DISCLAIMER: I am just tinkering with electrical engineering and can barely do the basics yet.
I have done a little work on a breadboard connected to my Raspberry Pi, but today I wanted to put my new battery pack to use. I set up a simple circuit to control the brightness of an LED with a potentiometer and it worked just fine. Then in my usual how-much-can-I-change-before-it-breaks fashion, I removed the resistor to see how bright I could make the LED before it burned out (yes I know it was a dumb idea). I got the LED up until it turned red (it was a green led) and then started smelling something burning. The LED was fine but the potentimeter was what was making the smell. Yes, I unhooked everything as soon as I stared smelling burning.
What did I do? I looked online and didn't find anything about burning out a potentimeter.