Capacity Electrical

Capacity, Electrical, of a conductor, is understood to mean the quantity of electricity contained on it when charged to unit potential, i.e. it is the quantity required to produce a charge at the standard intensity of electrical pressure or potential (q.v.). Inasmuch as the electrical pressure depends on the position of the conductor in relation to other bodies, so must the capacity of the body vary as its position varies. The standard capacity is that of a conductor which requires just one coulomb of electricity - the unit quantity, to bring its potential to one volt - the unit potential. This unit capacity is called the farad, but is so great that for practical purposes the unit adopted is its millionth part, the microfarad. The capacity of a mile length of ordinary submarine cable is about one-third of a microfarad.