Question

6. the voltage gain of an amplifier is 100. when negative feedback with feedback ratio 0.04 is applied the gain
becomes
(A) 0.4
(B) 2.
(C) 4
(D) 20​

Answer 1

Answer:

ammeter

An ammeter is a measuring device used to measure the electric current in a circuit. A voltmeter is connected in parallel with a device to measure its voltage, while an ammeter is connected in series with a device to measure its current.

Answer 2

Given:

Voltage gain of an amplifier without feedback (Av) = 100

Feedback fraction (mv) = 0.04

To find:

The voltage  gain of the amplifier if negative voltage feedback is introduced in the circuit.

Solution:

$A_v_f = \frac{A_v}{1+A_vm_v}$

$A_v_f = \frac{100}{1+(100)(0.04)}$

$A_v_f = \frac{100}{1+4}$

Avf = 100 / 5

Avf = 20

Therefore, the voltage  gain of the amplifier if negative voltage feedback is introduced in the circuit is 20.

So, option (D) is correct

(D) 20