An open appeal for a simple way to control 2-colour, 2-lead LEDs. I am using these LEDs as the ‘mimic’ lights for my model train layout point control. Working on 12v DC, the point motor is wired to provide a +12v feed to either of 2 connections when the motor switches from one position to the other. I usually use two separate LEDs (1 red and 1 green) wired to a common -12v DC and, I have no problems with the basic circuitry required. However, for these 2-lead LEDs to work, I have to reverse the polarity in order to change the colour output.
I am sure someone out there has a simple solution to this and, I would be glad of any assistance. I can supply any further information you may need.
Let me see if I can understand what you are saying. The points ("turnout" for US readers, I believe) are controlled by a motor, but there is also a switch built into the points, effectively a SPDT switch which supplies 12V to one of two terminals, depending on the state of the points. Normally, two separate leds (with appropriate current limiting resistors) are connected between these two terminals and ground, so that one or the other led is lit depending on the state of the points?
Question: when the points are set to the "left", the left terminal is connected to 12V. But what about the right terminal, is that connected to ground, or is it unconnected?
