How many pn junction a tri colour LED has? I think its three, am i right ?

 

You are correct. Typically a tri-color LED houses three LEDs under one lens, and ties the cathodes together on a common lead.

 

I always thought tri color as in Red and Green, which could produce Yellow (tricolor = 3 colors). You're discribing a RGB diode.

TriColor as I'm thinking of it is two leads, two LEDs, reverse the polaritry with AC to get yellow.

 

Hello,

There are also leds with red and blue in one, the third color look purple/pink (depending how bright blue is) like.

Greetings,
Bertus

 

RGB LEDs are available in common cathode and common anode configurations.

They both have three PN junctions.

There are also red/green LEDs that have but two PN junctions. A yellowish-brown color can be displayed by lighting up both the red and green.

There are also many other color combinations available nowadays.

 

The newest ones that rad shaft has are red, green and blue in one unit. Just got one a few weeks ago.(its a cc unit) Interesting thing to play with. I`ll find a use for it someday!? Robbie in wyoming

 

My solar garden lights have an RGB LED with 2 wires and 3 LEDs inside that slowly fade the colours.