Introduction to Electric Circuits -------------------------------------------------------- EIGHTH EDITION Richard C. Dorf U n iv e rs ity o f C a lifo rn ia James A. Svoboda C la rk s o n U n iv e rs ity WILEY John Wiley & Sons, Inc. VICE PRESIDENT AND EXECUTIVE PUBLISHER Donald Fowley ASSOCIATE PUBLISHER Dan Sayre SENIOR EDITORIAL ASSISTANT Katie Singleton PRODUCTION SERVICES MANAGER Dorothy Sinclair PRODUCTION EDITOR Janet Foxman EXECUTIVE MARKETING MANAGER Christopher Ruel CREATIVE DIRECTOR Harry Nolan DESIGNER Jim O’Shea MEDIA EDITOR Lauren Sapira PRODUCTION SERVICES Elm Street Publishing Services COVER IMAGES: Main Image: © Science Photo Library/Getty Images, Inc. Inset images: C SuperStock; Goodshot/Jupiter/Getty Images, Inc. This book was set in 10/12 pt in Times New Roman by Thomson Digital, and printed and bound by RRD Jefferson City. The cover was printed by RRD Jefferson City. 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Evaluation copies are provided to qualified academics and professionals for review purposes only, for use in their courses during the next academic year. These copies are licensed and may not be sold or transferred to a third party. Upon completion of the review period, please return the evaluation copy to Wiley. Return instructions and a free of charge return shipping label are available at wr\irw.com/go/returnlabel. Outside of the United States, please contact your local representative. Library of Congress Cataloging-in-Publication Data Dorf, Richard C. Introduction to electric circuits / Richard C. ISBN 978-0-470-52157-1 (cloth : alk.319'24— dc22 2009047257 ISBN 978-0-470-52157-1 Printed in the United States of America 10 9 8 7 6 5 4 3 2 T h e scien tific n a tu re o f th e o rd in a ry m a n Is to go o n o u t a n d d o th e b e st he can. —John Prine B ut, C a p ta in , I c a n n o t c h a n g e th e la w s o f p h y sics. Montogomery Scott (Scotty), USS Enterprise D e d ic a te d to o u r g ra n d c h ild re n : Ian C h risto p h e r B o ila rd , K y le E v e re tt S c h a fer, a n d G ra h a m H e n ry S c h a fe r an d H e a th e r L y n n S v o b o d a , Ja m e s H u g h S v o b o d a , Ja c o b A rth u r L eis, M a x w e ll A n d re w L e is, a n d J a c k M a n d lin L e ffle r About the Authors Richard C. Dorf, professor of electrical and computer engineering at the University of California, Davis, teaches graduate and undergraduate courses in electrical engineering in the fields of circuits and control systems. He earned a PhD in electrical engineering from the U. Naval Postgraduate School, an MS from the University of Colorado, and a BS from Clarkson University. Highly concerned with the discipline of electrical engineering and its wide value to social and economic needs, he has written and lectured internationally on the contributions and advances in electrical engineering. Professor Dorf has extensive experience with education and industry and is professionally active in the fields of robotics, automation, electric circuits, and communications. He has served as a visiting professor at the University of Edinburgh, Scotland, the Massachusetts Institute of Technology, Stanford University, and the University of California at Berkeley. A Fellow of the Institute of Electrical and Electronic Engineers and the American Society for Engineering Education, Dr. Dorf is widely known to the profession for his Modern Control Systems, eleventh edition (Prentice Hall, 2008) and The International Encyclopedia o f Robotics (Wiley, 1988). Dorf is also the coauthor of Circuits, Devices and Systems (with Ralph Smith), fifth edition (Wiley, 1992). Dorf editedthewidely used Electrical Engineering Handbook, third edition (CRC Press and IEEE press), published in 2008. Hislatest work is Technology Ventures, third edition (McGraw-Hill 2010). Svoboda is an associate professor of electrical and computer engineering at Clarkson University,where he teaches courses on topics such as circuits, electronics, and computer programming. He earned a PhD in electrical engineering from the University of Wisconsin at Madison, an MS from the University of Colorado, and a BS from General Motors Institute. Sophomore Circuits is one of Professor Svoboda's favorite courses. He has taught this course to 5,500 undergraduates at Clarkson University over the past 30 years. In 1986, he received Clarkson University’s Distinguished Teaching Award. Professor Svoboda has written several research papers describing the advantages of using nullors to model electric circuits for computer analysis. He is interested in the way technology affects engineering education and has developed several software packages for use in Sophomore Circuits. Preface The central theme of Introduction to Electric Circuits is the concept that electric circuits are part of the basic fabric of modem technology. Given this theme, we endeavor to show how the analysis and design of electric circuits are inseparably intertwined with the ability of the engineer to design complex electronic, communication, computer, and control systems as well as consumer products. APPROACH & O R G A N IZ A T IO N This book is designed for a one- to three-term course in electric circuits or linear circuit analysis and is structured for maximum flexibility. The flowchart in Figure 1 demonstrates alternative chapter organizations that can accommodate different course outlines without disrupting continuity. The presentation is geared to readers who are being exposed to the basic concepts of electric circuits for the first time, and the scope of the work is broad. Students should come to the course with the basic knowledge of differential and integral calculus. This book endeavors to prepare the reader to solve realistic problems involving electric circuits. Thus, circuits are shown to be the results of real inventions and the answers to real needs in industry, the office, and the home. Although the tools of electric circuit analysis may be partially abstract, electric circuits are the building blocks of modem society. The analysis and design of electric circuits are critical skills for all engineers. W H A T ' S N E W IN THE 8 TH E D I T I O N Increased use of PSpice K and MATLABH Significantly more attention has been given to using PSpice and MATLAB to solve circuits problems. It starts with two new appendixes, one introducing PSpice and the other introducing MATLAB. These appendixes briefly describe the capabilities of the programs and illustrate the steps needed to get started using them. Next, PSpice and MATLAB are used throughout the text to solve various circuit analysis and design problems. For example, PSpice is used in Chapter 5 to find a Thevenin equivalent circuit and in Chapter 15 to represent circuit inputs and outputs as Fourier series. MATLAB is frequently used to obtain plots of circuit inputs and outputs that help us see what our equations are telling us. MATLAB also helps us with some long and tedious arithmetic. For example, in Chapter 10, MATLAB helps us do the — - P r e fa c e Matrices, Color Determinants Code ----"A. 3 4 1 2 METHODS OF RESISTIVE ELECTRIC CIRCUIT CIRCUITS ANALYSIS OF W' ELEMENTS RESISTIVE CIRCUIT VARIABLES CIRCUITS Complex Numbers FIGURE 1 Flow chart showing alternative paths through the topics in this textbook. complex arithmetic to analyze ac circuits and, in Chapter 14, MATLAB helps with the partial fraction required to find inverse Laplace transforms. O f course, there’s more to using PSpice and MATLAB than simply running the programs. W e pay particular attention to interpreting the output o f these computer programs and checking it to m ake sure it is correct. Frequently, this is done in the section called, “ How Can We Check . ” included in every chapter. For example, Section 8.9 shows how to interpret and check a PSpice transient response, and Section 13.7 shows how to interpret and check a frequency response produced using M ATLAB or PSpice. Revisions to Improve Clarity Chapter 15 covering the Laplace transform and the Fourier series and transform , Chapters 14 and 15, have been largely rewritten, both to improve clarity o f exposition and to significantly increase coverage of MATLAB and PSpice. In addition, revisions have been made throughout the text to improve clarity. Sometimes these revisions are small, involving sentences or paragraphs. O ther, larger revisions involve pages or even entire sections. More Problems The 8 th edition contains 1 20 new problems, bringing the total number o f problems to more than 1,3 50. This edition uses a variety of problem types and they range in difficulty from simple to challenging, including: Preface PSpice 16 FILTER CIRCUITS 1 13 14 15 FREQUENCY THE FOURIER TWO-PORT RESPONCE LAPLACE SERIES NETWORKS TRANSFORM AND FOURIER TRANSFORM 4 17 THE TWO-PORT OPERATIONAL NETWORKS AMPLIFIER Legend: Primary flow . O Chapter Appendix Optional flow Straightforward analysis problems. Analysis of complicated circuits. Simple design problems. (For example, given a circuit and the specified response, determine the required RLC values.) Compare and contrast, multipart problems that draw attention to similarities or differences between two situations. • MATLAB and PSpice problems. (Given some specifications, devise a circuit that satisfies those specifications. How Can We Check . ? (Verify that a solution is indeed correct.) FEATURES RETAINED FROM PREVIOUS EDITION S Introduction Each chapter begins with an introduction that motivates consideration o f the material o f that chapter. Examples Because this book is oriented toward providing expertise in problem solving, we have included m ore than 260 illustrative examples. Also, each example has a title that directs the student to exactly w hat is being illustrated in that particular example. Various methods o f solving problems are incorporated into select exam ples. These cases show students that multiple methods can be used to derive sim ilar solutions or, in some cases, that m ultiple solutions can be correct. This helps students build the critical thinking skills necessary to discern the best choice between multiple outcomes. Design Examples, a Problem-Solving Method, and "How Can We Check . " Sections Each chapter concludes with a design example that uses the methods o f that chapter to solve a design problem. A formal, five-step problem-solving method is introduced in Chapter 1 and then used in each o f the design examples. An important step in the problem-solving method requires you to check your results to verify that they are correct. Each chapter includes a section entitled ‘ ‘How Can We Check . ” that illustrates how the kind o f results obtained in that chapter can be checked to ensure correctness. Key Equations and Formulas You will find that key equations, formulas, and important notes have been called out in a shaded box to help you pinpoint critical information. Summarizing Tables and Figures The procedures and m ethods developed in this text have been sum m arized in certain key tables and hgures.
