Which of the following is the weakest link in an electric circuit?-the switch,the pilot lamp,the fuse or recep
Yes, the fuse, as it is designed to sacrifice itself to save the other parts. However, it is even weaker than you might think if it is a metal-element fuse (vs. a chemical fuse or some other kind). As a fuse operates close to its rating in order that a fairly small increase will blow it, the fuse runs warm, but not up to the melting point. Every time the current is turned on, the element goes from cold to hot, causing the element to physically flex. You can actually see this happening if an open fuse holder is used and the fuse shell is clear glass, of course. And if there is a surge greater than the normal operating current, say due to feeding a cold light bulb, a motor at standstill, etc., the surge will magnify the flexing.
Now what happens if you flex metal repeatedly. Yes, the top of an Aloha Airlines 737 blows off! Or in this case the fuse flexes one too many times, fractures and opens up ("blows" would not be apt) and the circuit fails. Thus any fused circuit operating near the fuse's current rating is waiting for a fall, so keep that in mind.
If fatigue is the cause, that is one case where replacing the fuse without checking the circuit for faults leading to excessive current is OK. After all, the circuit is not bad, just too old. (Hmmm, sounds like me.)
With any luck, the fuse. It's designed to be the weakest link. You want it to be the first device to fail.
The fuse, thats the purpose
By design, the fuse. Its purpose is to fail when the circuit is subjected to too much current, shutting down the circuit and preventing damage to the other components from overheating from the current overload.
It seems like it's always the most expensive component!
Fuse.. As this is its existences.
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