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
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!
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