# LEDs and incandescent



## GrapevineFlyer (Sep 7, 2015)

I am converting some locos to DCC-ready. Some of my locos have low voltage LED lighting in them and some have higher voltage incandescent bulbs. How is this handled in DCC decoders? Are most decoders (like the Tsunami and Tsunami2) set up for one or the other? or can they handle both voltages? Do most decoders offer full voltage and its up to you to add resistors? Thanks


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## Brakeman Jake (Mar 8, 2009)

There's no single answer to your question.Some installs need resistors,others don't.You'll have to read the specific instructions that come with your components.


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## Bwells (Mar 30, 2014)

When you say converting to DCC ready, do you mean you are adding the 8-9 pin connector or are you adding the decoder as well?


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## gregc (Apr 25, 2015)

GrapevineFlyer said:


> Some of my locos have low voltage LED lighting in them and some have higher voltage incandescent bulbs. ... Do most decoders offer full voltage and its up to you to add resistors?


incandescent bulbs of a specific voltage are usually selected because of the available voltage. For model railroads, this might be 12V.

LEDs operate as a much lower voltage, but more importantly, need to be current limited with a resistor. A resistor is chosen both to drop the voltage across the LED and limit its current. See LED Circuit As long as the available voltage is greater than the operating voltage of the LED, an LED can be used with a suitable resistor.


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## DonR (Oct 18, 2012)

Most DCC decoders output 12 V DC to the head and
reverse lights. There is no choice.

If your loco has incandescent you would simply connect
the lights per your decoder manual.

If your loco has LED lights most likely they are
already equipped with the correct reduction resistor.
If so, you would again connect per your decoder manual.
However, you should also check the existing light
wiring for DIODES. If they are there you will have
to cut them out before connecting to the decoder.

Don


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## Cycleops (Dec 6, 2014)

Some decoders have resistors built in, some don't so you need to check, mostly they don't. The advantage of LEDs is they last much longer than bulbs.


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## mopac (Feb 24, 2011)

Use a volt meter and see what the light leads from the decoder are reading. If it is 12 volt you will need resistors for LEDs.


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