Esther & Fester Bestertester wrote:
I'd like to build a variable inductor with what I have around my shop (lots
of bits n' pieces, but no cores). I need it to work in the area of 20-30 mH,
1A, 25-30 KHz.

Is this something do-able? Is there something available off-the-shelf?

Suggestions of how to go about it would be greatly appreciated.

FBt

Take a transformer with sufficient mH, and use a constant current
on one of the unused windings to saturate the iron core to reduce
the mH rating.