# Amplifiers MCQ’s

This set of Electronic Devices & Circuits Multiple Choice Questions & Answers (MCQs) focuses on “Amplifiers”.

1. In order to prevent distortion in the output signal after amplification, the input signal must be
a) Higher than the positive saturation level of the amplifier
b) Lower than the negative saturation level of the amplifier
c) Must lie with the negative and the positive saturation level of the amplifier
d) Both higher than the positive saturation level of the amplifier and lower than the negative saturation level of the amplifier

2. The voltage gain of the amplifier is 8 and the current gain is 7. The power gain of the amplifier is
a) 56 db
b) 17.481 db
c) 34.963 db
d) 1 db

3. An amplifier operating from ±3V provide a 2.2V peak sine wave across a 100 ohm load when provided with a 0.2V peak sine wave as an input from which 1.0mA current is drawn. The average current in each supply is measured to be 20mA. What is the amplifier efficiency?
a) 20.2%
b) 25.2%
c) 30.2%
d) 35.2%

4. Statement 1: Voltage gain of -5 means that the output voltage has been attenuated.
Statement 2: Voltage gain of -5db means that the output voltage has been attenuated.
a) Statement 1 and Statement 2 are true
b) Statement 1 and Statement 2 are false
c) Only Statement 1 is true
d) Only Statement 2 is true

5. Symmetrically saturated amplifiers operating in clipping mode can be used to convert a sine wave to a
a) Square wave
b) Pseudo Square wave
c) Sawtooth wave
d) Triangular wave

6. If Av, Ai and Ap represents the voltage gain, current gain and power gain ratio of an amplifier which of the below is not the correct expression for the corresponding values in decibel?
a) Current gain: 20 log Ai db
b) Voltage gain: 20 log Av db
c) Power gain: 20 log Ap db
d) Power gain: 10 log Ap

7. Which of the following isn’t true?
a) Both transformer and amplifier can provide voltage gain
b) Both transformer and amplifier can provide current gain
c) Both transformer and amplifier can provide power gain
d) None of the mentioned

8. What is meant by stability of the an amplified signal?
a) The amplified signal must have a finite amplitude
b) The amplified signal should not have self oscillation
c) The input and the output signal must be proportional
d) The ratio of the input and the output signal must be finite

9. An amplifier has a voltage gain of 100 V/V and a current gain of 1000A/A. the value of the power gain decibel is
a) 30 db
b) 40 db
c) 50 db
d) 60 db

10. The units of voltage gain is
a) It has no units, it is a ratio
b) Decibels (db)
c) All of the mentioned
d) None of the mentioned