If you think of a circuit as a tube and the electrons as marbles... the amperage is how many marbles pass a given point in a given amount of time... the voltage is how steeply tilted the tube is... 250 volts would be a tube that is at a 80˚ angle from horizontal and the marbles move pretty quickly... 12 VDC would be the same tube at a 20˚ angle from horizontal... the marbles still move, but not as quickly...
If you cut a section out of the tube... that would be a blown fuse. The higher the voltage, the more likely the marbles are to jump the gap. At 20˚ from horizontal a small gap would probably drop any marbles trying to cross. At 80˚ the gap probably has to be a bit larger for the marbles not to jump it.
Thanks, I had physics in college all the way up to wave and magnetism (and then some electronics, VLSI and other crap
). I have a general idea, though it's been a very long time
What I don't get is - the power passing over any given circuit is I*V. So, the same amps (I) and higher voltage (V) would cause more energy to be passing through the fuse and, subsequently, should create more loss in the same resistance, more heat and have it melting faster. Yet apparently it does not matter.
Oh well, may be I should go ask for tuition money back