Question

The voltage gain of an amplifier with $9$ % negative feedback is $10.$ The voltage gain without feedback will be:

• A. $1.25$
• B. $100$
• C. $90$
• D. $10$

Answer 1

The correct option is B $100$

Voltage gain $=\frac{A_v}{1+\beta .A_v}$
where $\beta =\frac{9}{100}=0.09$ , voltage gain = 10
$\Rightarrow 10=\frac{A_v}{1+\frac{9}{100}.A_v}$
$\Rightarrow A_v=\frac{10}{0.1}=100$