Spark image

The ability to store charge is called the capacitance of the capacitor.

Capacitance (C) = Charge (Q)/Potential difference (V)

A capacitor has a capacitance of one farad if the potential across it rises by one volt when a charge of one coulomb is placed on it.

Uses of capacitors:
(a) in a camera flash lamp - to store charge
(b) in timing devices - to release the charge at a certain rate
(c) as tuners - variable capacitors in a radio
(d) in a rectified output from a power supply
(e) in switches - to slow down current change and so reduce sparking
(f) in computer memory banks - to store information
© Keith Gibbs 2011