Re: a question about power



Gunnar G wrote:
Hi.
I'm a total clueless newbie and I've just bought my first soldering tool and
I'm about to construct a resistor from a small thread with a resistance of
30 Ohm per meter.
The question is: how much power can this thread take? It's going to be a 10
Ohm resistor and the DC current will be like 0.8 A  and it gives a power of
6.4 W.  I don't want things to start burning, is there a risk that 6.4 W
too much power for this small thread?

Probably. It depends on how hot that element can get and still remain a stable resistance, and how easily heat is conducted from it to the environment around it. It takes an object about as large as your little finger to get rid of 6 watts and remain cool enough to not blister you. So it may take two strands in parallel (and twice as long, each) wound around something about that size, and covered in a layer of epoxy, to keep the wire temperature reasonable at that wattage. Bigger is better.
.




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