Quote Originally Posted by FenderBender View Post
You got it!

Except, you need to remember that the second equation for calculating power is from the voltage 'drop'. Meaning that if your LED is 6v (series wired red for example) and your source is 7.4, then your drop is 1.4v x I (current) 1.5 = 2.1 So you'd use a 2W resistor.

For a parallel set up, like for two Green dice, at say 3.8V it would be 7.4-3.8 =3.6 X 1.5 = 5.4 So you'd use a 5W resistor. Or, if you're using the SMD 2512 resistors you can 'stack' them. It's just more math

Thanks guys! This is for you. I will continue to add to it, as I know it's missing some clarification and more/better pics.
Excellent! So power source minus forward voltage. I have been trying to understand that equation for days! This is truly a wonderful day!