In this post I describe a circuit for a Model Railway LED Dimmer. This is used to dim the LED lampposts I am adding to our model railway layout.
The lampposts on our model railway layout are a bit too bright. There are 1K resistors included and these could be swapped for a higher value to reduce the brightness. Instead, I decided to make a circuit to vary the brightness. This allows the adjustment of brightness after the lampposts are installed. This can be fine tuned when the layout is in night mode.
A NPN transistor is used with R1 and RV1 to vary the voltage to the LED’s. The transistor can handle currents up to 800mA so could be used for multiple LED’s. I am dimming 3 lamppost LED’s.
The circuit was assembled on Vero board as it is quick to work with and is stable. The wires from the lampposts will be soldered directly onto the Vero board tracks.
All components can be obtained from Rapid Electronics. The lampposts we are using are these from Layouts4U.