"josephkk" wrote in message
...
You can find a small one in any computer PSU: they use a saturable core
(square B-H curve) to regulate the 3.3V supply off the 5V winding.
(Thanks
to separate regulation, and the high gain of the TL431, the 3.3V supply
has
substantially better regulation than the 5 or 12V rails!)

I have an issue he Square loop (square B-H curve) is not the same as
saturable core at all.


Well, square and narrow. Since NdFeB makes a bad reactor..

The classical "saturable reactor" consists of two magnetic paths and three
windings, imposing a CM-diff magnetic field between the two paths (usually
implemented as two toroids or the two arms of an E-core). This isn't to say
you can't get the same behavior (magnetic amplification, saturable reactor,
etc.) from a single winding, it's just arranged differently, and in
particular, diodes are used to steer the waveform as required.

Tim

--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms