Tortoise and Bicolor 3 Lead LEDs
#1
I asked this in my layout blog but thought I would post it here as well:

I have a question regarding the Tortoise switch machine and wiring 3 lead BiColor LEDs. Does anyone have a diagram of how to do this? (I do not have 2 lead BiPolar LEDs so I can't just wire them in) My thinking is that I connect the common anode to either pin 1 or 8 and then wire the 2 individual cathodes to pins 2 and 3 (or 6 & 7). and use pin 4 to power the frog of the turnout. Any thoughts?

Thanks,
John
John
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#2
Sometimes it's just easier to punt and get the right LEDs. However, you can use the three lead ones but you will need to power then seperately using one of the contact sets ont he Tortoise. You can't just put them in series witht he power on 1 and 8 like you cna with an ordinary LED or a 2 lead bicolor LED. First, you need to know if the 3 lead ones are common cathod or common anode. That will determine which which side of a DC power supply gets connected to the common lead. The two other leads go to one of the switch contacts on the Tortoise, 2 and 3 or 6 and 7. The common for that switch goes to the other side of the DC power supply. Don't forget an appropriate resistor, it can be on the common of the LED or the common switch terminal of the Tortoise. You can use the same power supply that runs the Tortoises, but you cannot tap off pin 1 or 8 as the polarity there will change as you flip the turnout.
See what I mean, it's FAR easier to just splice a 2-lead LED into the feed to pin 1 or 8, no resistors required.

--Randy
Modeling the Reading Railroad of the 1950's in HO

Visit my web site to see layout progress and other information:
http://www.readingeastpenn.com
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#3
Thanks Randy! Yeah, I know it will be a bit more work but, I got them for free so I can't complain.
Thank you for your explanation, it cleared things up.
John
John
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