Easy question / confirmation...

[cjdelphi]

if these ebay pots are 0.1w (see attached)

then...

0.1v x 1amp is 0.1watt ?


So i should be able to use a 10k pot inplace of the resistor to a 1amp load, or have i gone incredibly stupid after writing so much code lol

 

[Harald Kapp]

0.1v x 1amp is 0.1watt ?

Right, but: 1A*10kΩ=10kV, not 0.1V, therefore P=10kV*1A=10kW!
You have several option for calculating the power through a resistor (aka potentiometer in this case):
P=V*I
P=I²*R (becasue V=I*R)
P=V²/R (because I=V/R)
Depending on which variables you know.

For direct control of power by a potentiometer you will need a high power pot (typically wire wound) with only a small resistance.
It is usually more convenient to use the potentiometer to control a suitable power circuit, e.g. a PWM dimmer as in your 2nd attachment.

 

[cjdelphi]

ah, yes of course via pwm to dim it, i'll stick with the resistor

thanks!