A capacitor is an electrical component which can temporarily store electrical energy within an electric field.
All capacitors are constructed with at least two electrical conductors separated by a dielectric material.
This is an insulator which polarises the energy from the conductors to reduce the overall internal field. Materials used as insulators include glass, plastic, paper, film and ceramic for example.
Capacitors are regularly used in electronic circuits in order to block direct current (DC) whilst simultaneously allowing alternating current (AC) to pass. Alternating current can reverse direction in contrast to the one way flow of direct current.