Inverting Op-AmpThe open loop gain(Ao) of the Om-Apm is very high which makes it very unstable, so to make it stable with a controlable gain, a feed back is applied through some external resistor(Rf) from its output to inverting input terminal(i.e.,also known as negative feedback) resulting in reduced gain(closed loop gain, Av).
So the voltage at inverting terminal is now the sum of the actual input and feedback voltages, and to separate both a input resistor(Ri) is introduced in the circuit. The non inverting terminal of the opamp is grounded, and the inverting terminal behaves like a virtual ground as the junction of the input and feedback signal are at the same potential.
@BasicElectronics
