Electronic Devices And Circuits Set 10 MCQs

Q1 | The output of a class-B amplifier

is distortion free

consists of positive half cycle only

is like the output of a full wave rectifier

comprises short duration current pulses

Q2 | Crossover distortion occurs in amplifiers.

push-pull

class a

class b

class ab

Q3 | The main use of a class C amplifier is

as an rf amplifier

as stereo amplifier

in communication sound equipment

as distortion generator

Q4 | The decibel is a measure of

power

voltage

current

sound level

Q5 | The output stage of a multistage amplifier is also called

mixer stage

power stage

detector stage

f stage

Q6 | coupling is generally employed in power amplifiers

transformer

rc

direct

impedance

Q7 | The maximum efficiency of resistance loaded class A power amplifier is

5%

50%

30%

25%

Q8 | Class power amplifier has the highest collector efficiency

c

a

b

ab

Q9 | Power amplifiers handle signals compare to voltage amplifiers.

small

very small

large

none of the above

Q10 | In class B operation, at what fraction of VCC should the level of VL(p) be to achieve the maximum power dissipated by the output transistor?

0.5

0.636

0.707

1

Q11 | In class A operation, the operating point is generally located of the d.c. load line.

at cut off point

at the middle

at saturation point

none of the above

Q12 | The output transformer used in a power amplifier is a transformer.

1:1 ratio

step-up

step-down

none of the above

Q13 | Power amplifiers primarily provide sufficient power to an output load, typically from to .

a few kw, tens of kw

500 w, 1 kw

100 w, 500 w

a few w, tens of w

Q14 | The main feature(s) of a large-signal amplifier is (are) the .

circuit\s power efficiency

maximum amount of power that the circuit is capable of handling

impedance matching to the output

all of the above

Q15 | In power amplifiers, the output signal varies for a full 360º of the cycle.

class a

class b or ab

class c

class d

Q16 | In class B power amplifiers, the output signal varies for of the cycle.

360º

180º

between 180º and 360º

less than 180º

Q17 | amplifiers have the highest overall efficiency.

class a

class b or ab

class c

class d

Q18 | Class D operation can achieve power efficiency of over .

90%

78.50%

50%

25%

Q19 | The beta of a power transistor is generally .

more than 200

100 to 200

less than 100

Q20 | A form of class A amplifier having maximum efficiency of _ uses a transformer to couple the output signal to the load.

90%

78.50%

50%

25%

Q21 | The reflected impedance seen from one side of the transformer to the other side is .

n1/n2

(n1/n2)2

(n1/n2)1/3

n1× n2

Q22 | In a class A transformer-coupled power amplifier, winding resistance of the transformer determine(s) the dc load line for the circuit.

the ac

the dc

both the ac and dc

neither the ac nor dc

Q23 | The slope of the ac load line in the class A transformer-coupled transistor is .

–1/rl (load resistor)

1/(a2rl)

–1/(a2rl)

1/rl

Q24 | The amount of power dissipated by the transistor is the of that drawn from the dc supply (set by the bias point) and the amount delivered to the ac load.

product

difference

average

Q25 | A class A amplifier dissipates power when the load is drawing maximum power from the circuit.

the least

about the same

the most

none of the above