RGB LED's - a basic question

[thrash-boy]

ok well im looking to modify a dash and replace the globes with color changing led's, and a potentiometer to change each of the colors of the leds (one for red, one from green, one for blue) so i can change the color of the dash lights as i please.

 

 

 

i found a hell of a lot of info at this website: http://led.linear1.org/category/led-basics/

 

but their is still 1 question bugging me,

 

 

 

how exactly do you change the color of a rgb led. do you adjust the voltage or the amps?

 

ive searched for an hour on google, and found plenty of tutorials to make self color changing things (such as things you plug into your computer and program) but i cant find any on how to adjust each color of the led myself.

 

it seems like such a common question, yet i cant find an answer.

 

 

 

can you use a potentiometer or how exactly is it done? what size pot would you use if you can use one?

 

 

 

EDIT: ok it just clicked in my head, there are 2 types of rgb leds.

 

the type that you either have each color on or off (eg red on or red off, green on or green off), in which case you would use the recommended voltage and mA in the datasheet (eg 20mA, 2v or something to have it on, none to have it off).

 

this is all i really was looking for (ill just have a switch for each color), but im still interested.

 

in the other type of led's (the ones that you CAN have different shades of each color, to produce life like colors) how is it done? i would guess with something like PWM (pulse width modulation), but if someone could confirm that it wound be great.

[JoeDaStudd]

I just looked over a few pages and they show that a RGB LED is simply one unit with 3 LED's inside (1 Red, 1 Blue and 1 Green).

 

They use (what looks like) a 3 way variable resister to modify the amounts of each colour, allowing you to change the outputted colour.

 

Nice link with a detailed image on how it works.

[thrash-boy]

I just looked over a few pages and they show that a RGB LED is simply one unit with 3 LED's inside (1 Red, 1 Blue and 1 Green).

 

They use (what looks like) a 3 way variable resister to modify the amounts of each colour, allowing you to change the outputted colour.

 

Nice link with a detailed image on how it works.

 

 

 

thanks for the link.

 

it made me think a bit, and i figured maybe i could use 3 rgb led's for each light, and then i could have 4 stages of each color (off, low, high, full)

 

eg for red:

 

off= have none of the red parts of any led going

 

low = have 1 led part going, and 2 off

 

high = have 2 going, 1 off

 

full = have all 3 red parts going, to produce maximum red light.

 

 

 

that would allow me to have a hell of a lot of different colors, but i don't think ill bother.