On Sat, May 10, 2003 at 05:43:17PM -0400, Marc Nicholas wrote:
> I'm building a 7805-based breadboard power supply...to be fed by one of
> those selectable "wall wart" 250mA transformers.

If it's "selectable" DC I'd go ahead and put in a diode between the
V+ in and the 7805 so that if you flip the polarity switch by accident
you get nothing instead of smoke.  Or a full rectifier if you like.

I would put the LED on.  Very handy.

I just built something like this a little while ago, 100uF on the input,
1uF ceramic on the output.  It fits on about 2/3rds of a small radio shack
board cut in half.  The other 1/3rd is the handle.  I bent up a header so
that the whole thing plugs into a power rail on a breadboard.

--
Ben Jackson
<ben@ben.com>
http://www.ben.com/

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