Permeability

INTRODUCTION WHEN we use the term magnetic permeability we ordinarily think of it as defined by the ratio of B/H = (μ), where B is expressed in gausses and H in gilberts per centimeter. It is the ratio of the flux in a magnetic circuit produced by a given magnetizing force to the flux which would exist if there were no magnetic material present. If we are considering permeability values for inductions less than that at which maximum μ occurs the true permeability is given only when the material has been carefully demagnetized by applying gradually decreasing reversals of magnetizing force. Referring to the magnetization curve of Fig. 1 the permeability of the material at the induction P is given by the slope of the dotted straight line P O.