What potentiometer should I use for my led strip?
Given that you want to shut current down to maybe 25mA (100:1) reduction you might be looking at a pot resistance of about 250 ohms ohms. Point 1

Point 2 is the power rating - with the pot at a setting that maybe controls half the amperage (1.25 amps) it might be dropping 3 V across it and that means a resistance of 2.4 ohms and a power dissipation of about 3.75 watts.

BUT, BUT, BUT, you can't get a pot that like this - a 10 watt pot is rated over its full end to end resistance - it aint rated at 3.75 watts for the first 2.4 ohms with a gradually smaller power rating as the pot wiper moved to centre then to the far end.

So you are left with a pot that can handle 3.75 watts for each 2.4 ohms of travel. Given that your pot needs to be probably about 250 ohms in total, that's a total power dissipation of 361 watts or something that looks like this: -



Here is the website you can buy it from. Below is one that looks cool but is also big and clunky. It's rated at 500 watts: -



It can be found here and costs £52

I'd stick to using PWM.