- When electric charges move in a wire, we say that an electric current flows in the wire. It's like the way a current of water flows in a river.
- For an electric current to flow, we need two things:
- something to make the electricity flow, such as a battery or power pack
- a complete path for the current to flow in. This is called an electric circuit.
- Voltage is a measure of the difference in electrical energy between two parts of a circuit. The bigger the difference in energy, the bigger the voltage.
- Voltage is measured in volts.
- Voltage is measured using a voltmeter.
- Resistance is measured in ohms. It can be calculated from the potential difference across a component and the current flowing through it. The total resistance of a series circuit is the sum of the resistances of the components in the circuit.
- An electric current flows when electrons move through a conductor. The moving electrons can collide with the atoms of the conductor. This makes it more difficult for the current to flow, and causes resistance.