electric potential

Electric potential is the work done against an electric field in bringing a unit charge to a given point from some arbitrary reference point (usually earthed), measured in volts (i.e., joules per coulomb). Charges will tend to flow from points at one potential to those at a lower potential, and potential difference, or voltage, thus plays the role of a driving force for electric current. In inductive circuits, the work done in bringing up the charge depends on the route taken, and potential ceases to be a useful concept.