Re: A good source of 5 and 12 power supplies

Norman Wootan ( normw@fastlane.net )
Tue, 17 Nov 1998 09:54:47 -0600

I salvage a lot of switching power supplies from big communication and computer
systems. I found that if you permanently connect a bleed resistor across the output
terminals the supply will stay perfectly regulated other wise you are right about
the possibilities of voltage runaway and failure due to lack of minimum load
reference voltage. Works for me. Norm

Marcelo Puhl wrote:

> > From: mbgupta@julian.uwo.ca
> > Subject: A good source of 5 and 12 power supplies
>
> > I was just fooling around with an old discarded PC when it occurred to me that
> > these clunkers have a wonderful compact switching power supply (SPS) fan and
> > all. I checked 2 PCs. The 220 Watt one can produce 8 amps at +12V and a
> > wapping 23 amps at +5V while the other 145 Watt supply produced about half
> > that!
> >
> > Chris Gupta
> >
>
> One thing that have to be watched : those power supplies sample the +5V for
> voltage regulation.
>
> If you only load the +12V output, the voltage drops a little.
>
> They can be modified to get the feedback voltage from the +12V output, but
> will loose the +5V regulation.
>
> ---
> Marcelo Puhl
> mark@plug-in.com.br
>
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