Q. Explain working of Inverting Amplifier?
One common op-amp circuit is shown in Figure. For the case of finite voltage gain Ao of an op amp that is otherwise ideal, the output voltage becomes
which is independent of the op amp's gain A_{o}. The sign inversion associated with Equation makes the amplifier "inverting." Generally if A_{o} is at least 200 times the magnitude of R_{2}/R_{1}, then the actual gain given by Equation will be within 1% of the ideal gain given by Equation. Assuming infinite gain of the op amp, it follows that
v_{d} = v_{2} - v_{1} = 0 or v_{1} = v_{2}
Since terminal 2 is at ground potential (zero) in Figure, terminal 1 is said to be a virtual ground.Notice that when R_{2} =R_{1}, the inverting amplifier becomes a voltage follower with inverted sign and a gain magnitude of unity.