Measuring current and voltage

Current is measured using an ammeter.

To measure the current flowing through a component in a circuit, an ammeter is always connected in series with the component.

Key points

When measuring current:

  • current is measured in amperes, A;
  • the current flowing through a component in a circuit is measured using an ammeter;
  • the ammeter must be connected in series with the component.
Circuit with a cell, switch, lamp and ammeter connected in series.

There is a voltage (or potential difference) across an electrical component when an electric current flows through it.

Key point

Measuring potential difference (voltage)

  • voltage is measured in volts, V;
  • the voltage across a component in a circuit is measured using a voltmeter;
  • the voltmeter must be connected in parallel with the component.
Circuit with a cell, switch and lamp. A voltmeter is connected in parallel with the lamp.
Move on to Test
next