What is the function of a capacitor in an electrical circuit?

A capacitor functions primarily to store and release electrical energy in an electrical circuit. It consists of two conductive plates separated by an insulating material (dielectric). When a voltage is applied across the plates, an electric field is established, causing the capacitor to accumulate charge. This stored energy can be released when the circuit requires it, making capacitors essential for various applications, such as smoothing out fluctuations in power supply, timing applications, and filtering signals.

Capacitors do not generate power; their role is to manage energy within the circuit. They also do not convert AC to DC; that function is typically performed by rectifiers in conjunction with capacitors to smooth the output. Additionally, while they can influence voltage in a circuit, capacitors do not measure voltage directly; measurement requires different instruments such as voltmeters. This clarity on the role of capacitors underscores their importance in electrical systems and various electronic applications.