Explain virtual ground concept with respect to op-amp.

1.	Explain virtual ground concept with respect to op-amp.
Answer» If V_A and V_B are the voltages at inverting and non-inverting terminals, then open-loop gain. A = \(\frac{V_o}{V_B-V_A}\) = ∞ ∴ V_B - V_A = 0 (or) V_A = V_B As V_B = 0 (as non-inverting terminal is grounded), V_A= 0. Zero voltage at the inverting terminal is called virtual ground.

Answer»

If V_A and V_B are the voltages at inverting and non-inverting terminals, then open-loop gain.

A = \(\frac{V_o}{V_B-V_A}\) = ∞

∴ V_B - V_A = 0

(or) V_A = V_B

As V_B = 0 (as non-inverting terminal is grounded), V_A= 0.
Zero voltage at the inverting terminal is called virtual ground.

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