Finite Element Method Analysis for Video Heads under Eddy Current

Abstract

Using a Finite Element Method (FEM), a comparative investigation has been made to obtain the fundamental characteristics under a dynamic magnetic field of a metal head for use in a 8 mm VTR as a ferrite head. The FEM process includes the calculation procedures for magnetic saturation and eddy current.
As a result of the investigations, we found that: (1) the materials of higher saturation flux density are superior to the materials of lower one in producing stronger magnetic fields at a high recording density, in spite of eddy currents which were present; (2) the transmitting efficiency of the magnetic flux is constant, regardless of manetic motive force, permeability, and ferrite or metal; (3) the inductance of a VTR metal head is independent of the head gap depth in the video frequency range due to the presence of eddy currents.