Voltage

Voltage is the amount of potential energy between two points, where one point has more charged particles than the other. The difference in this charge is called the voltage. We can think of the voltage as the pressure within the circuit to push the charged particles through the circuit. Voltage is measured in volts.

To continue with the water in a pipe analogy, we can think of voltage as the water pressure within the pipe pushing the water through. The following diagram illustrates this: