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Date: Wed, 11 Nov 2009 12:31:24 +0000
From: Peter Dodd <g3ldo@ukonline.co.uk>
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Subject: LF: Ferrite characteristics
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Does anyone know of a method of measuring the characteristics 
(permeability) of ferrite cores?  I have a box of these most without any 
identification although I do have T200, 68-2T and T68-2s whose 
characteristics are known.

It occurs to me that you can make a tuned circuit and measure resonance 
with a GDO when a ferrite core is inserted into the inductance. A graph 
could be made of the different resonances with different cores, to 
extrapolate the unknowns.

However I think that ferrite bulk might be a problem. For example I 
guess the red T cores use the same material but would there be a 
difference between the T200 and the T68?

I have lots of material about ferrites in general - I just want to know 
what I have in my junk box. I am not interested in exact measurements, I 
just want to know if a core is suitable for a specific job.

Regards

Peter, G3LDO