dual color leds

[mollick2]

I'm curious as to how dual color leds work, what exactly is the deciding factor of what color it is at any givin moment and how you would control the color.

is it decided by the forward flow of mA or what?

I ask this because i'm trying to figure out how exactly i could hook them up to switches on my fanbus i am building.

Which brings me to another question, could i control the fans with a double pol switch and have a 12v and 5v line to run the fans(all rated 12v) have the 5v as a low power for idle times and 12v for when it was being used? or would this not work?

[Spawn-Inc]

first off welcome to the forums!

as far as the led are concerned there only 1 colour, i'm not sure how they get there colour but no matter the voltage (within certin limits) and there is only 1 way for the current to flow otherwise it won't work. bi or ever tri coloured led's basically have 2 or 3 led's in one head.

http://www.dansdata.com/images/caselight/led322.jpg

theres the anode and cathode. here is a really good picture to show you.

with bi or tri leds theres more anode. you can see the two anode's in the picture below.

http://img.alibaba.com/photo/5119527...r_LED_Lamp.jpg

its hard to see but there are 3 anodes in this one.

http://www.ledshoppe.com/Photo/Produ...o/PICT0637.JPG

here is how you would hook it up, red is positive, and black is negative.

I'm curious as to how dual color leds work, what exactly is the deciding factor of what color it is at any givin moment and how you would control the color.

so to answer your question it's basically 2 or 3 led mashed into one.

as for the second part i'm pretty sure you can. i made this picture as to go about hooking it up. so find a crappy/older fan that still works and test it out. i'm 90% sure it will work. the reason i'm not too sure is because i'm not clear if by double poll switch you mean a switch with on | off |on switch. if thats the case it would work.
the black wires are negative/ground, red is 12volts and positive, and yellow is 5volts positive.

[.Maleficus.]

*Paint made LED + Battery pic*

Did you intentionally make that look like a penis?

[Spawn-Inc]

HAHA, oh man i didn't even see that and i can turn anything sick.

[xRyokenx]

Did you intentionally make that look like a penis?

Of course that's what's noticed first, lol.

[.Maleficus.]

HAHA, oh man i didn't even see that and i can turn anything sick.

So it wasn't intentional? It didn't look a little weird when you made it? lol I'm just kidding man.

Of course that's what's noticed first, lol.

You know you saw it too...

[Jim Beam]

I never thought of hooking the LED's up to my balls either

[mollick2]

thanks for your help, i was planning on using the dual color led's as a indicator so for the fan being on low or high, but i don't think it would be too simple.

[.Maleficus.]

thanks for your help, i was planning on using the dual color led's as a indicator so for the fan being on low or high, but i don't think it would be too simple.

I think you're probably right. While it might be possible, I think the color of the LED is pretty cut-and-dry, ie. it would be either red or blue, no in between so all it would really do is indicate -50% or +50%. You might be able to do it with a toggle switch, and have one side be connected to 5v and run the fan off that (low speed) and then the other side be 12v (high speed) and have the LED switch on either side, but then you would only get 2 speeds, and I'm not even sure how easy that would be.

[Spawn-Inc]

thanks for your help, i was planning on using the dual color led's as a indicator so for the fan being on low or high, but i don't think it would be too simple.

it wouldn't work on the same switch with the fan. you would need two switchs, one for the led and the other for the fan. i just tried making a paint picture of it and i couldn't make it work with out lighting up both leds (both poles on a bi colour) at the same time.