Farad

Farad (from Faraday), the name of the practical unit of electrical capacity, first given by the British Association Committee on Electrical Standards in 1863, and authorised by the International Electrical Congress held in Paris in 1884. Under ELECTRICITY will be found the definitions of the ampère, the volt, and the ohm, which are respectively the practical units of current, potential, and resistance. The Coulomb is the name given to the unit of quantity, and is the quantity of electricity transferred by a current of one ampère in one second; and then the farad is defined as the capacity of a conductor which when raised to a potential of one volt has a charge of one coulomb. The farad is, however, an inconveniently large quantity, so that it is customary to measure capacities in microfarads, the microfarad being the millionth part of a farad. See also MAGNETISM.