This calculator estimates the permeability of a ferrite core at HF from ΣA/l or Σl/A and R,X measurement of a very small number of turns.
SVN:
The calculator does not do a lot of error checking, if you enter nonsense, it will produce nonsense. NaN means not a number, check the input values.
The model used is of a simple parallel resonant circuit to represent the inductance of the turns, loss due to core losses as implied by complex permeability, and equivalent stray capacitance. The calculator does not model dimensional resonance effects that occur in some ferrite materials (other than to the extent captured by µ', µ'').
Inductors exhibit a self resonance, the effect of which can be estimated by shunting the calculated series R,Xl with an equivalent capacitance, usually in the region of 2 to 10pF (depending on the physical layout, turns spacing etc).
The calculator assumes sharp corners on the toroid, radiused corners will reduce impedance and Leq somewhat. Conductor loss is ignored as for most practical ferrite cored inductors at RF, the core losses dwarf copper loss.
| Input field | Meaning |
| Frequency | The frequency at which to calculate Xl and R |
| µ' | Real part of the complex relative permeability |
| µ'' | Imaginary part of the complex relative permeability |
| Turns | Number of turns |
| Cs | Estimated equivalent stray capacitance |
| Version | Date | Description |
| 1.01 | 25/11/2022 | Initial. |
| 1.02 | ||
| 1.03 | ||
| 1.04 | ||
| 1.05 |