I want to use a red and green bi-coloured two legged LED, with red for standby and green for on, but am not sure about how to go about it and have found limited information by googling. I understand that one leg acts as the cathode for one colour and vice-versa for the other, but how do I switch between the two?
Greetings & salutations. http://www.maplin.co.uk/Module.aspx?ModuleNo=35740 I've never seen a 2 legged bi-coloured led (cant say I've looked much though), but if you have the otion for a 3 legged one- well, the diagram in the link above is pretty self-explanatory. I'd guess thats how a 2 legged one wouod work too- swap the polarities around and you get a different color: hopefully thats some use to you
They work exactly as the schematic suggests, it's just two LEDs in antiparallel but in one package, to light it one colour you pass current through it one was, to get the other colour you pass the current the other way. Moriquendi
Adding to that, if you alternate the current quickly enough, a red/green led will appear yellow to the human eye.
I am going to make a tic tak toe using bicolor led. is it possible to make the bicolor led glow differently according to my wish and that's also using only one switch? please help me...
Interesting - I am considering changing the bi-colour LEDs on my V60 keyboard, but I'm not sure which type of bi-colour they are. Out comes the multimeter...
It's simple: two legs and it's a bipolar LED: flick the polarity for the other colour. Three legs and it is bi-colour with an anode (positive) for each colour and a shared cathode (negative). Although you can also find ones with a shared anode and two cathodes. If this concerns a PC, some motherboards have the option for a dual LED header, which allows you to show one colour for standby, one for on. Because of how the motherboard connectors roll, this requires two LEDs to be hooked up or one bi-colour LED of the three-legged kind. If your motherboard does not have such an option, it all gets a bit more tricky. You have to syphon 5V off the USB line to drive a flip-flop circuit connected to the bi-colour LED and the mobo LED header to know its status.
Hello, Just found a tiny toy keyring. When i took it apart, there is an LED in front, connected to three button batteries through a primitive switch. When it is ON the led flashes red and blue, alternating about every half a second. The led looks completely like normal led. Two legs. Nothing unusual inside the led. Any idea how it is done? What this led type is called? Thank you. Arnon
That would be a bi-colour flashing LED. They work by having a tiny integrated circuit inside that flashes the LED (you can get ones that do more complicated patterns too).
