An operational amplifier (" op amp "for short) is a circuit unit with a very high magnification. In actual circuits, it is usually combined with feedback networks to form a certain functional module. It is an amplifier with a special coupling circuit and feedback. Its output signal can be the result of mathematical operations such as addition, subtraction, differentiation or integration of the input signal. It was named "operational amplifier" because it was initially applied in analog computers to perform mathematical operations.