A device for storing electric charge. The simplest sort of capacitors consists of two parallel, conductive plates having equal amounts of opposite charges and separated by a → dielectric material. When a capacitor is fully charged there is a → potential difference between its plates. The larger the area of the plates and/or the smaller the separation between them the greater will be the charge that the capacitor can hold and the greater will be its → capacitance. The actual charge Q on the plates of a capacitor is given by: Q = C . V, where C is the capacitance and V the → voltage.