I have a DCC (digital command control) model train layout. On is a reverse loop. This means that the train enters a loop and the tracks end up connecting to themselves again. DCC trains use AC 19V. There are always 19v on the tracks and a special decoder is installed inside the train. By means of a controller, signals is send through the track to the train telling it at what speed to move, the direction, etc.
I have attached a picture of what I want to do. The train is coming from C and proceed through A around the loop to exit it again at B. As there are always 19V on the tracks, you have to isolate the inside of the loop from the main line. Now I use a DPDT ( Double pole double throw) switch to supply current to the inside. I don't know if I can speak about negative and positive with AC, but as you can see the current going in has to be the same as inside. DCC trains are not dependant on polarity. The decoder keep it in the right direction.
So before the train exit at B, I throw the DPDT switch to the other side thus changing the polarity so that it match the outside again. If you do not do this, it will short circuit.
Now all of the above is working fine. What I want to do, is to install a bi-color LED Light ( Red/Green) at point A an B. So when the train enters A, the LED should be Green and the one at B should be Red. As soo as I throw the DPDT switch over, the two lights must change from red to green alternatively. Because of this circiut been AC, if you connect the LEDs, both red and green are on. On a DC system it worked fine.
How do I connect this two LEDs to work like I have explained.
Thanks for listening to my story and for the help
I have attached a picture of what I want to do. The train is coming from C and proceed through A around the loop to exit it again at B. As there are always 19V on the tracks, you have to isolate the inside of the loop from the main line. Now I use a DPDT ( Double pole double throw) switch to supply current to the inside. I don't know if I can speak about negative and positive with AC, but as you can see the current going in has to be the same as inside. DCC trains are not dependant on polarity. The decoder keep it in the right direction.
So before the train exit at B, I throw the DPDT switch to the other side thus changing the polarity so that it match the outside again. If you do not do this, it will short circuit.
Now all of the above is working fine. What I want to do, is to install a bi-color LED Light ( Red/Green) at point A an B. So when the train enters A, the LED should be Green and the one at B should be Red. As soo as I throw the DPDT switch over, the two lights must change from red to green alternatively. Because of this circiut been AC, if you connect the LEDs, both red and green are on. On a DC system it worked fine.
How do I connect this two LEDs to work like I have explained.
Thanks for listening to my story and for the help
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