Panel Mount Voltage Regulator / Knob

[Jeremy]

re: using an LM338.

I guess it depends as to whether or not current limiting is really needed and whether or not there is a need to supply a constant high current.

The power supply in that pic I posted is a good example. It uses a 5A linear voltage regulator IC rather similar to the LM 338, but only needs to deliver full current for short periods when charging up the 1.445 F, 20V capacitor bank. The same might be the case when driving steppers with PWM chopper control, for example, where the average current might actually be pretty low much of the time.

Jeremy

[irving2008]

I agree Jeremy. The point is that Lee wants a bench supply with a specific capability. If I was making a fixed supply then the LM338 is an ideal candidate. IF you want full output current to a given spec over a wide voltage range then linear regulators arent going to cut it. All depends on whats required. If Lee wants to reduce his expectations to 0 - 20v at .5A max guaranteed then the LM338 will do the job without overheating across the range. If he wants >1A output guaranteed then the LM338 isnt the way to go.... as the heatsink will be more expensive than the rest of it all together....

There is a secondary issue - is the goal just to produce something that'll 'just about do' or also to learn more about how to design a proper supply?

Irving...