GATE 2025 EE – Question 56
The op-amps in the following circuit are ideal. The voltage gain of the circuit is _____ (round off to the nearest integer).
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Correct answer: 2
Explanation
Let the terminals be $V_-$ (at the first non-inverting input) and $V_+$ (at the second), so $V_{in}=V_+-V_-$. Stage 1 is a non-inverting amplifier with two 10 kΩ resistors: $V_{o1}=2V_-$. Stage 2 has $V_{o1} o10 ext{ k}Omega o$ inverting node and a 10 kΩ feedback, with $V_+$ at its non-inverting input: $V_{out}=left(1+ frac{10}{10}
ight)V_+- frac{10}{10}V_{o1}=2V_+-2V_-=2V_{in}$. The voltage gain is 2.