I have re-purposed an old 300w power supply from one of my computers. I am going to take advantage of the 12/5/3.3v rails and there's going to be plenty of power to hook up just about anything I am going to need. The question I have is, pertaining to LEDs and the 3.3v rail, will I still need the resistors so it won't blow the LEDs out? If I still need the resistors, do I even bother running the 3.3v rail around the setup and just use the 12v/5v rails? thanks.
you will still need resistors on any of the supply rails .. white leds are only 3 volt [max], and other colours are less
I agree, use the 5 volt with resistors. That way you can easily have different light intensities. On the two throttles I just built the voltage is 3.3v and I'm using 1k resistors and the LEDs are still a little brighter than I like so might still change the resistors. Sumner
Adding to my post above....you could use the 3.3v rail also but since you should still use resistors why run another buss around just for the LEDs when the 5v one can be useful for other items like servos. https://1fatgmc.com/RailRoad/UP%20Canyon%20Division/page-160.html I have the DCC buss and the 5v buss circling the layout with the DCC for the trains and the 5v for the turnout servos and any LEDs or other items that will run off 5 volts. Sumner
Thanks much for the insight. I am trying to think ahead of time what's needed and try not to make more work out of this.
