On Sat, 21 Apr 2007 05:49:50 -0500, "amdx" wrote:

snip

It'd guess that it would be hard to get that tiny winding to saturate
the gapped toroid, and cooling would be nasty.

The toroid is not gapped, it is placed in a pot core gap.

The illustration sort of looked like it was. I suppose it was just
necked down, which is a partial gap. Still, he won't get a lot of
ampere-turns in a structure like that, not without frying the wire.

John


Yes, I now see the confusion, The toroid is necked down, it is not gapped.

If the toroid is not completely enclosed in the control winding, you'l
get unpredictable results.

A necked toroid (as drawn) that actually made physical contact with
the potcore, would share flux with the pot core body, reducing the
ability of the coil to saturate the ferrite in the area of contact.

Only the relatively small volume enclosed by the winding could be
garanteed to saturate.

RL