Multicolor led with 2 pins

Back-to-back leds, with reverse polarity to each other. In your case, one polarity is red, the other blue. If you use AC (with PWM), you can create various other colours.

Quite commonly available. Even from our plain enthusiast stores here in Australia, they're available in both flavours (two and three pin).

This works because leds in reverse polarity behave "sorta like" 5v zener diods. Since forward bias is 2-3v, you'll never come across problems.

To get red blue green you need a RGB diode.

There is a two lead novelty diode with tricolor leds built into a standard 5mm led package.

LED1081 T1-3/4 Flashing RGB LED LED1081 Your Price $1.40

Detailed Description This RGB flashing LED is a winner. Apply 4.5Vdc, 90mA and let the fun begin. The LED flashes red, then green, then blue. If you leave it connected, the LED goes through a multitude of flashing, fading, dual colors, etc. Display your own personal "light show". The flashing rate, at start up, is 1.4 times per second(1.4Hz). Let your mind run wild and figure out new places to mount your new prize. All of this and it is in a T1-3/4(5mm) case. LED1081......

Reverse the polarity.

snipped-for-privacy@gmail.com wrote in news:1191316044.706404.60390 @w3g2000hsg.googlegroups.com:

It uses constant voltage/current to the package for power. There is a chip in the package that does the color cycling and LED driving. There is no way to conrtol what LEDS in the module to light.