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1) 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 = c2

c) c2 output coupling capacitor d) None.

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

b) class A mode c) class AB mode d) 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 transistor d) 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 follower b) 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 are a) both zero

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

8) the miller input capacitance in CB AMP IS



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

9) identify the correct relationship a) f alpha ~ f beta

b) f beta >> f alpha

c) f alpha ~ ftd) f alpha >> f beta

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

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

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

b) 100c) 50 d) 25

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

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

13) voltage gain of an amplifier reduces to 1/(root 2)its max a) break frequencyb) miller frequencyc) half power frequency d) 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 large c) it decreases with increase in ac load R d) it is always approximately unity

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

b) common drain amplifier



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 circuit b) 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 distortion ans: [D ]

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

a) hfe/2 b) hfe

c) 2hfe d) hfe

2 ans: [ D ]

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

a) zero b) Ad Vd

c) (AdVd+ AcVc)d) AcVc

ans: [ C ]

19) rce >> rbe condition is applicable in hybrid -pie equivalent of CE amplifier because a) 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)



ans:[ D ]

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

a) thermal expansion b) thermal coefficient c) thermal resistance d) thermal powerans : [ A ]

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

a) both transistors are perfectly matched b) both NPN & PNP transistors are usedc) A phase inversion is not used at inputs of 2 transistors d) 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 capacitors b) coupling capacitorsc) blocking capacitorsd) dc de-coupling capacitors ans : [ A ]

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

a) common gate amplifier b) common drain amplifier c) 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)



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

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

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

d) sum of the phase shifts introduced by individual stages ans: [ 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 stage c) 2 capacitively coupled CB stages cascaded.d) 2 capacitively coupled CC stages cascaded ans: [ 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 Ic

c)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 ]



a) 1/(root 2) times Max value b) minc)unityd) constant ans: [ D ]

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

a)common gate amplifierb) common drain amplifier C) common source amplifier d)swamped source resistor amplifier ans:[ A ]

32) 2-transistor cascade with both collectors tied together & emitter of the transistor connected to the base of the transistor isreferred to as

[ a]a) Darlington pair b) CE &CC cascade c) cascade amplifier d) differential pair ans: [ A ]

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

a) zero b) Ad Vd

c)Ad Vd + AcVc

d) AcVc

ans:[ B ]

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

a) Fh - F l

b) Fh/ qc) (Fh-Fl)/1.414 d) q-Fl

ans: [ A ]

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



[ 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) hic

b) hie

c) infinity d) hib

ans: [ B ]

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

a) temperatureb) operation frequency c) CE voltaged) C c

ans : [ 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 value b) frequency at which CE current gain becomes unityc) frequency at which CE voltage gain falls to half its Max value d) 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 capacitor b) c wiringc) external capacitor at the base d)cbe

ans: [ B ]



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

a) a small portion around Q point in active region b) entire portion around Q point in saturationc) entire portion around Q point in cutoff d) entire portion around Q point in active ans: [ 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 cycle d) ensure o/p wave shape to the replica of i/p wave shape ans: [ B ]

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

a) Av- Ai

b) Av/ Ai

c)10log 10 Av/ Ai

d) Av+Ai

ans : [ D ]

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

a) with emitter resistance b) with i/p resistancec) with o/p resistanced) with base resistance ans: [ B ]

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

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



d) no requirement of bulky components all frequency ans: [ 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 follower b) dependence of Av on transistor selectedc) low i/p impedance compared to single emitter follower d) dependence of H -parameters on quiescent conditions ans: [ D ]

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

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

48) main characteristic features of differential amplifier is absence of frequency dependent components

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 emitter voltages

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



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 CE b) is very large because of +ve voltage gain in CB c) is small because of +ve voltage gain in CBd) not negligible compared to other capacitance ans: [ 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 value b)zeroc) always a complex value d) infinityans: [ B ]

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

a) direct coupling b)inductive coupling c) RC couplingd) transistor coupling

ans : [ C ]

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

a) low i/p impedance b) low current gainc) high o/p impedance d)high leakage current ans: [ D ]

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



a) unity b) zero c)100d) infinity

ans: [ D ]

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

a) independent of collector current b) much lager than Cc

c) mainly diffusion capacitanced) mainly transition capacitance ans: [ C ]

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

a) capability to launch heat generated into the surroundings b) deviation in power delivered to load resistorc) capability to withstand the variation in dc power at operating power d) 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 harmonics b) elimination of dc current in the load c) 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 capacitance b) bypass capacitancec) blocking capacitanced ) coupling capacitance ans: [ A ]



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 cutoff frequency is [ b ]

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

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

a) o/p coupling capacitors b) i/p coupling capacitorsc) emitter bypass capacitors d) inter electrode capacitor ans:[ B ]

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

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



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

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

a) phase shift distortion b) amplitude distortion c) frequency distortion d) delay distortionans : [ C ]

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

a) -20 db decade b) 6 db decadec)-6 db decaded) 20 db decade ans : [ A ]

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

a) hfe/1.414 b) unity

c) hfe

d)zero ans: [ D ]

70. The frequency at which CE is short circuit current gain becomes unity is represented by 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 Cl ass B p ush pul l amp li fi er.

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



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

Ans: (b)

75. A CC amplifier is characterized by approximately A)unity power gain b)unity i/p ,o/p impedance ratio c)unity voltage gain d) unity current gain Ans: (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 is a)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 ofa) 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 by a)AI<1 a)AV>1 c) a)AV<1 d) Small Ro

Ans: (c)

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

83. Expression for cut off frequency in hybrid parameters



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

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

Ans: (d)

85. The transformer ratio (N1:N2) necessary to match a 16Ω speaker to an amplifier to obtain an effective 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 the higher cut frequency is

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

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

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

90) Differential voltage gain Ad of a difference amplifier with a voltage gain of individual amplifier 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



(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/p impedanceAns: (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 lower cut-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 condition Ans: (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(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 are changed 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 MHz Ans: (c)

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

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



(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 function of its voltage gain

(b) variation of magnitude of voltage gain as a function of phase of the voltage gain

(c) variation of magnitude and phase of voltage gain 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 lower cut-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 upper cut-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 CE Stage

(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)



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) 80KΩ Ans: ( 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 the following

(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 10 times that of lower frequencies and less than 0.1 times that of higher frequency in amplifier does not have any mid frequency range if

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

118) The mid band voltage gain of an amplifier with band width of 1MHz is 10db,if the circuit components 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 individual gains, 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+…….+өn Ans: (a)120) Break frequency is the frequency at which the capacitive reactance (Xc) and equivalent resistance (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

(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 bases and 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 operation of 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 frequency Ans: (a)

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



Ans: (d)

129. If 2 signals of some amplitude and frequency are applied to a differential amplifier the out p ut i s m a i n l y d ue to the p h a se di ffe r en c e b et w een the i n p ut s i g n a l s

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 amplifier is C l a ss 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 i ncrease of vol tage gai n i n d B by 3.0 1.

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 i np ut ,si ngl e end ed outp ut.

136. Cross over distortion in Class B amplifier is due to fi ni te cut -i n vol tage of 2 tran s i stors.

137. If there are 2 uncoupled high pass filter sections in the equivalent circuit of an amplifier with fL1 and fL2 as cutoff frequency , then the overall lower cutoff frequency of the amplifier approximately isa) fL2 - fL1

b) smaller of fL2 and fL1

c) fL2 + fL1

d) 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 frequency above higher cut off frequency isa) both are 180 degrees out of phase b) output leads inputc) both are in phase d) output lags input Ans: (d)



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 the incorrect 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 indicates a) an absolute gain less than 20b) an absolute gain less than 1 c) 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 configuration to C l a ss AB .

143. A voltage gain equal to 0dB of an amplifier corresponds to a) Power gain of 2b) Voltage gain of 2c) Voltage gain of unity d) 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 identical amplifier 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 as a) ( f2 )n

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

Ans:



149. Base width modulation due to early effect results in va ri ati ons i n col l ector emi tter vol tage s

150. Input impedance is high and output impedance is low in the following transistor configurationsa) CC b) CB c) CC and CB d) CE Ans:

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 smaller than half cycle input signal is C l a ss C .

153. Class C amplifiers are used as T uned a mp li fi ers.

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

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

89) Distortion in amplifiers due to the non-linear dynamic 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 individual amplifier 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

(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/p impedanceAns: (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 lower cut-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



(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 condition Ans: (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 are changed 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 MHz Ans: (c)

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



(a) 360 (b) 180 (c) 45 (d)90 Ans: (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 function of its voltage gain

(b) variation of magnitude of voltage gain as a function of phase of the voltage gain

(c) variation of magnitude and phase of voltage gain 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 lower cut-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 upper cut-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

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

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

(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) 80KΩ Ans: ( 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 the following

(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 10 times that of lower frequencies and less than 0.1 times that of higher frequency in amplifier does not have any mid frequency range if

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

118) The mid band voltage gain of an amplifier with band width of 1MHz is 10db,if the circuit components 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 individual gains, 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+…….+өn Ans: (a)120) Break frequency is the frequency at which the capacitive reactance (Xc) and equivalent resistance (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 bases and 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 operation of 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



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 the out p ut i s m a i n l y d ue to the p h a se di ffe r en c e b et w een the i n p ut s i g n a l s

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 amplifier is C l a ss 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 i ncrease of vol tage gai n i n d B by 3.0 1.

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 i np ut ,si ngl e end ed outp ut.

136. Cross over distortion in Class B amplifier is due to fi ni te cut -i n vol tage of 2 tran s i stors.

137. If there are 2 uncoupled high pass filter sections in the equivalent circuit of an amplifier with fL1 and fL2 as cutoff frequency , then the overall lower cutoff frequency of the amplifier approximately isa) fL2 - fL1

b) smaller of fL2 and fL1

c) fL2 + fL1

d) 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 frequency above higher cut off frequency isa) both are 180 degrees out of phaseb) output leads input c) 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)



140. If V1 = -V2 = 0.5 V are the two input signals applied to a differential amplifier , identify the incorrect 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 indicates a) an absolute gain less than 20b) an absolute gain less than 1 c) 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 configuration to C l a ss AB .

143. A voltage gain equal to 0dB of an amplifier corresponds to a) Power gain of 2b) Voltage gain of 2c) Voltage gain of unity d) 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 identical amplifier 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 as a) ( f2 )n

b) f2 √(21/n-1)c) f2 /√(21/n-1)d) f2

149. Base width modulation due to early effect results in va ri ati ons i n col l ector emi tter vol tage s

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

151. Identify the correct statement



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 smaller than half cycle input signal is C l a ss C .

153. Class C amplifiers are used as T uned a m p li f i e r s .

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