Question

Consider the figure shown below.


If the closed loop gain of the circuit is $\frac{V_o}{V_s}=0.75$. Then the open gain of the op-amp $A_{OL}$ will be
(Assume the op-amp is ideal except finite open loop gain)

• A. $4$
• B. $1$
• C. $3$
• D. $2$

Answer 1

The correct option is C $3$

$A_{CL}=\frac{A_{OL}}{1+A_{OL}.\beta }$
$0.75=\frac{A_{OL}}{1+A_{OL}.\beta }$
$\beta =1$
$\Rightarrow A_{OL}=3$