# pot wattage

#### jack mcleod

Joined Sep 4, 2007
21
How does one determine the wattage for unknown pots?

#### leftyretro

Joined Nov 25, 2008
394
How does one determine the wattage for unknown pots?
If the pot is unmarked as far as manufacture model number then one can only make an educated guess. One could reseach other similar sized pots and get an idea or range of power ratings for that size. Old larger pots used to be pretty standard in 2 watt ratings, but todays various smaller sizes are problably lower in power ratings.

A simple method would be to apply a adjustable voltage across the fixed terminals and see how hot you can get it to become before it burns open. You could then calculate how much wattage was too much.

Lefty

#### Darren Holdstock

Joined Feb 10, 2009
262
Monitor the temperature rise of the track for a known electrical power input. This is not worth doing unless it's a very special pot - much cheaper just to buy a new one.

Something to note is that a pots power rating is for the entire length of the track. If the power is being dissipated only over part of the track, then the input power needs to be derated accordingly.

#### leftyretro

Joined Nov 25, 2008
394
Monitor the temperature rise of the track for a known electrical power input. This is not worth doing unless it's a very special pot - much cheaper just to buy a new one.

Something to note is that a pots power rating is for the entire length of the track. If the power is being dissipated only over part of the track, then the input power needs to be derated accordingly.
That depends on how the pot is being used. If used as a two terminal rheostat then that might apply, however if it's used as a 3 terminal potentiometer then it depends of the impedance of the circuit wired to the adjustable terminal if the position might effect the current/wattage rating.

Lefty