Hi All,

I'm sorry to be that guy (or that thousandth guy) to ask a resistor question when there are entire sticky threads devoted to the subject, but I've read all of them and I'm still having some trouble and figured there was no better place to turn.

So I'm building a custom Yoda for my son with an NBv3 sound board, Green/Green/White CREE XP-E2 Copper Nova LED, a 3.7volt 18650 Li-Ion battery, and a 12mm antivandal momentary switch with green illumination. Here is where my issue begins with the resistor math:


For the main Tri-CREE Green LEDs
3.58v @ 1000ma
=(3.7v-3.58v)/1a = 0.12ohms
Power = 0.12ohm * 1^2 = 0.12watts

I think that's all well and good but when I check myself against the online calculators it doesn't even seem close, and friends of mine that have built Graflexes say the standard for a green led is a 1ohm2watt resistor, but I just can't make that math work.

Online calculators:
http://www.led.linear1.org/1led.wiz
This one says 1ohm 2 watt

http://www.ohmslawcalculator.com/led...tor-calculator
This one says 0.12ohm 3.58watt


Similar issue for the Illuminated switch though I certainly come closer to the online calculators:
3.0v @ 20ma
=(3.7 - 3.0)/.020 = 35ohms
Power = 35 * .020^2 = 0.014

Online Calculators
http://www.ohmslawcalculator.com/led...tor-calculator
This one says 35ohms 0.06watt

http://www.led.linear1.org/1led.wiz
This one say 39ohms 0.125watt

Any help or guidance here would be greatly appreciated!

- Red Hawk