What is a ferrite core?

Ferrite cores are dense, homogeneous ceramic structures made by mixing iron oxide (Fe2O3) with oxides or carbonates of one or more metals such as manganese, zinc, nickel, or magnesium.  They are pressed, then fired in a kiln to 1300o C, and machined as needed to meet various operational requirements.  Ferrites have an advantage over other types of magnetic materials due to their high electrical resistivity and low eddy current losses over a wide frequency range. These characteristics, along with high permeability, make ferrite ideal for use in applications such as high frequency transformers, wide band transformers, adjustable inductors and other high frequency circuitry from 10 kHz to 50 MHz. Ferrites are available in a wide variety of materials and geometries allowing for flexibility in magnetics and mechanical parameters.