I am planning to use the Atlas HO scale signals for my layout, but I'm not going to use their controller since I have a PLC in place. I have run multiple 12 volt DC drops around the layout for whatever uses I may want, but a lot of it is for the signals. According to the Atlas package the LEDs each use 2.0 to 2.2 volts and 25 to 30 milliamps. I have used a couple of different websites to figure out what size resistor to use and they all say around 400 ohms and 1/2 watt, which sounds really low to me. I really don't want to burn out one of these signals testing unless I have to, so can anyone with some more knowledge (or experience) than I have verify if these resistors sound like the right size? Or is there any other way to get the right resistor the first try?
Good Luck, Morpar
LEDs are much brighter than the used to be and seldom need to be run at full 20 ma current.My go-to resistor is 1K. If that's too dim, I adjust to lesser values by about 100 to 200 ohms at a time. Usually the LED is plenty bright on 1K.
Disclaimer: This post may contain humor, sarcasm, and/or flatulence.
Michael Mornard
Bringing the North Woods to South Dakota!
Different colors may need different resistors to appear the same intensity. Check out this discussion currently in the forum
Henry
COB Potomac & Northern
Shenandoah Valley