[Boatanchors] Boatanchors Digest, Vol 78, Issue 12

[Drew P.]

Bill Stewart wrote:
 
> Is there a rule-of-thumb to indicate the wattage of a
> potentiometer by its physical dimensions?? I'm trying to
> figure the wattage of a 500K audio pot. that's about 1? 1/16
> " dia. by about 1/2 " (pot. only, switch is additional)
> long. 


A pot of these physical dimensions is typically good for 1/2 watt to 1 watt.

A proviso is, however, that a voltage high enough to cause a half a watt or a watt power dissipation will likely exceed the voltage breakdown rating of your 500K pot.

Another proviso to consider for any pot, is that the unit's full power dissipation rating only applies to the full resistance element.  If you were to use the pot so that the power would be dissipated between a wiper at, say, mid rotation and one end of the element, rated dissipation would be less.

In conclusion, it ain't the size that matters, it's how you use it!

Drew