While building the 3-Light Signal Drivers on printed circuit boards (PCBs) I bought from Rob Paisley, it occurred to me that the resistors in the original circuit (which I had been using in my breadboard test circuits) aren’t necessarily of the rating that I’ll need for the signals that I’ll build. They were fine for the testing I was doing with some generic LEDs on a breadboard, but I think the LEDs on my signals will need to be a little less bright than that in order to look realistic. The circuit has separate resistors for each of the three LEDs in the signal (red, yellow and green), so I just assembled all parts of the circuits except for those three resistors. Once I know which LEDs I’ll use in the signals, I’ll be able to determine the appropriate resistors to use. This has prompted me to start some more serious planning for building signals.
While I had free trial access to the Model Railroader Digital Archive last year, I downloaded a PDF of an article they published in July 2006 about building your own signals from commercially available parts. I’m going to base my signals off of that plan, …