# What Is Voltage

Energy is required for the movement of charge from one point to another. Let W joules of energy be required to move a positive charge of Q coulombs from a point a to point b in a circuit. We say that a voltage exists between the two points. The voltage V between two points may be defined in terms of energy that would be required if a charge were transferred from one point to the other. Thus, there can be a voltage between two points even if no charge is actually moving from one to the other. the voltage between a and b is given by

**V=W/Q**J/C