A capacitor is an electrical device that stores energy in an electric field. It consists of two conductors separated by an insulator. When a capacitor is charged, one conductor has a positive charge and the other has a negative charge. The amount of charge stored on a capacitor is proportional to the voltage across the capacitor and the capacitance of the capacitor.
Capacitors are used in a wide variety of electronic circuits. They can be used to store energy, filter out noise, and provide a stable voltage reference. Capacitors are also used in power supplies, timing circuits, and audio filters.