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เนื้อหาย่อ : This book is about electrical circuits. It tells what they are, how to describe and analyze them, and what we can do with them. The style of presentation is in- formal. When mathematical rigor is called for, the presentation is unhurried. Systematic procedures for solving problems are emphasized. This algorithmic approach leads naturally to computer solutions. However, "pencil-and-paper" techniques are given equal prominence, especially in a first course on circuits, for the reason that students should first learn to solve problems by simple reason- ing rather than by the unreasoned use of the computer. The components of this book are a presentation of basic theory, a logical development of analysis techniques, and a repertoire of computer programs. Basic theory covers those properties of circuits that are immediately deducible from frst principles. These properties form the formal mathematical basis for writing equations describing the behavior of circuits. Analysis techniques include the formal solutions of circuits in the frequency and time domains as well as solutions "'by inspection," which are useful in practice. The computer programs range from one for finding a tree in a graph to one for the frequency analysis of a general linear circuit. They are written in FORTRAN IV and are completely docu- mented. Other computer programs will be written by the student as exercises. These programs are simple and limited in application, since it is felt that the student should devote his time to learning about circuits rather than to the debugging of his programs. To motivate the student and to show him what circuits can do, examples of circuits for use in communication systems and digital computers are given throughout the book. Thus, as early as in Chapter 2, the idea that a circuit can be used to extract a wanted signal in the presence of unwanted noise is presented. In Chapter 5, it is shown how diodes can be connected together to perform simple logic functions. In Chapters 4 and 8, circuits that are used in smoothing or delaying a signal are illustrated. To encourage students "'to do their own thing" and to get some appreciation of realistic circuits, a number of experiments are suggested at the end of each chap- ter. The purpose and general guidelines of each experiment are given, the details being left to the instructor. Problems are also given at the end of each chapter and are of three types: (1) exercises to give experience and confidence in analyzing circuits, (2) simple design problems to provide a taste of engineering practice, and (3) "fun" prob- lems, which may be difficult, but are interesting. Those in the last group are mostly for recreation, but some are designed to tempt the student to study circuit theory further. There are ten chapters. Chapter 1 presents the Kirchhoff voltage and current laws. The all-important question of the maximal number of independent voltage current equations is resolved here by using the concept of trees, chords, cut