- Information
- AI Chat
Introduction TO Elecrtical Engineering
Electrical engineering (EET301)
Recommended for you
Preview text
INTRODUCTION TO ELECRTICAL ENGINEERING
The aim of this chapter is to introduce electrical engineering. The chapter is organized to provide the newcomer with a view of the different specialties making up electrical engineering and to place the intent and organization of the book into perspective. Perhaps the first question that surfaces in the mind of the student approaching the subject is, Why electrical engineering? Since this book is directed at a readership having a mix of engineering backgrounds (including electrical engineering), the question is well justified and deserves some discussion. The chapter begins by defining the various branches of electrical engineering, showing some of the interactions among them, and illustrating by means of a practical example how electrical engineering is intimately connected to many other engineering disciplines. Section 1 introduces the Engineer-in-Training (EIT) national examination. In Section 1 the fundamental physical quantities and the system of units are defined, to set the stage for the chapters that follow. Finally, in Section 1 the organization of the book is discussed, to give the student, as well as the teacher, a sense of continuity in the development of the different subjects covered in Chapters 2 through 14.
1 ELECTRICAL ENGINEERING
The typical curriculum of an undergraduate electrical engineering student includes the subjects listed in Table 1. Although the distinction between some of these subjects is not always clear-cut, the table is sufficiently representative to serve our purposes. Figure 1 illustrates a possible interconnection between the disciplines of Table 1. The aim of this book is to introduce the non-electrical engineering student to those aspects of electrical engineering that are likely to be most relevant to his or her professional career. Virtually all the topics of Table 1 will be touched on in the book, with varying degrees of emphasis. Example 1 illustrates the pervasive presence of electrical, electronic, and electromechanical devices and systems in a very common application: the automobile. As you read through the examples, it will be instructive to refer to Figure 1 and Table 1.
Table 1 Electrical engineering disciplines Circuit analysis Electromagnetics Solid-state electronics Electric machines Electric power systems Digital logic circuits Computer systems Communication systems Electro-optics Instrumentation systems Control systems
EXAMPLE 1 Electrical Systems in a Passenger Automobile Afamiliar example illustrates how the seemingly disparate specialties of electrical engineering actually interact to permit the operation of a very familiar engineering system: the automobile. Figure 1 presents a view of electrical engineering systems in a modern automobile. Even in older vehicles, the electrical system—in effect, an electric circuit—plays a very important part in the overall operation. (Chapters 2 and 3 describe the basics of electric circuits.) An inductor coil generates a sufficiently high voltage to allow a spark to form across the spark plug gap and to ignite the air-fuel mixture; the coil is supplied by a DC voltage provided by a lead-acid battery. (Ignition circuits are studied in some detail in Chapter 5.) In addition to providing the energy for the ignition circuits, the battery supplies power to many other electrical components, the most obvious of which are the lights, the windshield wipers, and the radio. Electric power (Chapter 7) is carried from the battery to all these components by means of a wire harness, which constitutes a rather elaborate electric circuit (see Figure 2 for a closer look). In recent years, the conventional electric ignition system has been supplanted by electronic ignition; that is, solid-state electronic devices called transistors have replaced the traditional breaker points. The advantage of transistorized ignition systems over the conventional mechanical ones is their greater reliability, ease of control, and life span (mechanical breaker points are subject to wear). You will study transistors and other electronic devices in Chapters 8, 9, and 10. Other electrical engineering disciplines are fairly obvious in the automobile. The on-board radio receives electromagnetic waves by means of the antenna, and decodes the communication signals to reproduce sounds and speech of remote origin; other common communication systems that exploit electromagnetics are CB radios and the ever more common cellular phones. But this is not all! The battery is, in effect, a self-contained 12-VDC electric power
interfaces (e., based on the “Bluetooth” standard) and satellite radio and driver assistance systems, such as the GM “OnStar” system.
1 FUNDAMENTALS OF ENGINEERING
EXAM REVIEW
To become a professional engineer it is necessary to satisfy four requirements. The first is the completion of a B. degree in engineering from an accredited college or university (although it is theoretically possible to be registered without having completed a degree). The second is the successful completion of the Fundamentals of Engineering (FE) Examination. This is an eight-hour exam that covers general undergraduate engineering education. The third requirement is two to four years of engineering experience after passing the FE exam. Finally, the fourth requirement is successful completion of the Principles and Practice of Engineering or Professional Engineer (PE) Examination. The FE exam is a two-part national examination, administered by the National Council of Examiners for Engineers and Surveyors (NCEES) and given twice a year (in April and October). The exam is divided into two four-hour sessions, consisting of 120 questions in the four-hour morning session, and 60 questions in the four-hour afternoon session. The morning session covers general background in 12 different areas, one of which is Electricity and Magnetism. The afternoon session requires the examinee to choose among seven modules—Chemical, Civil, Electrical, Environmental, Industrial, Mechanical, and Other/General engineering. One of the aims of this book is to assist you in preparing for the Electricity and Magnetism part of the morning session. This part of the examination consists of approximately 9 percent of the morning session, and covers the following topics: A. Charge, energy, current, voltage, power. B. Work done in moving a charge in an electric field (relationship between voltage and work). C. Force between charges. D. Current and voltage laws (Kirchhoff, Ohm). E. Equivalent circuits (series, parallel). Chapter 1 Introduction to Electrical Engineering 5 F. Capacitance and inductance. G. Reactance and impedance, susceptance and admittance. H. AC circuits. I. Basic complex algebra. Appendix C (available online) contains review of the electrical circuits portion of the FE examination, including references to the relevant material in the book. In addition, Appendix C also contains a collection of sample problems—some including a full explanation of the solution, some with answers supplied separately. This material has been derived from the author’s experience in co-teaching the FE exam preparation course offered to Ohio State University seniors
1 SYSTEM OF UNITS
This book employs the International System of Units (also called SI, from the French Système International des Unités). SI units are commonly adhered to by virtually all engineering professional societies. This section summarizes SI units and will serve as a useful reference in reading the book. SI units are based on six fundamental quantities, listed in Table 1. All other units may be derived in terms of the fundamental units of Table 1. Since, in practice, one often needs to describe quantities that occur in large multiples or small fractions of a unit, standard prefixes are used to denote powers of 10 of SI (and derived) units. These prefixes are listed in Table 1. Note that, in general, engineering units are
expressed in powers of 10 that are multiples of 3. For example, 10-4 s would be referred to as 100 × 10-6 s, or 100 μs (or, less frequently, 0 ms).
Introduction TO Elecrtical Engineering
Course: Electrical engineering (EET301)
University: Rashtrasant Tukadoji Maharaj Nagpur University
