Capacitor

A capacitor is a element in an electrical circuit which stores charge (electrons).

When voltage is first applied to a capacitor, current flows as electrons move into the capacitor. Depending on the size of the capacitor, this will continue for a period, and then tail off, as the capacitor fills up.

Unlike resistors, capacitors show infinite impedance to direct current; to alternating current, their response depends on the frequency - high frequency signals can pass through a capacitor, but not low frequency. The larger the capacitor, the lower the frequencies which can pass through it.

See also

• Resistor
• Inductor