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Potentiometer power rating ?

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tron87

New Member
Can someone please explain to me what the difference between the Linear and log power ratings of a potentiometer mean ?
 

PatM

Member
Linear or Log refer to the tapir of the control (how the resistance varies with operation) not power rating.
 

JimB

Super Moderator
Most Helpful Member
Linear and Log has nothing to do with the power rating of a potentiometer.

Linear and logarithmic relates to the variation of resistance as the potentiometer shaft is rotated.

JimB
 

tron87

New Member
Thx tht cleared that up.


When a linear pot is being used as a variable voltage divider what does the power rating of that pot refer to which bit wiper?
 

audioguru

Well-Known Member
Most Helpful Member
A potentiometer has its power (heating) rated when it is turned to maximum so that its entire resistance track dissipates the heat. When the pot is turned down then only a small part of its track dissipates the heat and then it might burn out.
 

Sceadwian

Banned
The rest of the track will act as a heat pipe so the power drop as it approaches it's lowest resistance vs it's highest will not be linear. This can often be avoided by putting an additional resistor inline with the POT so that the minimum resistance is limited and the additional power resistor dissipates most of the heat rather than the POT itself at low values.

In order to do this you need to know the entire resistance range and voltages that the pot will encounter and define your range to value the power resistor.
 
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