CCG.
Cacole hit it right with the 1K 1/4 watt resistor. The 5 volt LED will light just as bright as the 2.5 volt.
A friend of mine lit his buildings with golden white LEDs mounted in the floor and shined up to a ceiling that had the shiny side of aluminum foil with crinkles in it to diffuse the light. With shades and other window treatment it looks great. In one small garage he put one of them ark welder LED system and lined the walls and ceiling with smooth shiny tin foil. That looks awesome when its working. In an industry building he made outside wall mounted lights similar to modern wallpacks. The outer lens is clear styrene that is fogged by MEK with bright white LEDs behind the lens. Those look great.
Pete
I pray every day I break even, Cause I can really use the money!
I started with nothing and still have most of it left!
As a general rule, a 1K Ohm 1/4 Watt resistor should be adequate for LEDs, but I think you're going to find that they are not very good for interior building lighting except the Inverted Cone type due to their narrowly focused beam. The inverted cone types emit light in a 360 degree arc instead of only 15 degrees or so.
I have been in model railroading for less than a year. I am ready to start using LEDs on my HO layout. I am operating all of my general area lighting at 12 vdc and the interior lighting at 6 vdc, using 14 volt bulbs. I keep the interior lighting at a lower voltage, as reccomended in this forum, for a better looking light. I am finding that the LEDs operate at from 2.1 vdc up to 5vdc, depending on the color. I want to operate the LED lights on the 12 vdc system. My question is, do I have to match the resistor to the LED voltage, or can I use one value resistor for the different LED voltages.
Corbyn City George (CCG)