# Amplifiers with Negative Feedback Multiple Choice Questions (MCQs) & Answers

Amplifiers with Negative Feedback Multiple Choice Questions(MCQs) & Answers Amplifiers with Negative Feedback

# CONCEPTS & THEORIES

amplifiers-with-negative-feedback

A Negative-feedback amplifier is an electronic amplifier that subtracts a fraction of its output from its input, so that negative feedback opposes the original signal.It is the method of feeding a portion of the amplified output to the input but in opposite phase. The applied negative feedback can improve its performance and reduces sensitivity to parameter variations due to manufacturing or environment.
There are two main types of negative feedback circuits. They are −
-Negative Voltage Feedback
-Negative Current Feedback

### Negative Voltage Feedback

In this method, the voltage feedback to the input of amplifier is proportional to the output voltage. This is further classified into two types. They are −
-Voltage-series feedback
-Voltage-shunt feedback

### Negative Current Feedback

In this method, the voltage feedback to the input of amplifier is proportional to the output current. This is further classified into two types.They are −
-Current-series feedback
-Current-shunt feedback

### Effects of negative feedback on an amplifier

The major Effects that are introduced by negative feedback are:
-Reduced sensitivity to changes in open loop gain.
-Increases the bandwidth – While open loop amplifier have high gain, they generally have low bandwidth.
-Increase input impedance and decreases output impedance – Basically makes the amplifier closer to an ideal amplifier
-Decreases the output noise of the amplifier
-Reduces the impact of noise from components inside the loop
-Corrects for non-linearity inside the loop – Distortion is reduced

# Amplifiers with Negative Feedback Multiple Choice Questions(MCQs)& Answers

1 The gain of an amplifier without feedback is 100 db. If a negative feedback of 3 db is applied, the gain of the amplifier will become …………..
A 5 db
B 300 db
C 103 db
D 97 db

2 The gain of an amplifier with feedback is known as ………….. gain
A Resonant
B Open loop
C Closed loop
D None of the above

3 A Negative-feedback amplifier is an …….. amplifier.
A Magnetic
B Electronic
C Electromagnetic
D None of the above

4 The voltage gain of an emitter follower is ………..
A Much less than 1
B Approximately equal to 1
C Greater than 1
D None of the above

5 The output impedance of an emitter follower is ……….
A High
B Very high
C Almost zero
D Low

6 Emitter follower is used for …………
A Current gain
B Impedance matching
C Voltage gain
D None of the above

7 If the feedback fraction of an amplifier is 0.01, then voltage gain with negative feedback is approximately………..
A 500
B 100
C 1000
D 5000

8 Emitter follower is a ……………….. circuit
A Voltage feedback
B Current feedback
C Both voltage and current feedback
D None of the above

9 When a negative voltage feedback is applied to an amplifier, its bandwidth……….
A Is increased
B Insufficient data
C Is decreased
D Remains the same

10 When current feedback (negative) is applied to an amplifier, its input impedance …………..
A Remains the same
B Is decreased
C Is increased
D None of the above

11 The value of negative feedback fraction is always …………….
A Less than 1
B More than 1
C Equal to 1
D None of the above

12 An emitter follower has ………… input impedance
A Zero
B Low
C High
D None of the above

13 If voltage feedback (negative) is applied to an amplifier, its output impedance …………..
A Remains the same
B Is increased
C Is decreased
D None of the above

14 When current feedback (negative) is applied to an amplifier, its output impedance ……..
A Is increasedIs increased
B Is decreased
C Remains the same
D None of the above

15 Negative feedback is employed in ……………..
A Amplifiers
B Rectifiers
C Oscillators
D None of the above

16 When voltage feedback (negative) is applied to an amplifier, its input impedance ………….
A Is increased
B Is decreased
C Remains the same
D None of the above

17 A feedback circuit usually employs ……………… network
A Capacitive
B Resistive
C Inductive
D None of the above

18 If the output of an amplifier is 10 V and 100 mV from the output is fed back to the input, then feedback fraction is ………..
A 10
B 1
C 01
D 15

19 When negative voltage feedback is applied to an amplifier, its voltage gain ……………….
A Is increased
B Is reduced
C Remains the same
D None of the above