Light emitting Diodes

[GN.2-6-8-0]

Having converted a brass GN.2-10-2 over to DCC and not having a clue as to what would best would work for a headlight, some have suggested LEDs, wish to know What are the best size/voltage LEDs for headlights and also what resistors would be needed if any.

 

[NZRMac]

I've used these 3mm ones in a couple of projects, they come with a pack of resistors and are ready for a decoder (12v output) http://www.tonystrains.com/products/mini_leds-yeloglo.htm

Ken.

 

[kjd]

I wrote a description about how I installed a LED headlight in my brass NP A-5:
http://www.modelrailroadforums.com/forum/showthread.php?t=5932

You need to add a resistor. To figure the value, measure the voltage output of the light leads, typically around 13V. Subtract the voltage needed by the LED, typically 3.3V. Divide the difference by the current of the LED, usually 20mA or .02A. In this case you need 485ohm resistor. Between 500 and 1k will work. Some decoders, none I have used, have built in dropping resistors then you don't need it. I hope that helps. Ohms Law V=I*R
http://www.grc.nasa.gov/WWW/K-12/Sample_Projects/Ohms_Law/ohmslaw.html