I've always had a problem understanding resistors. Perhaps I just need to see an example, but until then, I'm completely stuck.
Say I have 3.3v of power with 40mA of current, and I want to power an LED that requires 2v and 20mA to run. What sort of resistor would I use to make sure I don't blow it out?
I know I can calculate the resistance of the two using Ohm's law, but is that what I'm supposed to do? Where do I go from there?