RGB Led

[theshoeshineman]

I got my LED-Wiz LED Controller yesterday and connected it up to an RGB LED. It worked but I know I'm using the wrong resistors.

Now the input voltage is: 5v
The LED voltage for Blue/Green is: 3.2v
The LED voltage for Red is: 2v
The current for Red/Green/Blue is: 20ma each

So the resistors I think I need are:

100ohm Brown Black Black Black (for Green & Blue)
158ohm Brown Green Grey Black (for Red)

This is fine for one led however, what I want to do is connect it so that 3 leds are using outputs 1, 2, & 3.

So that if I turn on output 1 all three leds shine red. Then if I turn on output 3 (blue) all three leds will go purple.

My question is would this modify the equasion?

Would I have 3 wires from the red leg of each LED going into output 1 and a 158ohm resistor on EACH wire.

OR

Would I have one 51.1ohm resistor (as 60ma is now being drawn from output one) and then the three wires coming off that resistor going to the red leg of each LED.

Hope you can follow :|

[crazybillybob]

You can do the 3 resistor (one on each leg) or use 1 of the same resistor (158 for red) and tie all the legs to it. Whats the difference?

The power requirement for the resistor. The 3 resistor method the resistors only handle 1/3 the power. That means the single resistor method the resistor is handling 3 time the power.

So what's this mean to you? If your current for each LED is 20mA then the current for 3 is 60mA so P=IE or W=.06x5 W=.3 So you'll need a half watt 158ohm resistor (your going to end up with a 160 ohm or a 150 ohm, as 158ohm is a non standard size).

Hope this clears things up for you...

CrazyBillyBob