What does a capacitor do in an electrical circuit?

A capacitor plays a vital role in an electrical circuit by temporarily storing electrical energy. It consists of two conductive plates separated by an insulating material, known as a dielectric. When a voltage is applied across the plates, an electric field develops, and electrical energy is stored as a result of the separation of positive and negative charges. This stored energy can then be released back into the circuit when required, which makes capacitors essential in applications like power supply smoothing, signal coupling, and timing circuits.

The ability to store energy makes capacitors particularly useful in stabilizing voltage and filtering out noise in power systems. They can rapidly charge and discharge, allowing them to maintain performance under varying electrical loads. This characteristic distinguishes them from other components such as resistors or inductors, which have different functions in a circuit.