# Potential difference

The flowing through a component depends on:

• the of the
• the across the component
Potential difference is a measure of the amount of energy transferred between two points in a circuit.

### Measuring potential difference

Potential difference is also known as and is measured in volts (V). The potential difference across a component is measured using a placed with the component.

## Energy, potential difference and charge

When a charge moves through a potential difference, is done by the power supply and energy is transferred from it to the component and/or its surroundings. The potential difference can be calculated using the equation:

This is when:

• potential difference is measured in volts (V)
• work done is measured in joules (J)
• charge is measured in coulombs (C)
One volt is the potential difference when one coulomb of charge transfers one joule of energy.

### Example

2 C of charge transfers 4 J of energy. Calculate the potential difference needed.

Question

3 C of charge moves through a potential difference of 6 V. Calculate the energy transferred.

Rearrange the equation: