I’m just getting into electronics and circuits and admit to being clueless in the subject. I have a question about fuses though. Why do fuses have a voltage rating? What is the point?
Forgive me for asking such a simple(?) question. Contrary to what you may be thinking, I have used google to help me find an answer, but everything I found is explained so…um…whats the word…means the same as “over-my-head”… umm…explained with jargon, maybe? Any help is appreciated. Thanks!
erp, geez, I’m such a newb. I think this may be the wrong forum. <begs forgiveness> But this forum is my favorite to lurk in!!!
Fuses are of certain standard sizes and can therefore be placed in circuits of differant voltages since the fuseholders are of the same shape and size.
When a fuse blows it must disconnect the circuit from the supply by creating a break, in sone fuses its just an air gap.
When a circuit is suddenly disconnected many components are still charged up and they will throw a reverse voltage out, especially inductances such as motors, as magnetic fields collapse.
This reverse voltage, called back e.m.f, can be very high indeed and may be capable of jumping the air gap, this may cause additional damage or present a safety hazard.
In low voltage applications such as most electronics this is not much of a problem but when you get to mains supply voltage, and above, it can be and so differant fuses are used.
These fuses will have silicon particles, resembling sand, in the main body of the fuse, which turns to an insulating glass when the fuse melts, and so prevents a backstrike.
When you start getting into grid, 3KV and up, voltages the fuses are long cartridges with multiple elements which together are rated for the current but they are expensive so you would not want to use one of these in a lower voltage application.