Fuse

A part that melts on overcurrent to protect the circuit.

Schematic letter: F
Unit / key rating: Current (A), voltage (V), type (fast F / slow T)

Pinout

2 ends: No polarity.

Real photos

What is it for?

A fuse is a thin wire that melts above a certain current. It breaks the circuit on a short, preventing hot cables and fire.

Fast (F) fuses blow at once on a surge; slow-blow (T) fuses withstand the brief big current at switch-on. Power supplies usually use T types.

Things to watch out for

⚠ Fuses don't blow by themselves: if it's blown, there's a fault behind it. Find the cause before replacing it.
⚠ Never fit a higher-rated fuse or a wire bridge.
⚠ A blackened fuse means a big short; a cleanly broken wire means overload or ageing.

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