After connecting a SPST toggle switch in series with the DCC track power, so I can turn off power to a yard area, I would like to add a "pilot light" LED (with appropriate resistor?). Thought about it for awhile and now realize that doing it correctly, without dropping the DCC alternating current voltage too much, might not be simple. Would you kind guys have a fairly simple circuit diagram for the purpose, which you have actually tried? I know there are lighted toggle switches available, but suspect they might involve some tricky circuitry, too. In recent years I have experimented with some simple electronic projects and fried a few components due to ignorance, but soldering skills are not my problem. Thanks for any help! Bob of the BB&W
bobbauie@tds.net <snip> I know there are lighted toggle switches available, but suspect they might involve some tricky circuitry, too. <snip>
<snip> I know there are lighted toggle switches available, but suspect they might involve some tricky circuitry, too. <snip>
Bob,
The SPST lighted toggle switches I found in a quick Google search are no more complicated to wire than a standard non-lit toggle switch -- http://www.action-electronics.com/switches.htm#Lightedpad and http://www.action-electronics.com/pdf/gcsw16.pdf (I am sure there are other sources out there with similar, perhaps cheaper, options.)
There are only the two terminals to which you attach your wires. The circuitry to incorporate a light is built into the switch so you have nothing to worry about.
bobbauie@tds.net After connecting a SPST toggle switch in series with the DCC track power, so I can turn off power to a yard area, I would like to add a "pilot light" LED (with appropriate resistor?). Thought about it for awhile and now realize that doing it correctly, without dropping the DCC alternating current voltage too much, might not be simple. Would you kind guys have a fairly simple circuit diagram for the purpose, which you have actually tried? I know there are lighted toggle switches available, but suspect they might involve some tricky circuitry, too. In recent years I have experimented with some simple electronic projects and fried a few components due to ignorance, but soldering skills are not my problem. Thanks for any help! Bob of the BB&W
The LED and resistor go across the track, not in series with the power lead to the track, so there is no voltage drop, and only a tiny bit of current used. Also, use a bicolor LED, not a regualr one. Since the DCC ssignal alternates polarity, a regualr LED by itself will have full votage revered across it half the time. LEDs don't like this long-term. a two lead bi-color LED is actually two LEDs hooked back to back, there are only 2 wires soming out of it, same as a regular LED. Typical colors are red and green, so across the DCC signal they are a reddish-orange. If your DCC system supports running a DC loco on address 00, the bicolor LED will also tell you if this is happening - in one direction it will get more green, in the other, more red. As an alternate you can connect a regular diode in reverse across a regular LED.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Randy..That's nifty, and well within my capabilities. Thanks! Bob
Timothy, I think I'll include a lighted toggle switch in my next order to the popular electronics sources. The way circuits are miniaturized still amazes me after these many years. Thanks for your advice. Bob
You will want a two lead led. Don't get one with three leads.
I use a bicolor led with a 1k resistor to check for power around the club layout. If your system allows for zero stretching, the led can be used as a simple "phase checker".