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How to light the LED in a panel switch controlling power to a DCC block of track?

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  • Member since
    November 2020
  • 15 posts
How to light the LED in a panel switch controlling power to a DCC block of track?
Posted by Mark Walther on Wednesday, January 20, 2021 11:14 AM

I was hoping to have a control panel switch with a LED on it control each of my hidden staging yard tracks and light when the switch is on and DCC power flowing to the block as I think it wise to cut power to track with locos not being used at the moment. 

From what I am reading, this in not a simple matter of adding the switch to the circuit.  Can it be done simply?  Does the switch used need to be double pole or can it be single pole?  All of the ligted switches I am finding are SPST. 

Likewise, one of these staging tracks is to serve as my programming track.  I understand that that will require a DPDT switch - still looking for a lighted one to match the others.  Thank you in advance!

  • Member since
    January 2009
  • 5,890 posts
Posted by RR_Mel on Wednesday, January 20, 2021 12:52 PM

If all you are only wanting to do is turn the power off to a DCC block you only need to disconnect one rail.  A 12 volt SPST LED switch would work but you would need to put a resistor in series with the ground terminal to keep the LED current under 20ma, wouldn’t hurt to put a diode in series with the resistor to prevent the DCC from damaging the LED.

Most LED SPST switches are 12 volt and DCC voltage is higher than 12 volts.

 

Mel



 
My Model Railroad   
http://melvineperry.blogspot.com/
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.

  • Member since
    February 2002
  • From: Reading, PA
  • 29,842 posts
Posted by rrinker on Wednesday, January 20, 2021 4:24 PM

 You really only need the switch to be single pole. Just gap the same rail on each siding - don't gap the left rail on one staging track and run the feed through the toggle, then gap the right rail of the second staging track. Pick a side and be consistent.

 The one that will be the program track needs both rails gapped. You can have an LED that is on when DCC power is turned on, but the LED would eb off when the track is switched off, or when in program mode. If you want a different LED to light when in program mode, you'll need more switch contacts, since the program track does not have constant voltage to it.

 In fact, the best way to do a program track is to have an in-between isoalted section that goes completely dead when in program mode. This keeps a loco from creeping over the gap during programming an dlinking the whole layout to the program track - either programming every loco on the layout, or frying the command station.  For that you need a 4PDT switch, and that's before controlling any LEDs.

 Diagrams for the program track here on DCC Wiki:

DCC Programming track (dccwiki.com)

                                           --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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