Preface to First Edition

The purpose of this book is twofold: first, to provide a reference book on the design of transformers for electronic apparatus and, second, to furnish electronic equipment engineers with an understanding of the effects of transformer characteristics on electronic circuits. Familiarity with basic circuit theory and transformer principles is assumed. Conventional transformer design is treated adequately in existing books, so only such phases of it as are pertinent to electronic transformers are included here. The same can be said of circuit theory; only that which is necessary to an understanding of transformer operation is given. It is intended that in this way the book will be encumbered with a minimum of unnecessary material. Mathematical proofs as such are kept to a minimum, but the bases for quantitative results are indicated. The A.I.E.E. "American Standard Definitions of Electrical Terms" gives the meaning of technical words used. Circuit symbols conform to A.S.A. Standards Z32.5-1944 and Z32.10-1944.

Chapter headings, except for the first two, are related to general types of apparatus. This arrangement should make the book more useful. Design data are included which would make tedious reading if grouped together. For instance, the design of an inductor depends on whether it is for power or wave filter work, and the factors peculiar to each are best studied in connection with their respective apparatus.

Parts of the book are based on material already published in the Proceedings of the Institute of Radio Engineers, Electronics, and Communications. Much of it leans heavily upon work done by fellow engineers of the Westinghouse Electric Corporation, the warmth of whose friendship I am privileged to enjoy. To list all their names would be a difficult and inadequate expression of gratitude, but I should be guilty of a gross omission if I did not mention the encouragement given me by Mr. D. G. Little, at whose suggestion this book was written.

R. L.

July 1947