Basic Op-Amp Circuits - Technical MCQs

Q1:

In the given circuit, VIN1 equals ______.

A +4 V

B +20 V

C –4 V

D –20 V

ANS:C - –4 V

Vo= -Vin*(Rf/Rin) --1

As the inverting input resistors are arranged in parallel
1/Rin= 1/24K + 1/24K+ 1/24K
1/Rin= 3/24K
Rin= 24K/3=8K --2

Apply Rin value in eqn 1

+12= -Vin*(24K/8K)
+12= -Vin*(3)

Hence Vin= -4V