Effective dimensions of binocular ferrite core

[Telegraph]

I was trying to do calculations on a ferrite binocular core.  I found formulas to calculate the permeability that require the effective area and magnetic path length.  For a regular toroid, or bead, that appears to be straight forward.  What about a binocular (mulit-aperture core)?  I found documentation for more complex arrangements, such as, E-cores but nothing on the binocular format.

[richard.cs]

Treat is as two independent tube cores, each like a long bead.

[igor78]

This topic comes first in websearch. For future readers:

Page 2 here
https://www.tdk-electronics.tdk.com/inf/80/db/fer/double_aperture_cores.pdf

Notice the dimension units there mm^-1

Also see https://owenduffy.net/blog/?p=14712 "Geometry factors for some common Fair-rite binocular ferrite cores"

Core	BN designation	ΣA/l (m)
2843000202	BNxx-202	0.00288
2843000302	BNxx-302	0.00211
2843001502	BNxx-1502	0.00139
2843002402	BNxx-2402	0.00154
2843010402		0.00308

[jonpaul]

for,a shield EMI bead, see mfg specs,
for use,as balun, the exact spec is seldom important

We just wind and test on a high frequency RLC or impedance analyzer
j

[jonpaul]

beside TDK try old Fair-Rite, EPCOS, Philips data.

j