Question

Consider the feedback ampllfier shown in the figure below:

Assume the amplifier to be ideal, then the value of overall voltage gain with feedback Avf is equal to___.

• A. 19.61

Answer 1

The correct option is A 19.61
The voltage gain, $A_v=\frac{1}{1\times {10}^{-3}}=1000$

now, $V_f=V_0\left[\frac{1}{1+19}\right]=\frac{V_0}{20}$

$\frac{V_f}{V_0}=\beta =\frac{1}{20}$

$\therefore \frac{V_0}{V_i}=\frac{A_f}{1+A_f\beta }=\frac{{10}^3}{1+\frac{1000}{20}}=19.61$