View Single Post
  #19   Report Post  
Old October 10th 08, 04:11 AM posted to rec.radio.amateur.homebrew
Grumpy The Mule Grumpy The Mule is offline
external usenet poster
 
First recorded activity by RadioBanter: Sep 2008
Posts: 87
Default Switching power supplies question.


Cobbling stuff together is lots of fun. From Pressman's
book you can figure out the inductor value.

I'm guessing a powdered iron toroid from the output of a PC
power supply would work. Probably need quite a few turns of
moderate size ~22AWG magnet wire. Maybe 300 turns... ugh.
Makes my hands hurt just thinking about it. I guess a bobbin
wound inductor would be better. Gapped ferrite isn't bad!

Check this site http://schmidt-walter.eit.h-da.de/smps_e/smps_e.html

I try to stay away from dumpsters but if I see anything electrical
or electronic in one it's neigh impossible.



wrote in
:

Like you said I like to Frankenstien things. I have a filter from
another power supply but I am not sure how well it will work
as it was designed for about 25 amps. Basically thats a bridge I will
jump off of when I come to it. Right now I am having enough trouble
finding an old PC power supply I can get a transformer from. Its hard
to believe about a couple of months ago I tossed about a dozen of
them. Last time I listen to my wife. I do have a couple of
transformers from some old Lambda power supplies. Thes are some really
nice ones probably capable of handling a couple of Kwatts. Im not
ready to experiment with them yet. Although this is learning by
destuction it's cautious destruction. I will probably take a trip down
to the local computer place this weekend and do a little dumpster
diving or make a run on the goodwill store and see what I can get for
$10. IF you havent figured it out by now I love building things from
others discards. When I was in high schooI I built a killer stereo, I
thought at the time, from old stuff I found in the dump that was the
envy of most of my friends. Ive enjoyed doing it ever since.

Jimmie