Dwayne Reid wrote:
>
> At 11:45 AM 3/5/03 -0500, PicDude wrote:
>
> >For (3), I've re-verified everything -- using a T130-3 (gray) core with
> >23 turns on the primary and 22 on the secondary.
> >
> >Latest results get me 1.3V at the output, with the LM2588 getting super
> >hot till the point that it burned my finger.
>
> This just cries out saying SATURATION.  I don't have data handy for that
> core, but right off the bat, go to 55 turns on the primary.  In other
> words, put the primary and secondary windings in series.

Can you explain what you mean here.  From the datasheets I have (and
let me point out right now that this is the first time I've come up
with the specs for a transformer), this should be quite doable.

I do have the windings "serial", if I understand you correctly.
No turn overlaps the other -- the primary takes up 180 degrees of
the core, and the secondary takes the other 180 degrees.  Here's
a photo...
http://www.narwani.org/neil/stuff/transformer-03.jpg

> Start with a lower voltage, if you can.

Possible with a few changes, but it also means I need to
find a 2-cell battery holder or similar.


> Are your switchers surviving?  Hope so!

I hope so, but for now, to eliminate variables, I'm
assuming that the used ones are dead.  Once I get a
working circuit, I'll re-test the used ones.

THere is a thermal shutdown on the chip, though I
question why it waits until it gets this hot.

Thanks,
-Neil.

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