ELECTRICAL POTENTIAL

"The electrical potential difference between two point in a circuit is the cause of the flow of a current. It is somewhat analogous to the difference in height in a waterfall that causes the water to fall, or the difference in pressure in a pipeline that causes the gas to flow. In electrochemistry we typically cannot measure ""absolute"" potentials, only the ""difference"" of potential between two points. For similar concepts, see electromotive force (emf) and voltage. These terms are sometimes used interchangeably. However, in electrochemistry ""emf"" usually refers to the potential difference between the two electrodes of an electrochemical cell when there is no current flowing through the cell, ""voltage"" refers to same with current flowing, and ""potential"" is usually used in connection with electrodes (see electrode potential). The measurement unit of the potential is the volt. "