The Natural Frequency of an Electric Circuit Having an Iron Magnetic Circuit

In radio or high audio frequency circuits cpntaining iron-core inductances, the eddy currents induced in the iron cause a marked change of effective inductance which is dependent on the frequency. Following the Steinmetz procedure, the author finds the magnetic flux density in a laminated iron core with alternating current excitation. He then derives expressions and tables for determining the natural frequency of circuits containing iron-core inductances. The results obtained are numerically illustrated.