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Free download in PDF Transistor Audio Power Amplifier Objective Type Questions and Answers for competitive exams. These short objective type questions with answers are very important for Board exams as well as competitive exams. These short solved questions or quizzes are provided by Gkseries.
(21)
The most costly coupling is ……………… coupling
[A]
RC
[B]
Direct
[C]
Impedance
[D]
Transformer
(22)
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
(23)
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: Gives distorted output
(24)
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: Hum in the circuit
(25)
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: Prevent induction due to stray magnetic fields
(26)
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: Collector efficiency
(27)
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
(28)
Transformer coupling can be used in …………… amplifiers
[A]
Either power or voltage
[B]
Only power
[C]
Only voltage
[D]
None of the above
Answer: Either power or voltage
(29)
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: Impedance matching
(30)
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
31
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
32
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
33
The push-pull circuit must use …………… operation
[A]
Class A
[B]
Class C
[C]
Class B
[D]
Class AB
34
For the same a.c. power output as above, what should be the minimum power rating of transistor for class B operation?
[A]
10 W
[B]
4 W
[C]
8 W
[D]
None of the above
35
The maximum a.c. power output from a class A power amplifier is 10 W. What should be the minimum power rating of the transistor used ?
[A]
10 W
[B]
15 W
[C]
5 W
[D]
20 W
36
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
37
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%
38
When no signal is applied, the approximate collector efficiency of class A power amplifier is …….
[A]
10%
[B]
0%
[C]
25%
[D]
50%
39
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
40
The driver stage usually employs………….
[A]
Class A power amplifier
[B]
Push-pull amplifier
[C]
Class C amplifier
[D]
None of the above
Answer: Class A power amplifier
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