Technician 2022-2026T0A04
What is the purpose of a fuse in an electrical circuit?
B
Answer
Electrical, RF, and mechanical safety
Type
A
To prevent power supply ripple from damaging a component
B
To remove power in case of overload
C
To limit current to prevent shocks
D
All these choices are correct
Answer Notes
A fuse is a sacrificial safety device designed to protect electrical circuits, wiring, and equipment from fire and severe damage. It contains a thin piece of wire that is intentionally designed to melt and physically break the circuit—removing power entirely—if the current flowing through it exceeds the fuse's safe rated limit.
It is important to understand what a fuse does not do. A standard equipment fuse does not limit current quickly or sensitively enough to prevent deadly electric shocks to humans; that specific job belongs to a Ground Fault Circuit Interrupter (GFCI). Furthermore, a fuse has no effect on power supply ripple, which is instead filtered out by capacitors.
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In the United States, what circuit does black wire insulation indicate in a three-wire 120 V cable?
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Why should a 5-ampere fuse never be replaced with a 20-ampere fuse?