From: "Christopher R. Carlen"
Subject: Re: Variable PSU
Date: Mon, 23 Dec 2002 09:57:14 -0800
Organization: Sandia National Laboratories, Albuquerque, NM USA
NNTP-Posting-Date: Mon, 23 Dec 2002 16:55:44 +0000 (UTC)
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> Hi there gang!
> I need some help on a schematic that I'm looking for. I wanna build a
> variable power supply for the workshop (1.5v - 30v) apprx. If it has
> variable current that'll be great as well. Another thing, when i've
> built it, how would I connect a voltmeter and ammeter to it to make
> ACCURATE readings.
> Any help would be greatly appreciated.
I built my own PS for home, a dual 1.2-30V 5A beast. I thought it would
be cheaper than buying one, which was probably true. But like most
things I do very slowly, it took many months to finish (with just a few
hours a week to spare to build it), and it was a bit of a pain in the butt.
Next time, I'll just buy one. Of course I didn't have a decent job at
the time to afford one either. But if you aren't interested in
*learning* or building for the sake of having the feeling "I build it
myself" then spare yourself the fuss and buy one.
Other than that, I'd suggest the LM338K for a 5A power supply, and there
's a LM350 for 3A, and LM317 for 1.5A. These are the easy way to go,
but not easy to switch constant voltage/current modes. For that, look
in AoE for a nice schematic of a lab supply that makes 2.5A, adjustable
down to 0V and up to 30V, and can also be a constant current supply.
Christopher R. Carlen
Principal Laser/Optical Technologist
Sandia National Laboratories CA USA