Farad
The title of this article is ambiguous. For other meanings, see Farad (disambiguation).
The farad is the SI unit of electrical capacitance. It was named after Michael Faraday.
A capacitor that stores a charge of one coulomb (C) by charging to a voltage of one volt (V) has a capacitance of one farad (F):
.
(Note: A stands for ampere, s for second, kg for kilogram and m for meter).
The majority of capacitors used in electrical engineering have values considerably smaller than one farad, so that specifications using SI prefixes such as microfarad (µF = 10-6 F), nanofarad (nF = 10-9 F) and picofarad (pF = 10-12 F) are very common.
History
The term farad was introduced by the two English electrical engineers Josiah Latimer Clark and Charles Tilston Bright in honour of the English physicist Michael Faraday and was proposed in 1861 as the unit for electric charge. In 1881, however, the International Electricity Congress established the farad as the unit for electrical capacitance and the coulomb (after the French physicist Charles Augustin de Coulomb) as the unit for electrical charge.
