DIYbanter - View Single Post - Is the wattage linear on a wirewound adjustible resistor?

Foxs Mercantile

On 2/26/2017 2:42 PM, wrote:
That's kind of what I was thinking, but I had to ask to be sure.

I've never been good at math, but it makes sense that if I'm using 1/3
of the resistor, I am getting 1/3 of the wattage (about 8W).

I don't need to do this, because I have a pair of 8 ohm 100W fixed
resistors, but I was just curious.

This is why the old wire wound rheostats were marked with values
like 0.05 Amps Max. Even though the pot was rated at 50 watts.
(That would be a 20K ohm total resistance for this example.)

Another thing to keep in mind, wire wound resistors have inductance.
Although probably not enough to become a substantial issue at audio
frequencies.

Good ain't cheap and cheap ain't good, but Caddock makes non-
inductive thick film resistors in 20 and 50 watt sizes.

--
Jeff-1.0
wa6fwi
http://www.foxsmercantile.com