What resistor to Use?

[Craw]

I have Two Bachmann 2 truck shay and Two Bachmann Climax I want to hard wire a Tsunami 2 TSU-1100 P.N. 884006 Steam-2 sound decoder with speaker into the Locomotive.

The PCB board that is existing in the locomotive presently will be removed to make room for the decoder and a speaker.

What size resistor do I need to buy to solder to the LED front and back of the Loco?

Thank-you
Craw

[rich1998]

Welcome.


I have used a 1 K, 1/8 watt resistor. That allows about 9 ma through a 20 ma LED which is sufficient.
My Tsunami decoders measured about 12,2 vdc for LED's so I measured about 9 ma through the LED.
Many use that type. Look at the below link that I found some years ago.

http://www.members.optusnet.com.au/nswmn1/Lights_in_DCC.htm

I have started using LED's in 1972 as a NASA rep. Fun things. Different than light bulbs.
Have fun. I have done hard wires before but some years ago.

Rich

[Hunt]

If locos are On30 - use 1k, 1/4 watt resistor with each LED.



an aside --- use speaker compatible with decoder audio amplifier.