12V regulator

12 Volt 20 Ampere Regulator circuit 

A heavy duty 13.8V power supply is a fine thing to have in the shack, but unless you acquire onesecondhand, is an expensive little beastie to buy. This means building one should be considered, not only for the cost savings, but also because you can brag about it on air to your mates. Of course, careful consideration must be given to the properties of the completed supply, and after talking to a few of my friends who have built their own and fallen into all the traps, here are the printable ones : RF proof, easy to make, commonly available parts used, but above all CHEAP.

Well, last things first. Breaking down the construction costs of a heavy duty regulated supply, they are in order:

The transformer (around $A80)

The main filter electrolytics – around $A80

The case – a metal case is well beyond the workshop capabilities of many amateurs and is quite expensive to buy (if you can).

The meter – around $A20-$27 (either digital or analogue)

The electronics – transistors, resistors, diodes, etc.

All the bits – fuseholders, terminals, switches, solder tags, nuts and bolts, power cords, etc.