I NEED TO DESIGN A TESTER TO CHECK 2 DIFF. STYLE RELAYS. I HAV DESIGNED ON THAT WORKS WITH ONE L.E.D. TO SHOW IF THE SWITCH CLOSES ON THE RELAY, BUT I WOULD LIKE TO USE A DUAL (REE-GRN.) POLARITY L.E.D.. IF THE SWITCH CLOSES THE GRN. LED LIGHTS, IF IT DOESN'T THE THE RED LED SHOULD LIGHT. I'M NOT SURE HOW TO USE THIS TYPE OF LED. THANKS, ME
Drive current through in one direction to make it light red, drive current through in the other direction to make it light green.
Note that while the red/green difference may be perfectly apparent to you, the most common form of color blindness is red/green, and pure colors like LED's are the most likely to be indistinguishable to someone with the disability. So you're making a tester that will automatically not work for 8 to 12 percent of the male population. Worse, folks with this disability have learned that if you peer carefully at the LED you can tell which chip is on by it's position -- which means they may not say they're color blind, they may just pass a bunch of bad relays for you to use.
Note that to me, the "red green red green" graphic on the right side is _all the same color_.
Throw away those dammed colored lights, an use something that _I_ can use!