capacitor

ca·pac·i·tor   (kə-pās'ĭ-tər)    (click for larger image in new window) n.  An electric circuit element used to store charge temporarily, consisting in general of two metallic plates separated and insulated from each other by a dielectric. Also called condenser.

capacitor [(kuh-pas-i-tuhr)]

A device used in electrical circuits. The capacitor stores an electrical charge for short periods of time, and then returns it to the circuit.

Main Entry: ca·pac·i·tor
Pronunciation: k&-'pas-&t-&r
Function: noun
: a device giving capacitance and usually consisting ofconducting plates or foils separated by thin layers of dielectric (as air or mica) with the plates on opposite sides of the dielectric layers oppositely charged by a source of voltage and theelectrical energy of the charged system stored in the polarized dielectric

capacitor electronics
An electronic device that can store electrical charge. The charge stored Q in Coulombs is related to the capacitance C in Farads and the voltage V across the capacitor in Volts by Q = CV.
The basis of a dynamic RAM cell is a capacitor. They are also used for power-supply smoothing (or "decoupling"). This is especially important in digital circuits where a digital device switching between states causes a sudden demand for current. Without sufficient local power supply decoupling, this current "spike" cannot be supplied directly from the power supply due to the inductance of the connectors and so will cause a sharp drop in the power supply voltage near the switching device. This can cause other devices to malfunction resulting in hard to trace glitches.
(1995-04-12)