A unit of electromotive force, It is the difference of potential required to make a current of one ampere through a resistance of one ohm.

The term most often used (in place of electromotive force, potential, potential difference or voltage drop) to designate electrical pressure that exists between two points and is capable of producing between the two points.

Voltage loss experience by electric circuit due to two principal factors: (1) wire size and (2) length of wire runs.