What is the characteristic function of a Differential Op Amp?

The characteristic function of a Differential Operational Amplifier is that it amplifies only the difference between two input voltages. This is a fundamental property of differential amplifiers, allowing them to effectively reject any signals that are common to both inputs, which is known as common-mode rejection. This capability makes differential op-amps particularly useful in applications such as instrumentation and signal processing, where it is crucial to extract the desired differential signal while minimizing the effects of noise and interference that may be present on both inputs.

By only amplifying the difference, the differential op-amp enhances the accuracy and fidelity of the output in relation to the signals being measured, thus serving its primary function effectively.