View Single Post
  #20   Report Post  
Old October 10th 08, 12:37 PM posted to rec.radio.amateur.homebrew
[email protected] jimmie68@gmail.com is offline
external usenet poster
 
First recorded activity by RadioBanter: Dec 2007
Posts: 78
Default Switching power supplies question.

On Oct 9, 11:11*pm, Grumpy The Mule wrote:
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 sitehttp://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 :





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- Hide quoted text -


- Show quoted text -


From what I gather fro mthe website there is little danger in making L
to large within reason so I can expect my bits and pieces removed from
old power supplies to work. If they dont its probably because its too
small.


Jimmie