Core material selection to achieve desired inductance of a coil?

[hobbs125]

Hello everyone,

I am trying to make a coil with the exact specs as the original. I have all the info I need except the actual core material used. I have all the measurements of the core and coil including: Wire gauge, # of turns and turns per layer,Bobbin dimensions, inductance without the core, inductance with the core, operating frequency range etc. I believe the core material is ferrite with a permeability of around 1,000 but I'm not exactly sure.

How can I determine the permeability of the core I need?

 

[berkeman]

Hello everyone,

I am trying to make a coil with the exact specs as the original. I have all the info I need except the actual core material used. I have all the measurements of the core and coil including: Wire gauge, # of turns and turns per layer,Bobbin dimensions, inductance without the core, inductance with the core, operating frequency range etc. I believe the core material is ferrite with a permeability of around 1,000 but I'm not exactly sure.

How can I determine the permeability of the core I need?

There are two main things that you need to quantify, IMO. You need the A-sub-L of the material, and the saturation flux density.

The A-sub-L is the inductance per turn squared. You can measure this directly, and correlate that to the datasheet numbers that you look up.

The saturation flux density is also fairly easy to measure.

 

[Carl Pugh]

The easy way to make an inductor is to select a core with higher permeability than required and then add gaps to the core