PhysicsChapter 8: Electric Circuits
Fuse
Introduction
A fuse is an electrical safety device designed to interrupt a circuit when current exceeds a safe value. It contains a fuse element that heats when current passes through it. Because heating depends strongly on current: P = I²R an excessive current produces rapid heating. The fuse element then melts, opening the circuit.
Definition
Fuse Rating
A fuse is selected with a current rating suitable for the appliance or circuit. During normal operation it should carry the required current. If a dangerous overcurrent occurs, it should disconnect the circuit.
Why Fuses Matter
Excessive current can: * overheat wires; damage equipment; increase fire risk.
Fuse vs Circuit Breaker
A fuse melts and normally needs replacement after operation. A circuit breaker can generally be reset after the fault has been corrected.
Exam preparation
Exam Focus
Quick revision
Revision Zone
Review the key facts, formulas and checks before you move on.Fuse
Sticky Notes · Quick Revision
FUSE
- High I → Heat ↑
- Element melts
- Circuit opens
60-second revision
- Fuse → excessive current.
- Heating → element melts.
- Circuit → opens.
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