I use two Tortoise switch machines to control the access to a hidden staging. I want to install three Leds on a control panel outside of the staging room to indicate which track is active. I use one of the internal switchs of each Tortoise to control which Led will be lit. Here is the wiring diagram.
My question is: As there would be only one Led lit at a given time, can I use only one resistor at A or B or do I have to use three resistors located at C or D?
Guy
Modeling CNR in the 50's
Guy,
On at either A or B will work.
But something to keep in mind based on my experiences stuffing things into loco shells, long term success depends on how the wiring is arranged and what might happen in failure mode. If there's any chance the way the wires run that a short could bypass -- to ground, straight through the circuit, to another circuit, etc, then 3 at C or D provides a bit extra insurance that such a "sneak path" might let the smoke out.
Mike Lehman
Urbana, IL
If your signals are in pears or even in trees, only one resistor is required as only one would be lit at a time. See the LIONS treatse on Tortoises (on the website of him) for more ideas.
ROAR
The Route of the Broadway Lion The Largest Subway Layout in North Dakota.
Here there be cats. LIONS with CAMERAS
Tortoise contacts are SUPPOSED to break before make, meaning only one LED could be on at a time. However, it can happen that duringmovement, both contacts are made. In this case, though, the two LEDs would be in parallel and just be dim because the resistor for a single LED is larger than the one required for two LEDs in parallel. The LEDs won't get excess current if the Tortoise contacts happen to momentarily bridge, so a single resistor for the whole works is fine.
Which end has the resistor does not matter. In the positive feed or in the negative feed, it's all the same.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Thank you all for the replies. The rewiring job is progressing. I will probably be able to post some photos in next WEPF.
Thank you all. Here is the result. The tree yellow LEDS indicate which track of the hidden staging is activated.
Nice Workmanship.