# farad (F)

Farad (F) is the unit for electrical capacitance. It is defined in the International System of Units( SI) and corresponds to the quotient of coulomb and voltage (C/V). Coulomb, in turn, corresponds to ampere-seconds. It follows that a farad (F) is the quotient of ampere-seconds and volts( As/V).

A capacitance of one farad causes a charging current of 1 A for one second at a charging voltage of 1 V.

The unit farad is named after the British physicist Michael Faraday (1791-1867). Since it is an extremely large unit of capacitance, capacitors with much smaller capacitance values between millifarad (mF, `10^-3`) and picofarad (pF, `10^-12`) are used in most circuits in practice. Only supercapacitors have capacitance values exceeding one farad up to several thousand farads (kF).