Hello everyone! I am new to this forum, and I have a burning question to ask!

I have a model railway, and want to add a simple LED signals system, of a total of 16 green/red signals. I have everything I think I will need, but need help with a circuit diagram of how to put it all together (or better still, a SCHEMATIC diagram!).

I have a 12v dc supply, 16 red and 16 green LEDs (all 3mm, 20mA forward diode current, where Vf typical = 1.9v for the Reds, and Vf typical = 2.1 for the greens).

I also have plenty of simple 3-pole (is pole the correct term for the terminal legs?!) 2-position ON-ON toggle switches.

Obviously for a railway, at any one time, I want EITHER a red OR a green switched on via the toggle switch, per signal.

With that all said, I am lost as I have never done this before! I can solder everything together, but need a clear schemetic DIAGRAM of the whole system.

If anyone could also calculate the exact values of any required resistors, that would be a great bonus

Kind thanks, Kona Kurt.

I have a model railway, and want to add a simple LED signals system, of a total of 16 green/red signals. I have everything I think I will need, but need help with a circuit diagram of how to put it all together (or better still, a SCHEMATIC diagram!).

I have a 12v dc supply, 16 red and 16 green LEDs (all 3mm, 20mA forward diode current, where Vf typical = 1.9v for the Reds, and Vf typical = 2.1 for the greens).

I also have plenty of simple 3-pole (is pole the correct term for the terminal legs?!) 2-position ON-ON toggle switches.

Obviously for a railway, at any one time, I want EITHER a red OR a green switched on via the toggle switch, per signal.

With that all said, I am lost as I have never done this before! I can solder everything together, but need a clear schemetic DIAGRAM of the whole system.

If anyone could also calculate the exact values of any required resistors, that would be a great bonus

Kind thanks, Kona Kurt.

Last edited: