When a transistor is cut off _________________?

Maximum voltage appears across transistor

Maximum voltage appears across load

An AF amplifier is shielded to ________________?

Prevent induction due to stray magnetic fields

35 + Mcqs in Transistor Audio Power Amplifiers in Electrical Engineering Questions Page 1 McqOptions

1.	When a transistor is cut off _________________?
A.	Maximum voltage appears across transistor
B.	Maximum current flows
C.	Maximum voltage appears across load
D.	None of the above
Answer» B. Maximum current flows

Discussion

2.	What will be the collector efficiency of a power amplifier having zero signal power dissipation of 5 watts and a.c. power output of 2 watts ?
A.	20%
B.	80%
C.	40%
D.	50%
Answer» D. 50%

Discussion

3.	What turn ratio (Np/Ns) of transformer is required to match 4 O speaker to a transistor having an output impedance of 8000 O ?
A.	2
B.	7
C.	3
D.	None of the above
Answer» C. 3

Discussion

4.	Transformer coupling can be used in______________amplifiers?
A.	Either power or voltage
B.	Only power
C.	Only voltage
D.	None of the above
Answer» B. Only power

Discussion

5.	The size of a power transistor is made considerably large to________________?
A.	Provide easy handling
B.	Dissipate heat
C.	Facilitate connections
D.	None of the above
Answer» C. Facilitate connections

Discussion

6.	The push-pull circuit must use ______________ operation?
A.	Class A
B.	Class C
C.	Class B
D.	Class AB
Answer» D. Class AB

Discussion

7.	The pulsating d.c. applied to power amplifier causes________________?
A.	Burning of transistor
B.	Hum in the circuit
C.	Excessive forward voltage
D.	None of the above
Answer» C. Excessive forward voltage

Discussion

8.	The output transformer used in a power amplifier is a _____________ transformer?
A.	1:1 ratio
B.	Step-up
C.	Step-down
D.	None of the above
Answer» D. None of the above

Discussion

9.	The output stage of a multistage amplifier usually employs _________________?
A.	Push-pull amplifier
B.	Preamplifier
C.	Class A power amplifier
D.	None of the above
Answer» B. Preamplifier

Discussion

10.	The output stage of a multistage amplifier usually employs______________?
A.	Push-pull amplifier
B.	Preamplifier
C.	Class A power amplifier
D.	None of the above
Answer» B. Preamplifier

Discussion

11.	The output stage of a multistage amplifier is also called _________________-?
A.	Mixer stage
B.	Power stage
C.	Detector stage
D.	F stage
Answer» C. Detector stage

Discussion

12.	The output signal voltage and current of a power amplifier are 5V and 200 mA; the values being r.m.s. What is the power output ?
A.	1 W
B.	2 W
C.	4 W
D.	None of the above
Answer» B. 2 W

Discussion

13.	The most important consideration in power amplifier is __________________?
A.	Biasing the circuit
B.	Collector efficiency
C.	To keep the transformer cool
D.	None of the above
Answer» C. To keep the transformer cool

Discussion

14.	The most costly coupling is _______________ coupling?
A.	RC
B.	Direct
C.	Impedance
D.	Transformer
Answer» E.

Discussion

15.	The maximum efficiency of resistance loaded class A power amplifier is _________________?
A.	5%
B.	50%
C.	30%
D.	25%
Answer» E.

Discussion

16.	The maximum efficiency of transformer coupled class A power amplifier is _______________?
A.	30%
B.	50%
C.	80%
D.	45%
Answer» C. 80%

Discussion

17.	The maximum collector efficiency of class B operation is ________________?
A.	50%
B.	90%
C.	15%
D.	5%
Answer» E.

Discussion

18.	The driver stage usually employs_________________?
A.	Class A power amplifier
B.	Push-pull amplifier
C.	Class C amplifier
D.	None of the above
Answer» B. Push-pull amplifier

Discussion

19.	The disadvantage of impedance matching is that it _______________?
A.	Gives distorted output
B.	Gives low power output
C.	Requires a transformer
D.	None of the above
Answer» B. Gives low power output

Discussion

20.	The class B push-pull circuit can deliver 100 W of a.c. output power. What should be the minimum power rating of each transistor ?
A.	20 W
B.	40 W
C.	10 W
D.	80 W
Answer» B. 40 W

Discussion

21.	Power amplifiers handle ______________ signals compare to voltage amplifiers?
A.	Small
B.	Very small
C.	Large
D.	None of the above
Answer» D. None of the above

Discussion

22.	Power amplifiers generally use transformer coupling because transformer permits______________?
A.	Cooling of the circuit
B.	Impedance matching
C.	Distortionless output
D.	Good frequency response
Answer» C. Distortionless output

Discussion

23.	Low efficiency of a power amplifier results in_________________?
A.	Low forward bias
B.	Less battery consumption
C.	More battery consumption
D.	None of the above
Answer» D. None of the above

Discussion

24.	In class A operation, the operating point is generally located_____________of the d.c. load line?
A.	At cut off point
B.	At the middle
C.	At saturation point
D.	None of the above
Answer» C. At saturation point

Discussion

25.	If the zero signal dissipation of a transistor is 1W, then power rating of the transistor should be at least___________________?
A.	5 W
B.	33 W
C.	75 W
D.	1 W
Answer» E.

Discussion

26.	If the power rating of a transistor is 1W and collector current is 100mA, then maximum allowable collector voltage is________________?
A.	1V
B.	100V
C.	20V
D.	10V
Answer» E.

Discussion

27.	If the gain versus frequency curve of a transistor amplifier is not flat, then there is distortion ?
A.	Amplitude
B.	Intermodulation
C.	Frequency
D.	None of the above
Answer» D. None of the above

Discussion

28.	If a transistor is operated in such a way that output current flows for 60o of the input signal, then it is ______________ operation?
A.	Class A
B.	Class B
C.	Class C
D.	None of the above
Answer» D. None of the above

Discussion

29.	________________ coupling is generally employed in power amplifiers?
A.	Transformer
B.	RC
C.	direct
D.	Impedance
Answer» B. RC

Discussion

30.	Class_____________ power amplifier has the highest collector efficiency ?
A.	C
B.	A
C.	B
D.	AB
Answer» B. A

Discussion

31.	Class _____________ operation gives the maximum distortion?
A.	A
B.	B
C.	C
D.	AB
Answer» D. AB

Discussion

32.	Class C amplifiers are used as ___________________?
A.	AF amplifiers
B.	Detectors
C.	amplifiers
D.	None of the above
Answer» D. None of the above

Discussion

33.	An AF amplifier is shielded to ________________?
A.	Keep the amplifier cool
B.	Protect from rusting
C.	Prevent induction due to stray magnetic fields
D.	None of the above
Answer» D. None of the above

Discussion

34.	A transformer coupled class A power amplifier has a load of 100 O on the secondary. If the turn ratio is 10:1, what is the value of load appearing on the primary?
A.	5 kO
B.	20 kO
C.	100 kO
D.	10 kO
Answer» E.

Discussion

35.	A power amplifier has comparatively __________________ ß ?
A.	Small
B.	Large
C.	Very large
D.	None of the above
Answer» B. Large

Discussion

Explore topic-wise MCQs in Electrical Engineering Questions.

When a transistor is cut off _________________?

What will be the collector efficiency of a power amplifier having zero signal power dissipation of 5 watts and a.c. power output of 2 watts ?

What turn ratio (Np/Ns) of transformer is required to match 4 O speaker to a transistor having an output impedance of 8000 O ?

Transformer coupling can be used in______________amplifiers?

The size of a power transistor is made considerably large to________________?

The push-pull circuit must use ______________ operation?

The pulsating d.c. applied to power amplifier causes________________?

The output transformer used in a power amplifier is a _____________ transformer?

The output stage of a multistage amplifier usually employs _________________?

The output stage of a multistage amplifier usually employs______________?

The output stage of a multistage amplifier is also called _________________-?

The output signal voltage and current of a power amplifier are 5V and 200 mA; the values being r.m.s. What is the power output ?

The most important consideration in power amplifier is __________________?

The most costly coupling is _______________ coupling?

The maximum efficiency of resistance loaded class A power amplifier is _________________?

The maximum efficiency of transformer coupled class A power amplifier is _______________?

The maximum collector efficiency of class B operation is ________________?

The driver stage usually employs_________________?

The disadvantage of impedance matching is that it _______________?

The class B push-pull circuit can deliver 100 W of a.c. output power. What should be the minimum power rating of each transistor ?

Power amplifiers handle ______________ signals compare to voltage amplifiers?

Power amplifiers generally use transformer coupling because transformer permits______________?

Low efficiency of a power amplifier results in_________________?

In class A operation, the operating point is generally located_____________of the d.c. load line?

If the zero signal dissipation of a transistor is 1W, then power rating of the transistor should be at least___________________?

If the power rating of a transistor is 1W and collector current is 100mA, then maximum allowable collector voltage is________________?

If the gain versus frequency curve of a transistor amplifier is not flat, then there is distortion ?

If a transistor is operated in such a way that output current flows for 60o of the input signal, then it is ______________ operation?

________________ coupling is generally employed in power amplifiers?

Class_____________ power amplifier has the highest collector efficiency ?

Class _____________ operation gives the maximum distortion?

Class C amplifiers are used as ___________________?

An AF amplifier is shielded to ________________?

A transformer coupled class A power amplifier has a load of 100 O on the secondary. If the turn ratio is 10:1, what is the value of load appearing on the primary?

A power amplifier has comparatively __________________ ß ?