I have recently come back to the world of Model railroading and over the years I have lost any circuit drawings that I had for track power indicators. Can anyone help me, I am using DC power as this will be my learning layout. Thanks in advance. Glenn
Your simplest approach would be to use DPST (double pole single throw (on/off)) switches to control the track power and indicator lights. One pole would feed the track power to the track (on/off) and the other pole would feed to your indicator lamp from it's own power supply (on/off).
Mark.
¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ
I suggest a simple 2 colour (red/green) LED with two leads or two seperate LEDs wired back to front. . Wire a 1K Ohm resister in series and put the whole circuit across the rails, It will tell you when you have power and which polarity it is depending on the color.
Cheers
Alan Jones in Sunny Queensland (Oz)
For DC you might want to use a slightly smaller resistor, with a 1K I'm sort of surprised the LED lights before you get somewhere around half throttle. 560 ohm might be a bit brighter when not running flat out, and still enough to not overcurrent the LED when the throttle is wide open.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I don't understand the logic behind installing the LEDs to the track itself as indicators ?
In order for the indicators to illuminate, you have to open the throttle, which could cause engines to start moving you didn't want because the light was off ! .... kinda defeats the purpose of having an indicator in the first place doesn't it ?
That's why I suggested the DPST switch. The indicator is on constant (when track power is turned on) whether the throttle is on or off.