An operational amplifier, commonly referred to as an op-amp, is a high-gain voltage amplifier that enhances the difference between its two input signals.

An op-amp features two inputs—known as the inverting and non-inverting inputs—and a single output. The output voltage is directly proportional to the difference between the voltages at these two inputs, with the gain being determined by the op-amp’s internal circuitry.

The high gain of an op-amp is achieved through a series of amplification stages, which include a differential amplifier, a voltage amplifier, and an output stage. The differential amplifier specifically amplifies the voltage difference between the two inputs. The subsequent voltage amplifier provides an additional layer of gain, while the output stage serves to buffer the output signal and ensure a low output impedance.

Op-amps are versatile components that can be employed in a wide range of applications, such as amplifiers, filters, oscillators, and comparators. They are particularly prevalent in audio processing and signal manipulation circuits, as well as in instrumentation and control systems.

Several critical characteristics define op-amps, including input impedance, output impedance, gain bandwidth product, and slew rate. These parameters significantly influence the performance of the op-amp in various applications and must be carefully evaluated when selecting an op-amp for a specific circuit design.