Sixth Edition, last update July 25, 2007 - ibiblio

1 Sixth edition , last update july 25, 20072 Lessons In Electric Circuits, Volume II ACBy Tony R. KuphaldtSixth edition , last update july 25, 2007ic 2000-2020, Tony R. KuphaldtThis book is published under the terms and conditions of the Design Science License. Theseterms and conditions allow for free copying, distribution,and/or modification of this documentby the general public. The full Design Science License text is included in the last an open and collaboratively developed text, this book is distributed in the hope thatit will be useful, but WITHOUT ANY WARRANTY; without even theimplied warranty ofMERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See theDesign ScienceLicense for more in its entirety as part of the Open Book Project collection HISTORY First edition : Printed in June of 2000.

2 Plain-ASCII illustrations for universal computerreadability. Second edition : Printed in September of 2000. Illustrations reworked in standard graphic(eps and jpeg) format. Source files translated toTexinfoformat for easy online and printedpublication. Third edition : Equations and tables reworked as graphic images rather than plain-ASCII text. Fourth edition : Printed in November 2001. Source files translated is a simple markup language designed to easily convert to other markups likeLATEX, HTML, or DocBook using nothing but search-and-replace substitutions. Fifth edition : Printed in November 2002. New sections added, and error correctionsmade, since the fourth edition . Sixth edition : Printed in June 2006. Added CH 13, sections added, and error correctionsmade, figure numbering and captions added, since the fifth BASIC AC What is alternating current (AC)?

3 AC waveforms.. Measurements of AC magnitude.. Simple AC circuit calculations.. AC phase.. Principles of radio.. Contributors.. 252 COMPLEX Introduction.. Vectors and AC waveforms.. Simple vector addition.. Complex vector addition.. Polar and rectangular notation.. Complex number arithmetic.. More on AC polarity .. Some examples with AC circuits.. Contributors.. 553 REACTANCE AND IMPEDANCE AC resistor circuits.. AC inductor circuits.. Series resistor-inductor circuits.. Parallel resistor-inductor circuits.. Inductor quirks.. More on the skin effect .. Contributors.. 794 REACTANCE AND IMPEDANCE AC resistor circuits.. AC capacitor circuits.. Series resistor-capacitor circuits.

4 Parallel resistor-capacitor circuits.. Capacitor quirks.. Contributors.. 975 REACTANCE AND IMPEDANCE R, L, AND Review of R, X, and Z.. Series R, L, and C.. Parallel R, L, and C.. Series-parallel R, L, and C.. Susceptance and Admittance.. Summary.. Contributors.. 1206 An electric pendulum.. Simple parallel (tank circuit) resonance.. Simple series resonance.. Applications of resonance.. Resonance in series-parallel circuits.. Q and bandwidth of a resonant circuit.. Contributors.. 1517 MIXED-FREQUENCY AC Introduction.. Square wave signals.. Other waveshapes.. More on spectrum analysis.. Circuit effects.. Contributors.. 1888 What is a filter?.. Low-pass filters.. High-pass filters.

5 Band-pass filters.. Band-stop filters.. Resonant filters.. Summary.. Contributors.. 2159 Mutual inductance and basic operation.. Step-up and step-down transformers.. Electrical isolation.. Phasing.. Winding configurations.. Voltage regulation.. Special transformers and applications.. Practical considerations.. Contributors.. 281 Bibliography.. 28110 POLYPHASE AC Single-phase power systems.. Three-phase power systems.. Phase rotation.. Polyphase motor design.. Three-phase Y and Delta configurations.. Three-phase transformer circuits.. Harmonics in polyphase power systems.. Harmonic phase sequences.. Contributors.. 34511 POWER Power in resistive and reactive AC circuits.. True, Reactive, and Apparent power.

6 Calculating power factor.. Practical power factor correction.. Contributors.. 36512 AC METERING AC voltmeters and ammeters.. Frequency and phase measurement.. Power measurement.. Power quality measurement.. AC bridge circuits.. AC instrumentation transducers.. Contributors.. 406 Bibliography.. 40613 AC Introduction.. Synchronous Motors.. Synchronous condenser.. Reluctance motor.. Stepper motors.. Brushless DC motor.. Tesla polyphase induction motors.. Wound rotor induction motors.. Single-phase induction motors.. Other specialized motors.. Selsyn (synchro) motors.. AC commutator motors.. 479viCONTENTSB ibliography.. 48214 TRANSMISSION A 50-ohm cable?.. Circuits and the speed of light.. Characteristic impedance.

7 Finite-length transmission lines.. Long and short transmission lines.. Standing waves and resonance.. Impedance transformation.. Waveguides.. 529A-1 ABOUT THIS BOOK537A-2 CONTRIBUTOR LIST541A-3 DESIGN SCIENCE LICENSE549 INDEX552 Chapter 1 BASIC AC What is alternating current (AC)?.. AC waveforms.. Measurements of AC magnitude.. Simple AC circuit calculations.. AC phase.. Principles of radio.. Contributors.. What is alternating current (AC)?Most students of electricity begin their study with what is known asdirect current(DC), whichis electricity flowing in a constant direction, and/or possessing a voltage with constant is the kind of electricity made by a battery (with definite positive and negative terminals),or the kind of charge generated by rubbing certain types of materials against each useful and as easy to understand as DC is, it is not the only kind of electricity in sources of electricity (most notably, rotary electro-mechanical generators) naturallyproduce voltages alternating in polarity, reversing positive and negative over time.

8 Either asa voltage switching polarity or as a current switching direction back and forth, this kind ofelectricity is known as Alternating Current (AC): the familiar battery symbol is used as a generic symbol for any DC voltage source,the circle with the wavy line inside is the generic symbol forany AC voltage might wonder why anyone would bother with such a thing as AC. It is true that insome cases AC holds no practical advantage over DC. In applications where electricity is usedto dissipate energy in the form of heat, the polarity or direction of current is irrelevant, solong as there is enough voltage and current to the load to produce the desired heat (powerdissipation). However, with AC it is possible to build electric generators, motors and power12 CHAPTER 1.

9 BASIC AC THEORYIIDIRECT CURRENT(DC)ALTERNATING CURRENT(AC)IIFigure :Direct vs alternating currentdistribution systems that are far more efficient than DC, andso we find AC used predominatelyacross the world in high power applications. To explain the details of why this is so, a bit ofbackground knowledge about AC is a machine is constructed to rotate a magnetic field around aset of stationary wire coilswith the turning of a shaft, AC voltage will be produced across the wire coils as that shaftis rotated, in accordance with Faraday s Law of electromagnetic induction. This is the basicoperating principle of an AC generator, also known as analternator: +-LoadIINSL oadno current!no current!LoadNSNLoadS-+IIStep #1 Step #2 Step #3 Step #4 Figure :Alternator WHAT IS ALTERNATING CURRENT (AC)?

10 3 Notice how the polarity of the voltage across the wire coils reverses as the opposite poles ofthe rotating magnet pass by. Connected to a load, this reversing voltage polarity will create areversing current direction in the circuit. The faster the alternator s shaft is turned, the fasterthe magnet will spin, resulting in an alternating voltage and current that switches directionsmore often in a given amount of DC generators work on the same general principle of electromagnetic induction, theirconstruction is not as simple as their AC counterparts. Witha DC generator, the coil of wireis mounted in the shaft where the magnet is on the AC alternator, and electrical connectionsare made to this spinning coil via stationary carbon brushes contacting copper strips on therotating shaft.