A little bonus blog for the Experimenting with Magnetic Components contest: check calculations.
I want to make a toroidal inductor, with this NiZn ferrite core:
Laird 28B0375-400 ferrite cylindrical core, 81 ohm, 4.83 mm length, 5.08 mm inner diameter, 9.53 mm outer diameter
The inductor should be 60 µH.
I'm using an online calculator to get the right number of windings.
L is given. d is an attribute of the enameled wire you're using.
Most info (the green values) comes from the core's datasheet.
The µ comes from another document of Laird, their catalog of ferrite cores.
When calculating, the expected number of turns is 12:
I made this 12 windings inductor:
At 10 kHz, the meter reports 60 µH, at 100 kHz it's 57 µH
Close to the requested value.
If you're looking for the formulas: https://coil32.net/ferrite-toroid-core.html