The original definitions of electrical units (including those of power and energy) given in terms of experimentally determined quantities. They were originally designated practical units, and later international units, and the unit symbols given by the subscript “int. ” The relationships between the international and absolute units of electromotive force (the volt) and resistance (the ohm) were formally defined at the CIPM of 1946, and the relationships between other international and absolute units may be calculated from them.