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Bi-color LED's Answered

Hey. I was looking for some small, or even surface mount, bi-color LEDs. I also, however, need a wide range of colors, as I am doing a Rubik's cube type thing. I was contemplating the idea of Tri-color LEDs, and having the 6 colors be RGBCMY, although that may over-complicate things. Thanks for your help :-)



11 years ago

There are two types of bi-color LED. In one type, two LED "chips" are connected in inverse-parallel (bipolar LEDS),; put + on one side and - on the other, and one of the chips will light. Connect them the other way, and the other chip will light. Read/green is common, and you can get intermediate colors by switching the voltage direction rapidly. The other type has two LED chips with a common cathod or common anode (and thus three leads rather than two); you can have both chips on simultaneously for an intermediate color, which is slightly simpler than the bipolar LEDs. In either case, it takes essentially two microcontroller pins to control the color. (There are combinations other than red/green (apparently red is a no-no in many applications because of some international standard or other.) Usually these are yellow/green or something similar; not so useful for intermediate colors. Three-chip "RGB" leds will have a common cathod or annode and four leads, unless they're the kinds with their own controller chip that change colors on their own (not useful if you want to control the colors yourself.) These are still rather expensive :-( I think if you want 6 distinct colors, you're going to beed RGB LEDs (or three sepate color LEDs.)

I was looking for the first type, in 3 pairs of 6 colors. However, if I couldn't find that, I was thinking about getting the second type of RGB.

there are bi colered leds!!