Superseded by 393-1991. This publication specifies applicable tests to describe the significant properties of magnetic cores used in electronic applications. This publication is primarily concerned with magnetic cores of the type used in electronics transformers, magnetic amplifiers, inductors, and related devices. However, many of the test specified herein are general in scope and adaptable to magnetic cores used in many other applications. Standards covered by this publication include test for specifying or measuring, or both, permeability, core loss, apparent core loss, induction, hysteresis, theremal characteristics, and other properties of all commonly used types of magnetic cores.