Winston wrote:
The inductance of that coil fell significantly when you lopped
off the 'I' core, yes?

Yes and no, I suppose G. 'Though I did lop it off, I replaced it with
a shorting bar, so it shouldn't be drastically different.

Can you place a small value sense resistor in series with the
'common' line to your coil? The way I misunderstand magnetic
core saturation is that we expect a 'knee' where current begins
to increase in a nonlinear fashion in relation to applied
voltage. You could set your 'scope up as an X-Y display to
show this nonlinearity very clearly.

Funny you should mention that. I was going to do that and had dragged
my scope out, only to find it busted! Dang - those things are expensive
to fix!

Bob