There are lots of web resources. Here's one:

http://www.amidoncorp.com/ace_iptcforrf.htm

And another: http://www.bytemark.com/

You can search for Amidon or Bytemark or Fair-Rite or Ferronics, and
also just search for 'powdered iron toroid' or 'ferrite toroid' and
find lots of things. Those links will take you more-or-less directly
to Al values for a wide range of cores. Just remember that inductance
goes as the square of the number of turns, so if Al is uH/100 turns,
the inductance will be Al*(your_turns/100)^2.

Cheers,
Tom


"J Shrum" wrote in message ...
Greetings,

Recently I bought a grab bag of mixed toroids from www.allelectronics.com .
I bought some T-37's and T-50's. The problem is... they're not color coded,
and not identified by mix. So I have mystery toroids T-37-?? and T-50-??...

The question is, is there a way to come up w/ a rough estimate of the mix
value? I wound some test coils and come up w/ these figures:

T-50 15turns 30awg = ~150uH
T-37 9turns 30awg = ~180uH

Perhaps there is a chart or something similar somewhere that I have
overlooked that will give me an idea.

Thanks for all assistance.

Jim Shrum - KC9FFX