Resistor Question

[Yorginsnarff]

I've looked over FJK's "Down and Dirty" Ohm's Law tutorial, and I want confirmation on whether or not these resistors would fry my LED

(I'm using a tri-cree, G/G/W, Greens in parallel).

For the greens: 1 ohm, 1 watt resistor

For the white: 1 ohm, .5 watt resistor

[Forgetful Jedi Knight]

Telling everyone the battery solution would also help them determine whether you are "wrong" or not.

[Yorginsnarff]

yeah a 3.7V lithium ion battery. 1 ohm, 2 watt resistors (for both the green and the single white die) would keep them from frying, right? That's what I got from the "Down and Dirty" thing...

[Forgetful Jedi Knight]

Those aren't the ideal resistors, though they will work.

[Yorginsnarff]

hm... well for example I got 0.12 for the resistance, so should I round that to a .48 ohm 1/2W resistor for the greens and the same for the white?

[Forgetful Jedi Knight]

The White is different, because it has a different Vf from the Greens, but you essentially have it right, now.

[Yorginsnarff]

okay, so I re-did the math.

For greens: (I will be wiring the two in parallel, so I only use one resistor where they splice, right?) I will need one .48 ohm, 1/2W resistor.

For the white: I will need one 1 ohm, 1W resistor.

Correct now?

[Forgetful Jedi Knight]

okay, so I re-did the math.

For greens: (I will be wiring the two in parallel, so I only use one resistor where they splice, right?) I will need one .48 ohm, 1/2W resistor.
Correct now?

You will need 2 resistors. One for each Green LED.

[Yorginsnarff]

oh? In Madcow's video, he twisted the two positives and negatives together and just added one resistor...

so, then I attach one resistor to where the two wires splice, then put the other on the "bridge"of the PeX?

[Forgetful Jedi Knight]

The way Madcow does it is not a way that I recommend. If you are still intent on doing it that way, you would need to double the size of the resistor.