Peter,
the best aid I know is the mini Ring Core Calculator V1.2
which is freeware
http://www.dl5swb.de/html/mini_ring_core_calculator.htm
It is a fantastic tool for known and unknown toroid materials.
For determining the µrel of an unknown toroid you wind a few turns
on it,measure the inductance,enter the inductance and the physical
dimensions of the core into the program and it gives you all you want
to know including µrel.
And the results are really correct.
Very handy with Amidon toroids,too.
73
Clemens
DL4RAJ
----- Original Message -----
From: "Peter Dodd" <[email protected]>
To: <[email protected]>
Sent: Wednesday, November 11, 2009 1:31 PM
Subject: LF: Ferrite characteristics
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
|
