# Questions about voltage and amperage

**URL:** <https://boards.straightdope.com/t/questions-about-voltage-and-amperage/338117>\
**Category:** Factual Questions\
**Created:** [January 2, 2006, 9:29pm UTC](https://boards.straightdope.com/t/questions-about-voltage-and-amperage/338117 "2006-01-02T21:29:18Z")\
**Posts on this page:** 2\
**Page:** 2

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**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\
**Post date:** [January 3, 2006, 6:56pm UTC](https://boards.straightdope.com/t/questions-about-voltage-and-amperage/338117/21 "2006-01-03T18:56:21Z")

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> [@engineer\_comp\_geek](#):
>
> The thing you are missing here is that the amount of energy you are dissipating is dependent on the power. How hot the wire actually gets though depends on a whole bunch of things, only one of which is how much power is going through the wire. Part of it is the surface area of the wire. Another part of it is the temperature of the surrounding materials. You’ve got X amount of wattage generating heat inside the wire, and convection, conduction, and radiation all taking heat out of the wire.

This is what I tried to get at in my 2-liner above. \*\*Snailboy \*\*is assuming that all the heat in the wire must be disipated exactly as it’s being generated. That’s the error. And, heat disipation depends on many factors, not just the surface area of the wire. So all of the heat may be disipated, or the temp may build up in the wire and it’ll literally burn up. Hey, you could use that principle for a fuse technology! 🙂

> [@](#):
>
> Thermodynamics always gave me a good case of the willies. I try and avoid it whenever possible.

Thank God I only had to take one class in that subject. Give me anything, even Quantum Electrodymanics, over Thermo anyday!

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**Author:** ![snailboy](https://avatars.discourse-cdn.com/v4/letter/s/97f17d/32.png) [@snailboy](https://boards.straightdope.com/u/snailboy)\
**Post date:** [January 3, 2006, 11:16pm UTC](https://boards.straightdope.com/t/questions-about-voltage-and-amperage/338117/22 "2006-01-03T23:16:29Z")

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I think you guys have finally got me to understand this stuff. It’s easy to memorize rules, but it can be a challenge figuring out why it behaves like that. I believe knowing what happens without knowing how or why is poor science. I think that’s pretty much everything I’ve wondered about the subject. I better stop asking questions so I’ll have motivation to go back to college. Thanks a lot.

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