Electric Current

What is Electric Current?

Within Physics, which covers forces, energy, waves, electricity, magnetism, light and space explained through motion and experiments, this topic explains Electric Current. Physics topics explain how things move, push, heat up and carry energy, so each one here pairs a definition with a live model you can change.

Check that you can explain Electric Current in your own words and give one example from everyday life. If you can do that, you have understood the core idea.

Understanding Electric Current explains how the physical world behaves, from sport and transport to electricity and medicine.

Electric Current in detail

Electric current is the rate of flow of charge: I = Q/t, measured in amperes (A), where 1 A is 1 coulomb per second. In metal wires, the charge carriers are free electrons, which drift from the negative terminal to the positive, though conventional current is drawn from positive to negative.

Current is measured with an ammeter connected in series. A current flows only in a complete circuit, and in a series circuit the current is the same everywhere, while in parallel circuits it splits at junctions and the total is conserved. Current is what causes heating, lighting and magnetic effects.

How the interactive helps you understand Electric Current

Watch the circuit in the interactive. Use any sliders or buttons it offers to change the values and see how the circuit responds.

Before you change anything, predict the result. Then change one value at a time and check whether your prediction was right. This is a quick way to build a correct mental model of Electric Current.

Real-life uses and examples

• Explain everyday devices, such as brakes, lifts or chargers, using Electric Current.
• Use Electric Current to make sense of a practical and its results.
• Answer “explain” questions by linking Electric Current to a clear cause and effect.

Common mistakes to avoid

• Forgetting that some quantities, such as force or velocity, also have a direction.
• Mixing up Electric Current with a related quantity that has different units.
• Learning the definition without testing it. Use the quiz and the interactive to check that you can apply the idea.