On December 16, ajp166 wrote:
  The older large ferrite core is easier to work with
though
 much slower.  The bigger cores produce a larger output
 when they switch but the cycle times are in the
 3-5uS range.  The later is helpful for demos as nothing
 is too fast. 
  I wonder if it would be possible (and practical) to use a
microcontroller, perhaps a PIC, to act as a core controller.  Use the
A/D and D/A hardware to handle the drive and sense stuff, and do all
the timing in firmware...making it easily tweakable.
  That would be something I'd be up for trying...if I can find a chunk
of core of low enough density to trace the wiring in.  There are some
nice low-density planes on eBay right now, but they are priced WAY too
high in my opinion.
     -Dave
--
Dave McGuire
St. Petersburg, FL         "Less talk.  More synthohol." --Lt. Worf