July 29, 2010 Ferrite Core Transformers Ferrite is a ceramic material containing iron and other ferromagnetic elements in oxidation and crystallographic states, which gives the ferrite high magnetic permeability and very low electrical conductivity. The magnetic permeability of ferrite is much greater than that of air, and therefore, a great amount of energy is magnetically stored in the ferrite. This causes the inductance per unit length of ferrite-surrounded cable to be very high. << Back