On Wed, 21 Apr 2004 17:55:20 -0500, "J Shrum" wrote:

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-??...

If they are not color coded then I guess they aren't Amidon toroids,
at least all the Amidon toroids I have seen were color coded, Amidon
does have all the specifications for all their toroids posted on their website
though:
http://www.amidoncorp.com/aai_productselection.htm


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.

If you are running Windows, you can use this program to do
quick inductance calculations for many different toroids types:
http://www.qsl.net/dl5swb/minirk_e.htm , and to get specs on
different toroid types. A real time saver for calculating the inductance values
and it also shows the Inductance Index for each toroid and the frequency
bandwidth for that composition type, which might help you to get a better
idea of the composition type of your toroids. I think it will still be hard to determine
the composition types for certain, although the different composition types do have
different Inductance Index values for the same size toroid.