Post subject: Self Capacitance of toroidal coil? Posted:
Thu Jul 26, 2007 10:16 am
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