GATE 2022 IN – Question 35
An OPAMP with gain $10^4$, input impedance 10 M$\Omega$, and output impedance 100 $\Omega$ is used in a unity-gain feedback voltage buffer. Its closed-loop output impedance is ______ m$\Omega$ (one decimal place).
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Show answer and explanation
Correct answer: 9.9 to 10.0
Explanation
Unity voltage feedback reduces output impedance by 1+Aβ=10001.
Thus Zout=100/10001 Ω=9.999 mΩ, rounding to **10.0 mΩ**.