A differential amplifier is a type of electronic amplifier that amplifies the difference between two input voltages only. The differential amplifier two inputs are the inverting input and non-inverting input. Its output signal is 180° out of phase with inverting input signal and in phase with non-inverting input signal.
The different modes of operation of the differential amplifier are:
The circuit below shows the differential amplifier with a large differential input signal. When an Operational Amplifier (OPAMP) is used in this configuration it is also called a comparator.