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Post subject: Self Capacitance of toroidal coil? Posted: Thu Jul 26, 2007 10:16 am
Joined: Thu Jul 26, 2007 9:25 am
Location: Roskilde, Denmark
1) Does anyone know how to model the self capacitance between windings of a toroidal coil wounded on a nonmagnetic ring? or a ferrite ring?
Let's say that we have 40 turns, outer core diameter is 35mm and the relative permittivity of the ferrite is about 15.
I am interested in a simple model of the self capacitance as a limiting factor of the actual measured inductance at a frequency well below the upper limit due to the unwanted LC-effect.
2) Will the self-cap in air with close distance between turns (<1mm) or the self-cap across the core with larger distance (>6mm) be the most contributing cap?
3) How will self-cap change if the coil is wounded in 2 layers as opposed to one layer?
4) What about stray capacitance at low frequencies: f<10MHz? or f<1MHz?
Will it matter?
Best regards and
Vy 73 de OZ7ACS aka JPH