The Author traces the history of soft, magnetic materials from 1000 B.C. to the present time. He describes the work of Oersted and Faraday who invented the first transformer, and the gradual improvements in core material over the last 150 years. These cover soft iron, silicon iron, grain orientation, Hi-B steels and domain control by lasers and spark ablation. Amorphous metallic glasses are also detailed. Having spent a lifetime on nickel iron alloys, particularly Mumetal, he discusses design and characteristics of a wide range of audio transformers and magnetic shields.
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