[Amps] 12V 120A Switcihng Power supply?

Jim Strohm jstrohm@texas.net
Sun, 31 Mar 2002 15:13:10 -0600

That's not to say we couldn't design one that used commonly available parts
and was cheap to build in a modular fashion.

2N3055s will comfortably switch to 20 kHz at 60 V or 10A (200W diss max).
Premium versions of this transistor will go to much higher voltages.

Most of us have this sort of stuff in our junkboxes  -- my elmer showed me
how easy it was to make a switch-mode power supply by gathering up a
jandful of junk an some alligator clip test leds -- we established
oescillation with a CHEAP LC circuit, then diddled with bias for a
semi-optimized output.

No, we did NOT touch the non-heatsinked transistor afterwards, but he
demonstrated how easy it was to get something rolling.

It would be almost trivial to design an N+1 redundant supply to build up to
the desired current in 20-amp blocks, from junk.  The switch-mode PS in the
handbook is nice and efficient, but it contains a great deal of unobtainium
as well as some technical mistakes in the first edition that cause the
unobtainium to sustain fission.

I'm not sure if these technical errors were ever corrected. I *DO* know
that they were carried from the QST article where they first appeared into
the next edition of the handbook, and were mentioned in the first errata
published for that edition of the handbook.

I guess it's time to add yet another project to the list.

This one should be finished about 2006.


Phil Levin W2GE <w2ge@arrl.net> sez --

>I don't think such a beast exists....
>-----Original Message-----
>From: amps-admin@contesting.com [mailto:amps-admin@contesting.com] On
>Behalf Of K2KW@prodigy.net
>Sent: Saturday, March 30, 2002 10:00 AM
>To: jeff millar; Amps@contesting.com
>Subject: Re: [Amps] 12V 120A Switcihng Power supply?
>Jeff & all.
>Sorry I wasn't more specific on my request.
>I want to create a lightweight DXpedition amplifier
>package.  I will NOT be using the amp mobile, but
>running off of standard 110/220v power.