Re: gdt

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Ed Phillips <evp-at-pacbell-dot-net> 

"David Speck <dave-at-davidspeckmd-dot-org> wrote:
  > Any simple way to distinguish a powdered iron from a ferrite toroid
  > core?"

	All of the powdered iron cores I've seen are relatively soft (iron
powder in a plastic binder) and can be scratched with an awl or a scribe
without hurting the magnetic properties.  Ferrite materials are
glass-like, very hard, and easy to distinguish for that reason.  I'm
pretty sure ferrite cores will be more dense that powdered iron and that
measuring the density would be another method of ID.  I'd start by
trying the scratch test.  Either core may have a coating on the outside
so you have to make sure you're through that.

	Of course, if you have some to spare you can break one with a hammer
and look at the texture of the cross section

Ed