# Potential difference

The energy transferred per unit of charge as it moves between two points, measured in volts (V). It is what pushes the current round.

Physics (school) · Part 06: Electric circuits · Card 2 of 8 · Last updated 2026-10-19

## Analogy

The push from a pump: a bigger pump pushes water harder.

## Example

**Energy per charge**

V = 6 V, charge = 4 C
energy = V x charge
energy = 6 x 4 = 24 J

## In practice

A 1.5 V cell gives each coulomb of charge 1.5 J of energy. Voltage is measured with a voltmeter placed in parallel.

## Practice

### Flashcards

- **How is a voltmeter connected?** In parallel with the component.

## Questions people ask

### What does a voltmeter measure?

A voltmeter measures the potential difference across a component, which is how much energy each coulomb of charge gives to it. It is connected in parallel with the component, on separate branches that join either side of it, so only a tiny amount of current flows through the meter.

### What is the difference between voltage and current?

Voltage is the push that makes charge move, and current is how much charge actually flows each second. A battery supplies the voltage. The current that results depends on the resistance of the circuit. High voltage with high resistance can still give only a small current.

## Related concepts

- [Electric current](https://studyvisually.com/learn/science/physics-school/physics-school-part-6/physics-school-part-6-concept-1)
- [Resistance](https://studyvisually.com/learn/science/physics-school/physics-school-part-6/physics-school-part-6-concept-3)
- [Ohm's law](https://studyvisually.com/learn/science/physics-school/physics-school-part-6/physics-school-part-6-concept-4)
- [Electrical power](https://studyvisually.com/learn/science/physics-school/physics-school-part-6/physics-school-part-6-concept-7)

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