Panel Mount Voltage Regulator / Knob

[Robin Hewitt]

For my DC suds pump speed control I used an LM338T, just google for LM338 and get the data sheet with circuit diagrams.

Up to 5 Amps, needs a few extra components, but with a bit of jiggery pokery you can solder them on to the pins and enclose with shrink wrap.

Bit of an industry standard, costs a quid.

[irving2008]

For my DC suds pump speed control I used an LM338T, just google for LM338 and get the data sheet with circuit diagrams.

Up to 5 Amps, needs a few extra components, but with a bit of jiggery pokery you can solder them on to the pins and enclose with shrink wrap.

Bit of an industry standard, costs a quid.

LM338 is good device for a fixed supply, but not ideal for a variable unit unless you have a big heatsink. if you want 0 - 25v off a 30v supply at 5A then you are outside its thermal characteristics - it can dissipate 25W max so thats 5A at 25v output, dropping to 1A at 5v output. Has the advantage of simplicity tho with only 5 other parts needed (excluding bridge rec and smoothing cap)

Although slightly more complex (as in needing 6 more parts) a switch mode supply based on LT series devices needs no heatsink and gives variable current limit as well as voltage.

A similar spec bench supply on ebay is about £60 so by the time you bought the bits and made it up and boxed it for safety its marginal to make them really... except for the fun/satisfaction of knowing you did it yourself.