Question

Virtual ground of an op-amp means:

• A. Terminal is grounded directly
• B. The terminal is not physically grounded but terminal voltage is zero due to the other terminal is connected to the ground due to op-amp properties.
• C. Both (a) and (b)
• D. None of the above

Answer 1

The correct option is B The terminal is not physically grounded but terminal voltage is zero due to the other terminal is connected to the ground due to op-amp properties.

A virtual ground is a node of a circuit that is at a steady reference potential, without being directly connected to the reference potential.

2. It is a concept that made for easy explanation and calculation purpose as voltage is approximately zero.

In an ideal Op-amp

Gain$=\frac{V_o}{V_{in}}$

As gain is infinite $V_{in}=0$

$\to V_{in}=V_z-V_1$

In the above circuit $V_1$ is connected to ground so, $V_1=0$ Thus $V_2$ also will be at ground potential.

$i.e.V_2=0$