I'm still learning electronics, mostly self taught, and there's one thing that's really nagging me at the moment. I am trying to reason out how to calculate the Power (W) consumed by an LED driven by a Constant Current supply. For example:
An LED with a Vf of 2.2V is driven by a 12V supply with constant current of 100mA (basic LM317 constant current arrangement, if it matters). How many watts is consumed and by which parts? Does the constant current aspect of this really matter over a simple resistor arrangement? How much is consumed by the LED itself and how much is dumped as heat in the constant current supply.
I have my opinions, however, I have the feeling that I'm missing something fundamental here, and I want to be sure I've got this right.
If it matters, this isn't homework. I've been out of school for decades. It's just good old fashioned curiosity.
Thanks.