Question

Consider the amplifier circuit shown in the figure below:

The closed loop gain $A_{CL}$ is equal to -10, then the value of open-loop gain $A_{OL}$ for the op-amp is equal to ______

• A. 109

Answer 1

The correct option is A 109
Thus, $A_{CL}=\frac{-A_{OL}\times K}{1+\beta A_{OL}}wherek=\frac{R_2}{R_1+R_2}=\frac{100}{109}and\beta =\frac{R_1}{R_1+R_2}=\frac{9}{109}-10=\frac{-A_{OL}\times \frac{100}{109}}{1+A_{OL}\times \frac{9}{109}}10=\frac{100A_{OL}}{109+A_{OL}}{A}_{OL}=109$