Capacitors

A capacitor (also known as a condenser) is a passive electronic component used to store and release electrical energy within a circuit. It consists of two conductive plates separated by an insulating material known as the dielectric. When a voltage is applied across the plates, an electric field develops, causing positive charge to build up on one plate and negative charge on the other. This stored energy can then be discharged as needed, making capacitors essential for functions such as filtering, energy storage, signal processing, coupling, tuning, rectification, and power conditioning.

Capacitors are found in nearly all electronic and electrical circuits. The conductive plates are typically made of thin aluminum foil, while the dielectric may be composed of materials such as paper, Mylar, polypropylene, ceramic, mica, or even air. In electrolytic capacitors, the dielectric is a layer of aluminum oxide that is formed through the application of voltage after assembly. The performance and characteristics of a capacitor depend on the materials used, as well as the thickness of the dielectric and the physical spacing between the conductive plates.