# can i use dpst or spst to power on off tracks?



## idivein (Mar 13, 2013)

service tracks off turntable need to on, off power. can i use spst? they are cheaper and round easier to mount. i want illuminated led. can they be rated 120v? will the lite work at 12v dc?


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## wa2ise (Dec 1, 2013)

SPST switches will work fine. And LEDs run off low voltages (around 2 to 3 volts, but you must use series resistors) anyway. If you are not using toroids for block detection, you could power the LED off the track you are switching the power on or off. Otherwise, you'd get a false indication of track occupancy because the LED is drawing current instead of an engine.


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## DonR (Oct 18, 2012)

idivein said:


> service tracks off turntable need to on, off power. can i use spst? they are cheaper and round easier to mount. i want illuminated led. can they be rated 120v? will the lite work at 12v dc?


A 470 ohm 1/4 watt resistor will be just right to light your LED indicators
off of 12 v dc. 

However, you would need a DPST to also switch the LED with
your track power. If you are using DC on your tracks you could
use the track power thru the 470 ohm resistor, but the lights would
go out or dim as you operate your throttle.

You should be able to find round DPST switches at Radio Shack. They
have a fair selection of types. Using one would afford the most simple
wiring.

Don


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## wa2ise (Dec 1, 2013)

Is your layout using DCC? If yes, you could still use SPST switches, and power the LED off the track (if you are not using toroid block detection). If you're not using DCC but the old fashioned DC, you'd need to use DPST switches, one leg for the track, and the other leg for the LED power.


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