Capacitance

Common symbols
C
SI unitfarad
Other units
μF, nF, pF
In SI base unitsF = A2 s4 kg−1 m−2
Derivations from
other quantities
C = charge / voltage
Dimension

Capacitance is the capacity of a material object or device to store electric charge. It is measured by the charge in response to a difference in electric potential, expressed as the ratio of those quantities. Commonly recognized are two closely related notions of capacitance: self capacitance and mutual capacitance.[1]: 237–238  An object that can be electrically charged exhibits self capacitance, for which the electric potential is measured between the object and ground. Mutual capacitance is measured between two components, and is particularly important in the operation of the capacitor, an elementary linear electronic component designed to add capacitance to an electric circuit.

The capacitance between two conductors depends only on the geometry; the opposing surface area of the conductors and the distance between them; and the permittivity of any dielectric material between them. For many dielectric materials, the permittivity, and thus the capacitance, is independent of the potential difference between the conductors and the total charge on them.

The SI unit of capacitance is the farad (symbol: F), named after the English physicist Michael Faraday.[2] A 1 farad capacitor, when charged with 1 coulomb of electrical charge, has a potential difference of 1 volt between its plates.[3] The reciprocal of capacitance is called elastance.

  1. ^ Harrington, Roger F. (2003). Introduction to Electromagnetic Engineering (1st ed.). Dover Publications. p. 43. ISBN 0-486-43241-6.
  2. ^ Cite error: The named reference NSW was invoked but never defined (see the help page).
  3. ^ "Definition of 'farad'". Collins.