I have an exsisting circuit which, using a relay, switches between two channels. I want to add two RGB LED's to the circuit so that when the relay is off one LED is white and the other is blue. When the relay switches on I want the colors to switch on the LEDs.
My qustion is can i use the exsisting 8v supply on the relays to power and switch the LEDs? And do i need to use some type of MOSFET or JFET to switch between the different colors? I'm trying to save cost by not using another relay in the system.
I know I'm going to have to figure out the correct values to turn on the different wavelengths.

Any ideas on how to go about this?

Thanks

 

I have an exsisting circuit which, using a relay, switches between two channels. I want to add two RGB LED's to the circuit so that when the relay is off one LED is white and the other is blue. When the relay switches on I want the colors to switch on the LEDs.
My qustion is can i use the exsisting 8v supply on the relays to power and switch the LEDs? And do i need to use some type of MOSFET or JFET to switch between the different colors? I'm trying to save cost by not using another relay in the system.
I know I'm going to have to figure out the correct values to turn on the different wavelengths.

Any ideas on how to go about this?

Thanks

If you use a single pole double throw relay You could switch between the two leds without any thing else.
The tricky part is the wiring of the relay. What you want to do is to apply power to the center pole. This way when the relay is on one light will light and the other will light when it is off. Now if you want this to go back and forth than you will need a circuit to control power to the relay. There are several options of doing this. A MOSFET or JFET is a little much here but could work.. A simple timer or a couple of transistors will do the trick as well