An Amateur Radio Power Supply 13.8V 30-40A with short circuit protection - all you need to run the most common 100-200W Amateur Radio transceivers...!


  1. Foreword
  2. Functions
  3. Project schematic, PCB layouts and data sheets
  4. Pictures


My homebrewed 13.8V 30-40A primary Power Supply, with built in short circuit protection, build on POWER FET transistors.


This is the primary Power Supply for my Amateur Radio Shacks transceiver equipment. The Power Supply is build around the LM723 controller and four BUZ24 (or IRF150) power N-Channel FET transistors. FET transistors are used because of the simplicity of controlling the current through these transistors, it's simply voltage controlled, and because of the low power consumption of the controller board. The Power Supply is initially based on ideas from TF3MA.



Project schematics, PCB layouts and data sheets


The Printed Circuit Board (PCB) and the layout

...from another angle

...a close up of the controller PCB

Here are the holes for connection to the four FET's gate and source.
The FET's drain is connected directly to the '+' pole of
the 6 x 10.000 electrolyte capacitors. The 15V zener diodes,
between source and gate, are not mounted when this picture
has been taken.

Mounting two of the four BUZ24 FET's at one of the two
heat sinks. All four FET's are isolated from the heat sink
by slices of silicone
between the FET's and the heat sink and
small pieces of plastic between the screws and the heat sink.

Two FET's mounted at the rear of the heat sink

An inside look at the Power Supply. At the left is a transformer
for powering the controller board next to it. In the middle
are the 6 x 10.000 uF electrolyte capacitors. At the right is a
part of the heavy duty ring transformer.

A look at the rear of the second hand chassis of my Power
Supply - before mounting of the two heat sinks loading
two FET's both.

A look inside the Power Supply from another angle...

...yet another picture from the inside...

The two power resistors in the back are two of the 0.1 ohm
connected to each FET's source.

An overview of the inside of the Power Supply

The front of the Power Supply. Switch S2 is in amps and the
Power Supply is not loaded in this situation - that's why
the met
er isn't showing anything.

Another picture of the front of the 13.8V 30-40A Power
Supply using N-Channel FET power transistors.