ]



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40) i/p signals swing in class A power amplifier is restricted to[ d ]

a) a small portion around Q point in active regionb) entire portion around Q point in saturationc) entire portion around Q point in cutoffd) entire portion around Q point in activeans: [ D ]

41) transistor in class C amplifier is based beyond cutoff region to[ b ]

a) ensure reduced distortion of o/p signalb) ensure conduction angle of less than 1800

c) ensure conduction angle of transistor for entire i/p cycled) ensure o/p wave shape to the replica of i/p wave shapeans: [ B ]

42) if Av is the voltage gain of an amplifier in db & Ai is its current gain in db then power gain ofamplifier in db is [ d ]

a) Av- Aib) Av/ Aic)10log 10 Av/ Aid) Av+Aians : [ D ]

43) at frequency below lower cut off frequency in CE amplifier coupling capacitor at the base ofthe amplifier form an LPF [ b ]

a) with emitter resistanceb) with i/p resistancec) with o/p resistanced) with base resistanceans: [ B ]

44) advantage of impedance type inter stage coupling is[ c ]

a) very wide band & frequency independent gain curveb) flat response of frequency in mid band regionc) no dc voltage drop across collector load



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d) no requirement of bulky components all frequencyans: [ C ]

45) resultant phase shift of odd number of CE amplifier stages at mid band frequency is[ b ]

a) 3600

b)1800

c) 450

d) 900

ans: [ B ]

46) major draw back of Darlington transistor pair[ d ]

a) low current gain compared to single emitter followerb) dependence of Av on transistor selectedc) low i/p impedance compared to single emitter followerd) dependence of H -parameters on quiescent conditionsans: [ D ]

47) lower cutoff & higher cut off frequency of an rc coupled amplifier are[ c ]

a) both zerob) both infinityc) similar to of CE staged) zero& infinityans: [ C ]

48) main characteristic features of differential amplifier is absence of frequency dependentcomponents

49) identify the incorrect statement for a Hybrid pie model of a BJT[ b ]

a) base width modulation due to earlier effect results in variations in collector emittervoltages

b)Hybrid pie model cannot be used for analysis of transistors at high frequenciesc) High frequency hybrid pie conductance can be expressed in terms of low frequency H

parametersd) All the conductances & capacitances of Hybrid pie model are independent of operating



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frequenciesAns: [ b ]

50) Frequency of Fbeta = a product of current gain & band width of CE amplifier

51) The miller i/p capacitance in CB amplifier[ c ]

a) Is large compared to miller capacitance in CEb) is very large because of +ve voltage gain in CBc) is small because of +ve voltage gain in CBd) not negligible compared to other capacitanceans: [ C ]

52) in class A amplifier flow of electric current in terms of i/p signal cycle is for 3600

53) an ideal voltage will have effective o/p impedance =[ b ]

a) no particular valueb)zeroc) always a complex valued) infinityans: [ B ]

54) type of inter stage coupling resulting in highest overall gain[ c ]

a) direct couplingb)inductive couplingc) RC couplingd) transistor coupling

ans : [ C ]

55) main disadvantage of Darlington pair amplifier is[ d ]

a) low i/p impedanceb) low current gainc) high o/p impedanced)high leakage currentans: [ D ]

56) ideal value of CMRR of differential amplifier is[ d ]



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a) unityb) zeroc)100d) infinity

ans: [ D ]

57) CE is the capacitance of forward biased junction & is therefore[ c ]

a) independent of collector currentb) much lager than Ccc) mainly diffusion capacitanced) mainly transition capacitanceans: [ C ]

58) dissipation capability of a transistor is defined as[ a ]

a) capability to launch heat generated into the surroundingsb) deviation in power delivered to load resistorc) capability to withstand the variation in dc power at operating powerd) deviation in o/p & i/p signal wave shapesans: [ A ]

59) increased conversion efficiency in class B over class A operation is mainly due to[ b ]

a) elimination of all higher harmonicsb) elimination of dc current in the loadc) usage of single power supplyd) elimination of cross over distortionans: [ B ]

60) higher cutoff frequency of transistor amplifier is mainly because of[ a ]

a) inter electrode capacitanceb) bypass capacitancec) blocking capacitanced ) coupling capacitanceans: [ A ]



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61) phase difference between o/p voltage &i/p voltage of a CC amplifier at mid band frequencies[ b ]

a) 1800

b) 00

c) 450

d) 900

ans : [ B ]

62) phase difference between o/p voltage &i/p voltage of a CG amplifier at mid band frequencies[ b ]

a) 1800

b) 00

c) 450

d) 900

ans : [ B ]

63) audio power amplifiers are also generally referred to as large signal amplifiers

64) ratio of slopes of the gain curve of an amplifier below lower cutoff frequency & above cutofffrequency is [ b ]

a) 3b) unityc)2d) 6ans: [ B ]

65) the capacitors that are short circuited at low frequencies in CE amplifier are[ d ]

a) o/p coupling capacitorsb) i/p coupling capacitorsc) emitter bypass capacitorsd) inter electrode capacitorans:[ B ]

66) the critical capacitance that determines the overall cut off frequency of an amplifier is theone which sees an equivalent resistance [ a ]

a) of minimum valueb) of Max valuec) of infinity value



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d) equals to its reactance value at that frequencyans: [ A ]

67) distortion in amplifiers due to unequal amplitude gains at different frequencies is referred toas [ c ]

a) phase shift distortionb) amplitude distortionc) frequency distortiond) delay distortionans : [ C ]

68) slope of the gain curve of an amplifier below cut off frequency is[ a ]

a) -20 db decadeb) 6 db decadec)-6 db decaded) 20 db decadeans : [ A ]

69) the CE short circuit current gain in db at frequency f = Ft is[ d ]

a) hfe/1.414b) unity

c) hfed)zero

ans: [ D ]

70. The frequency at which CE is short circuit current gain becomes unity is representedby__fT_______

71. Non linear distortion is maximum ina) Class B mode a) Class A modea) Class AB mode d) a) Class C modeAns: (b)

72. Even harmonics are not present in the o/p of Class B push pull amplifier.

73. Phase difference between o/p and i/p voltages of a transistor amplifier at lower cut offfrequencies isa)180 b) 45 c) 0 d) 90Ans: (b)



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74. All frequencies below lower cut off frequency in a CE amplifier, the coupling capacitor at thebase of the amplifier forms a LPFa)with RE b)Rip c)RB d)RopAns: (b)

75. A CC amplifier is characterized by approximatelyA)unity power gain b)unity i/p ,o/p impedance ratioc)unity voltage gain d) unity current gainAns: (c)

76. Voltage gainof a given CS FET depends on itsa)Dynamic drain resistance b)i/p impedancec) Amplification factor d)Drain load resistanceAns: (d)

77. Identify the expression for o/p resistance of a CE amplifier at lower frequencies isAns: 1/[ho-hrhf/hi+rs]

78. The type of inter stage coupling used at extremely low frequencies isa)Inductive coupling b)RC couplingc) Transformer coupling d) Direct couplingAns: (d)

79. Resultant phase shift of even no of CG amplifier stages at higher cut off frequencies isAns: Sum of phase shift introduced by individual stages.

80. According to Millers theorem, inter electrode capacitances Ccb for a CE amplifier of gain Aresults in an miller i/p capacitance of

a) Ccb (A-1)/A b) Ccb A/ (A-1)c) Ccb (1-A) d) Ccb / (A-1)

Ans: (a)

81. A two transistor combination in CE, CC is not characterized bya)AI<1 a)AV>1 c) a)AV<1 d) Small RoAns: (c)

82. Identify which of the following are not used for high frequency transistor modela) Hybrid Π model b) Giacolette modelc) Transconductance model d) Eba-Molls modelAns: (b)

83. Expression for cut off frequency in hybrid parameters



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a) gm / Cc+Ce b) gm / Cc+Ce (2 Π hfe)c) gm / Cc+Ce (hfe) d) gm / (Cc+Ce) 2 ΠAns: (b)

84. The corner frequency fhin due to Rin and cin and fhout due to Cout and RL of a CC amplifier aresuch thata) fhin>> fhout b) fhin<< fhout c) fhin< fhout d) fhin= fhoutAns: (d)

85. The transformer ratio (N1:N2) necessary to match a 16Ω speaker to an amplifier to obtain aneffective load resistance ofa)25:1 b) 200:1 c)10K:16 d)10:16

86. Identify incorrect statement for amplifierAns: transistor conduction is for 180

87. The relationship between maximum collector power to maximum O/P power dissipation isAns. Pc max = 0.4 Po max

88) Slope of gain curve of an amplifier beyond11 thehigher cut frequency is

(a) 6db/decade (b) -20db/decade(c) 20db/decade (d) -6db/decadeAns: (b)

89) Distortion in amplifiers due to the non-lineardynamic curve of the active device is referred to as

(a) amplitude distortion (b) frequency distortion(c) phase shift distortion (d) delay distortionAns: (D)

90) Differential voltage gain Ad of a difference amplifier with a voltage gain of individualamplifier circuit A1 and A2

(a) A1-A2 (b) (A1+A2)/2(c) (A1-A2)/2 (d) A1+A2Ans: (c)

91) Cc is the capacitance of the reverse biased collector base junction and is therefore(a) Independent of collector current(b) mainly transistor capacitance(c) much larger than Ce



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(d) mainly diffusion capacitanceAns: (b)

92) Cross over distortion in class B amplifier is due to(a) finite cut-off voltage of the two transistors(b) non-identical behaviour of the two transistors(c) elimination of two power supplies in the circuit(d) elimination of even harmonics in the o/pimpedanceAns: (a)93) Large i/p impedance and small o/p impedance are possible inAns) common collector amplifier

94) Identify the correct statement with reference to class B amplifierAns) Even harmonics are cancelled in the ……

95) CE amplifier is characterized byAns) moderate i/p impedance

96) Phase relationship between o/p and i/p voltage of a CS amplifier for frequency below lowercut-off frequency is

(a) both are in phase(b) o/p lags i/p(c) output leads i/p(d) both are 180 out of phaseAns: (c)

97) Identify correct statementsAns) Gain and Bandwidth change such that product is same

98) Cascading of two identical amplifiers with individual gains of 100results inAns) overall gain of 8db

99) Resultant phase shift of 6 common source amplifier stages cascaded at mid band frequency isAns) 180

100) Major advantage of boot strap Darlington pair over single Darlington pair is(a) High overall Av with proper DC biasing(b) increased Ai irrespective of bias condition(c) high i/p impedance irrespective of bias condition(d) increased Ai depending upon the bias conditionAns: (c)

101) The frequency up to which hybrid п model is valid is

(a) 3ft (b) 2ft (c) ft/3 (d) ft/2Ans: (c)



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102) Identify correct statement in the following statements(a) for wide brand operation RL ≤2kΩ(b) the band width of CE amplifier is dependent on the load resistance RL(c) At high frequency o/p conductance are generally negligible compared to RL(d) For wide band operation RL >>2kΩAns: (a)

103) The location of operation point of a class A amplifier isAns) active region

104) Total harmonic distortion is maximum inAns) class C

105) Effect of small value of unbiased emitter resistance in CE amplifier is

(a) Increase in voltage gain at mid band frequency(b) Decrease in Av at high frequency(c) Nothing on voltage gain at mid band frequency(d) Decrease in Av at mid band frequencyAns: (d)

106) The mid band gain of BJT is 200 and its bandwidth is 1MHz .If circuit parameters arechanged such that the gain reduces to 10,the bandwidth coil

(a) remains same (c) also reduces to 1/10th

(c) increases to 20MHz (d) increases to 10 MHzAns: (c)

107) Resultant phase shift of five CE emitter amplifier stages cascaded at mid band frequenciesis

(a) 360 (b) 180 (c) 45 (d)90Ans: (b)

108) Typical value of gm of Ge BJT at room temperature and Ic=1.3mA is

(a) 50mA/volt (b) 1000Ω (c) 80kΩ (d) 4MΩAns: (a)

109) [hie – gm/hfe] represent hybrid п conductance

(a) Feed back conductance gb′c



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(b) Base spreading conductance gbb′(c) o/p conductance gce(d) i/p conductance gb′c

Ans: (b)

110) Frequency response of an amplifier is defined as

(a) variation of amplifier frequency as a functionof its voltage gain

(b) variation of magnitude of voltage gain as afunction of phase of the voltage gain

(c) variation of magnitude and phase of voltagegain with variation in signal frequencies

(d)variation of amplifier frequency as a function of the phase of its voltage gainAns: (c)

111) Critical capacitance along the smallest equivalent resistance that determines the lowercut-off frequency of a common drain amplitude is

(a) C1,input coupling capacitor(b) Cs,source by pass capacitor(c) Cs,source by pass capacitor ,only if C1=C2(d) C2,output coupling capacitorAns: (d)

112) Resultant upper-cut-off frequency of two identical stages cascaded with individual uppercut-off frequency of 10 KHz is

(a) 6.4 KHz (b) 15.625KHz (c) 10 KHz (d) 5 KHzAns: (a)

113) In a two stage BJT cascade amplifier

(a) I/P resistance is comparable with hie of a singleCE stage

(b) O/P resistance is as low as hoe of a single CEStage

(c) Reverse voltage gain is much larger than hre of aSingle CE stage

(d) Forward current gain is much smaller than hfe ofSingle CE stageAns: (c)



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114) Typical value of rb′c of Ge BJT at room temper--ture and Ic=1.3mA is(a) 1000Ω (b) 4MΩ (c) 100Ω (d) 80KΩAns: ( b)115) Identify the conductance that is not included in hybrid п- model(a) Base emitter conductance, gbe(b) O/P conductance, gce(c) Feed back conductance,gb′c(d) I/P conductance, gb′cAns: (a)

116) Class C amplifier find applications in thefollowing

(a) amp modulation circuits(b) driving loud speakers(c) switching devices(d) comparatorsAns: (a)

117) Mid frequency amplifier range of an amplifier is defined as those frequencies more than 10times that of lower frequencies and less than 0.1 times that of higher frequency in amplifier doesnot have any mid frequency range if

(a) fH<100fL (b) f<0.01f (c) fH >100fL (d) f>100fLAns: (a)

118) The mid band voltage gain of an amplifier with band width of 1MHz is 10db,if the circuitcomponents are changed such that the gain becomes 7db ,its bandwidth becomes

(a) 700 KHz (b) 2 MHz (c) 500 KHz (d) 1 MHzAns: (b)

119) Resultant voltage gain and phase shift in an n-stage cascaded amplifier with individualgains, A1, A2, A3 …An and phase shifts ө1, ө2 …өn is(a) Ar=A1.A2.A3……..An and ө=ө1+ө2+……. +өn(b) Ar=A1.A2…………An and ө=ө1.ө2…………өn(c) Ar=A1+A2+………+An and ө=ө1.ө2………..өn(d) Ar=A1+A2+……….+An and ө=ө1+ө2+…….+өnAns: (a)120) Break frequency is the frequency at which the capacitive reactance (Xc) and equivalentresistance (Req) at a point of connection in a circuit have following relation

(a) Xc<<Req (b) Xc=Req=∞ (c) Xc=Req (d) Xc>>ReqAns: (c)



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121) Basic advantage of DC of amplifier stage is

(a) Ability to provide impedance matching(b) Ability to provide very small mid band region(c) Ability to provide narrow and resonant type of frequency response(d) Ability to amplify DC and very low frequency signalAns: (d)

122) Two stage common emitter amplifier configuration with emitters tied together, i/p’s at basesand o/p’s at collectors is called as

(a) Differential pair (b) Cascode amplifier(c) Boot strap Darlington pair (d) Darlington pairAns: (a)

123) Effect of resistor N/W for biasing theDarlington resistorAns) Reduction in overall I/P impedance

124) If a power transistor conducts only during +ve half cycle of i/p signal , the class of operationof the amplifiers isAns) Class B

125) Max conversion efficiency of a Class B power amplifier isAns) 78.5%

126) If the signal voltages and currents at the i/p of a transistor amplifier are within 1/10th of DCoperating point values then transistor is said to be in

(a) small signal mode(b) low frequency mode(c) frequency independent mode(d) DC operating mode

Ans: (a)

127) Phase reversal between O/P and I/P voltages in a CE amplifier occurs at

(a) mid band frequency (b) high cut off frequency(c) all the frequency (d) lower cut off frequencyAns: (a)

128) Resonant peak in the frequency response occurs in(a) DC coupling (b) RC coupling(c) direct coupling (d) Transformer coupling



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Ans: (d)

129. If 2 signals of some amplitude and frequency are applied to a differential amplifier theoutput is mainly due to the phase difference between the input signals

130. The output conductance gb’e in terms of low frequency h parameter is given by αD / hfe Re .

131. If power transistor conducts for the entire cycle of input signal , the mode of power amplifieris Class A.

132. Identify the incorrect statement with reference to Class B amplifierAns: A phase inversion is not required at input in Push Pull Amplifier.

133. Doubling the voltage gain of an amplifier results in increase of voltage gain in dB by 3.01.

134. To obtain a constant and high value of voltage gain at midband frequency in CE AmplifierCE should be large enough such that Xce<<RE at midband frequencies.

135. A differential amplifier cannot be considered as ground input ,single ended output.

136. Cross over distortion in Class B amplifier is due to finite cut-in voltage of 2 transistors.

137. If there are 2 uncoupled high pass filter sections in the equivalent circuit of an amplifierwith fL1 and fL2 as cutoff frequency , then the overall lower cutoff frequency of the amplifierapproximately isa) fL2 - fL1b) smaller of fL2 and fL1c) fL2 + fL1d) Larger of fL2 and fL1 , if fL2 and fL1 differ by more than a decade.Ans: (d)

138. The phase relationship between output and input voltages of a CS amplifier for frequencyabove higher cut off frequency isa) both are 180 degrees out of phaseb) output leads inputc) both are in phased) output lags inputAns: (d)



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139. According to Millers theorem , the inter-electrode capacitance, Ccb for a CE amplifier of gainA results in a Miller output capacitance ofa) Ccb(A-1)/A b) Ccb A/(A-1) c) Ccb(1-A) d) Ccb /(A-1)Ans: (a)

140. If V1 = -V2 = 0.5 V are the two input signals applied to a differential amplifier , identify theincorrect statementa) Common mode voltage is 0b) Differential mode voltage is 1Vc) Differential mode voltage is 0d) Output voltage = Differential mode gainAns: (c)

141. Gain in dB as a negative number indicatesa) an absolute gain less than 20b) an absolute gain less than 1c) an absolute gain less than 0d) Phase reversal between i/p and o/pAns:

142. Crossover distortion in Class B amplifiers can be eliminated by modifying the configurationto Class AB .

143. A voltage gain equal to 0dB of an amplifier corresponds toa) Power gain of 2b) Voltage gain of 2c) Voltage gain of unityd) Power gain of zero

144. Configuration of transistor amplifier that acts as a buffer for impedance matching is

145. Resultant lower and upper cut off frequency f1n and f2n of an n stage cascaded identicalamplifier is

146. A cascade amplifier is a combination of147. Typical value of Cc of high frequency hybrid ∏ model of a BJT is

148. Resultant upper 3dB frequency of ‘n’ identical upper cut off frequency given asa) ( f2 )n

b) f2 √(21/n-1)c) f2 /√(21/n-1)d) f2Ans:



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149. Base width modulation due to early effect results in variations in collector emitter voltages

150. Input impedance is high and output impedance is low in the following transistorconfigurationsa) CC b) CB c) CC and CB d) CEAns:

151. Identify the correct statementa) Change in bandwidth for any change in its gain is always 3dBb) If the gain of an amplifier decreases by 3 dB , its bandwidth remains the same.c) Gain and bandwidth of an amplifier change such that their product always remains the same.d) If the gain of an amplifier increases by 3 dB its bandwidth also increases by 3 dBAns: (c)

152. Class of operation of power amplifier with transistor conduction for a period much smallerthan half cycle input signal is Class C.

153. Class C amplifiers are used as Tuned amplifiers.

88) Slope of gain curve of an amplifier beyond11 thehigher cut frequency is

(a) 6db/decade (b) -20db/decade(c) 20db/decade (d) -6db/decadeAns: (b)

89) Distortion in amplifiers due to the non-lineardynamic curve of the active device is referred to as

(a) amplitude distortion (b) frequency distortion(c) phase shift distortion (d) delay distortionAns: (a)

90) Differential voltage gain Ad of a difference amplifier with a voltage gain of individualamplifier circuit A1 and A2

(a) A1-A2 (b) (A1+A2)/2(c) (A1-A2)/2 (d) A1+A2Ans: (c)



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91) Cc is the capacitance of the reverse biased collector base junction and is therefore

(e) independent of collector current(f) mainly transistor capacitance(g) much larger than Ce(h) mainly diffusion capacitanceAns: (b)

92) Cross over distortion in class B amplifier is due to(a) finite cut-off voltage of the two transistors(b) non-identical behaviour of the two transistors(c) elimination of two power supplies in the circuit(d) elimination of even harmonics in the o/pimpedanceAns: (a)93) Large i/p impedance and small o/p impedance are possible inAns) common collector amplifier

94) Identify the correct statement with reference to class B amplifierAns) Even harmonics are cancelled in the ……

95) CE amplifier is characterized byAns) moderate i/p impedance

96) Phase relationship between o/p and i/p voltage of a CS amplifier for frequency below lowercut-off frequency is

(e) both are in phase(f) o/p lags i/p(g) output leads i/p(h) both are 180 out of phaseAns: (c)

97) Identify correct statementsAns) Gain and Bandwidth change such that product is same

98) Cascading of two identical amplifiers with individual gains of 100results inAns) overall gain of 8db

99) Resultant phase shift of 6 common source amplifier stages cascaded at mid band frequency isAns) 180

100) Major advantage of boot strap Darlington pair over single Darlington pair is



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(e) high overall Av with proper DC biasing(f) increased Ai irrespective of bias condition(g) high i/p impedance irrespective of bias condition(h) increased Ai depending upon the bias conditionAns: (c)

101) The frequency up to which hybrid п model is valid is

(a) 3ft (b) 2ft (c) ft/3 (d) ft/2Ans: (c)

102) Identify correct statement in the following statements

(e) for wide brand operation RL ≤2kΩ(f) the band width of CE amplifier is dependent on the load resistance RL(g) At high frequency o/p conductance are generally negligible compared to RL(h) For wide band operation RL >>2kΩAns: (a)

103) The location of operation point of a class A amplifier isAns) active region

104) Total harmonic distortion is maximum inAns) class C

105) Effect of small value of unbiased emitter resistance in CE amplifier is

(e) Increase in voltage gain at mid band frequency(f) Decrease in Av at high frequency(g) Nothing on voltage gain at mid band frequency(h) Decrease in Av at mid band frequencyAns: (d)

106) The mid band gain of BJT is 200 and its bandwidth is 1MHz .If circuit parameters arechanged such that the gain reduces to 10,the bandwidth coil

(a) remains same (c) also reduces to 1/10th

(c) increases to 20MHz (d) increases to 10 MHzAns: (c)

107) Resultant phase shift of five CE emitter amplifier stages cascaded at mid band frequenciesis



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(a) 360 (b) 180 (c) 45 (d)90Ans: (b)

108) Typical value of gm of Ge BJT at room temperature and Ic=1.3mA is

(a) 50mA/volt (b) 1000Ω (c) 80kΩ (d) 4MΩAns: (a)

109) [hie – gm/hfe] represent hybrid п conductance

(e) Feed back conductance gb′c(f) Base spreading conductance gbb′(g) o/p conductance gce(h) i/p conductance gb′c

Ans: (b)

110) Frequency response of an amplifier is defined as

(b) variation of amplifier frequency as a functionof its voltage gain

(b) variation of magnitude of voltage gain as afunction of phase of the voltage gain

(c) variation of magnitude and phase of voltagegain with variation in signal frequencies

(d)variation of amplifier frequency as a function of the phase of its voltage gainAns: (c)

111) Critical capacitance along the smallest equivalent resistance that determines the lowercut-off frequency of a common drain amplitude is

(e) C1,input coupling capacitor(f) Cs,source by pass capacitor(g) Cs,source by pass capacitor ,only if C1=C2(h) C2,output coupling capacitorAns: (d)

112) Resultant upper-cut-off frequency of two identical stages cascaded with individual uppercut-off frequency of 10 KHz is

(a) 6.4 KHz (b) 15.625KHz (c) 10 KHz (d) 5 KHzAns: (a)



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113) In a two stage BJT cascade amplifier

(e) I/P resistance is comparable with hie of a singleCE stage

(f) O/P resistance is as low as hoe of a single CEStage

(g) Reverse voltage gain is much larger than hre of aSingle CE stage

(h) Forward current gain is much smaller than hfe ofSingle CE stageAns: (c)

114) Typical value of rb′c of Ge BJT at room temper--ture and Ic=1.3mA is(a) 1000Ω (b) 4MΩ (c) 100Ω (d) 80KΩAns: ( b)115) Identify the conductance that is not included in hybrid п- model(a) Base emitter conductance, gbe(b) O/P conductance, gce(c) Feed back conductance,gb′c(d) I/P conductance, gb′cAns: (a)

116) Class C amplifier find applications in thefollowing

(e) amp modulation circuits(f) driving loud speakers(g) switching devices(h) comparatorsAns: (a)

117) Mid frequency amplifier range of an amplifier is defined as those frequencies more than 10times that of lower frequencies and less than 0.1 times that of higher frequency in amplifier doesnot have any mid frequency range if

(a) fH<100fL (b) f<0.01f (c) fH >100fL (d) f>100fLAns: (a)

118) The mid band voltage gain of an amplifier with band width of 1MHz is 10db,if the circuitcomponents are changed such that the gain becomes 7db ,its bandwidth becomes

(a) 700 KHz (b) 2 MHz (c) 500 KHz (d) 1 MHzAns: (b)



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119) Resultant voltage gain and phase shift in an n-stage cascaded amplifier with individualgains, A1, A2, A3 …An and phase shifts ө1, ө2 …өn is(a) Ar=A1.A2.A3……..An and ө=ө1+ө2+……. +өn(b) Ar=A1.A2…………An and ө=ө1.ө2…………өn(c) Ar=A1+A2+………+An and ө=ө1.ө2………..өn(d) Ar=A1+A2+……….+An and ө=ө1+ө2+…….+өnAns: (a)120) Break frequency is the frequency at which the capacitive reactance (Xc) and equivalentresistance (Req) at a point of connection in a circuit have following relation

(a) Xc<<Req (b) Xc=Req=∞ (c) Xc=Req (d) Xc>>ReqAns: (c)121) Basic advantage of DC of amplifier stage is

(e) Ability to provide impedance matching(f) Ability to provide very small mid band region(g) Ability to provide narrow and resonant type of frequency response(h) Ability to amplify DC and very low frequency signalAns: (d)

122) Two stage common emitter amplifier configuration with emitters tied together, i/p’s at basesand o/p’s at collectors is called as

(a) Differential pair (b) Cascode amplifier(c) Boot strap Darlington pair (d) Darlington pairAns: (a)

123) Effect of resistor N/W for biasing theDarlington resistorAns) Reduction in overall I/P impedance

124) If a power transistor conducts only during +ve half cycle of i/p signal , the class of operationof the amplifiers isAns) Class B

125) Max conversion efficiency of a Class B power amplifier isAns) 78.5%

126) If the signal voltages and currents at the i/p of a transistor amplifier are within 1/10th of DCoperating point values then transistor is said to be insmall signal mode

127) Phase reversal between O/P and I/P voltages in a CE amplifier occurs at(a) mid band frequency (b) high cut off frequency(c) all the frequency (d) lower cut off frequency



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128) Resonant peak in the frequency response occurs in(a) DC coupling (b) RC coupling(c) direct coupling (d) Transformer coupling

129. If 2 signals of some amplitude and frequency are applied to a differential amplifier theoutput is mainly due to the phase difference between the input signals

130. The output conductance gb’e in terms of low frequency h parameter is given by αD / hfe Re .

131. If power transistor conducts for the entire cycle of input signal , the mode of power amplifieris Class A.

132. Identify the incorrect statement with reference to Class B amplifierAns: A phase inversion is not required at input in Push Pull Amplifier.

133. Doubling the voltage gain of an amplifier results in increase of voltage gain in dB by 3.01.

134. To obtain a constant and high value of voltage gain at midband frequency in CE AmplifierCE should be large enough such that Xce<<RE at midband frequencies.

135. A differential amplifier cannot be considered as ground input ,single ended output.

136. Cross over distortion in Class B amplifier is due to finite cut-in voltage of 2 transistors.

137. If there are 2 uncoupled high pass filter sections in the equivalent circuit of an amplifierwith fL1 and fL2 as cutoff frequency , then the overall lower cutoff frequency of the amplifierapproximately isa) fL2 - fL1b) smaller of fL2 and fL1c) fL2 + fL1d) Larger of fL2 and fL1 , if fL2 and fL1 differ by more than a decade.

138. The phase relationship between output and input voltages of a CS amplifier for frequencyabove higher cut off frequency isa) both are 180 degrees out of phaseb) output leads inputc) both are in phased) output lags input

139. According to Millers theorem , the inter-electrode capacitance, Ccb for a CE amplifier of gainA results in a Miller output capacitance ofa) Ccb(A-1)/A b) Ccb A/(A-1) c) Ccb(1-A) d) Ccb /(A-1)



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140. If V1 = -V2 = 0.5 V are the two input signals applied to a differential amplifier , identify theincorrect statementa) Common mode voltage is 0b) Differential mode voltage is 1Vc) Differential mode voltage is 0d) Output voltage = Differential mode gain

141. Gain in dB as a negative number indicatesa) an absolute gain less than 20b) an absolute gain less than 1c) an absolute gain less than 0d) Phase reversal between i/p and o/p

142. Crossover distortion in Class B amplifiers can be eliminated by modifying the configurationto Class AB .

143. A voltage gain equal to 0dB of an amplifier corresponds toa) Power gain of 2b) Voltage gain of 2c) Voltage gain of unityd) Power gain of zero

144. Configuration of transistor amplifier that acts as a buffer for impedance matching is

145. Resultant lower and upper cut off frequency f1n and f2n of an n stage cascaded identicalamplifier is

146. A cascode amplifier is a combination of147. Typical value of Cc of high frequency hybrid ∏ model of a BJT is

148. Resultant upper 3dB frequency of ‘n’ identical upper cut off frequency given asa) ( f2 )n

b) f2 √(21/n-1)c) f2 /√(21/n-1)d) f2

149. Base width modulation due to early effect results in variations in collector emitter voltages

150. Input impedance is high and output impedance is low in the following transistorconfigurationsa) CC b) CB c) CC and CB d) CE

151. Identify the correct statement



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a) Change in bandwidth for any change in its gain is always 3dBb) If the gain of an amplifier decreases by 3 dB , its bandwidth remains the same.c) Gain and bandwidth of an amplifier change such that their product always remains the same.d) If the gain of an amplifier increases by 3 dB its bandwidth also increases by 3 dB

152. Class of operation of power amplifier with transistor conduction for a period much smallerthan half cycle input signal is Class C.

153. Class C amplifiers are used as Tuned amplifiers.



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