Loading…
Loading…
GCSE Physics · key term
A safety device containing a thin wire that melts and breaks the circuit when the current becomes too large.
Used by AQA and Edexcel
Specification 4.2.1.1 · Paper 1
A safety component that melts and breaks a circuit if the current is too large.
Revise: Standard circuit diagram symbolsStandard circuit symbols: Cell; Battery; Open switch; Lamp; Fuse; Ammeter; Voltmeter; Resistor; Variable resistor; Thermistor; LDR; Diode; LED. Resistors and related components use the European rectangular style.
Specification 10.38, 10.39, 10.41 · Paper 2
Trace the fault sequence in order: live wire touches the metal case → a large current flows through the earth wire → the fuse melts or the circuit breaker trips → the supply is disconnected.
Distinguish the devices clearly: a fuse must be replaced after its wire melts, whereas a circuit breaker opens a switch and can be reset.
When explaining the position of a switch or fuse, state what happens if it is placed in the neutral wire: current may stop, but the appliance remains connected to the live supply.
Create a free account to read GCSE Physics revision notes for your exam board and track your progress.
A safety device containing a thin wire that melts and breaks the circuit if the current becomes dangerously large.
The earth wire provides the route; a fuse or circuit breaker disconnects the circuit.
A safety device containing a thin wire that heats and melts when the current is too large, thereby breaking the circuit.