Three things are needed for an electric currentElectric current is a flow of electric charges (electrons). to flow in a circuitA collection of wires and electric components connected together in such a way that electric current can flow through them.:
- the circuit must be complete - electric current can't flow if there are any gaps in the circuit
- a batteryA battery is two or more electric cells joined together that can produce an electric current when connected to an electric circuit. or other power source is needed to provide the energy to push the electric current through the wires.
- the battery must be connected correctly. One wire must be connected to the (+) positive terminal of the battery and the other wire must be connected to the negative (-) terminal of the battery.
We use circuit diagrams to represent electrical circuits. This is the circuit diagram for a simple buzzer:
The battery, switch and buzzer are represented by circuit symbols. You can find out more about circuit diagrams in the Power Up Under 11 area.