HOME BUILT TRANSISTOR THROTTLE AND POWER SUPPLY
The throttle and power supply is now hard wired in the location (engine service) that I built it for. It has 1 amp of power that is sufficient for moving any one engine at a time. Mainline throttles should have 3 amps of power for powering multiple engines like double or triple headers.

You can bearly see the MRC Tech 2 stationary throttle at lower right that has been around thirty years. It still works fine, I just wanted to go with a hand held unit. The Tech 2 is now used only for powering the turn table as it has a fixed DC output and the AC terminals power the roundhouse and yard lights.

Half the modelers out there still run DC as I do so I’ll tell others how to build it if interested. There is an on/off switch on the upper right because the system is always on at it puts out 2 volts even when the speed control knob is turned off. This allows the engine to move at a slight crack of power. The forward/reverse switch is at the lower front. Forward is in the up position and reverse down.

The filtered DC power supply is at right with the 1.2 amp transformer in the same box. These are from Radio Shack as well as the switches, resistors, diodes, electrolylic capacitor, power transistor and transformer. The wire wound potentiometer and signal transistor came from Mouser Electronics. The 16 gauge copper stranded automotive wire between the two boxes came from Auto Zone.

 

    I purchased the second printing of this book in 1975 and the author did well by assuming the reader knows nothing about electricity. I have built many projects from the book and got them to work even thou I had to substitute some components.
 Home Made ThrottleI needed a second mainline throttle besides my MRC Control Master 20 that would look different. If you have two of the same kind, the controllers may accidentally get plugged into the others socket and that could be disastrous during operations. I built the 3 amp version from a old Kalmbach book called; “Practical Electronic Projects for Model Railroaders” by Perter J. Thorne and published in 1975. I modified the design by building a “Walk around Controller” that contains the potentiometer and push button for reverse. This design eliminates the track power from passing through the hand held, therefore needing only light gauge wires. The open box with the electronic components is the main throttle and the box at right is a 3 amp transformer. The four wire connector is from Mouser that allows the hand held to be moved other locations.