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How to contribute to this book

As a copylefted work, this book is open to revision and expansion by any interested parties. The only “catch” is that credit must be given where credit is due. This is a copyrighted work: it is not in the public domain!

If you wish to cite portions of this book in a work of your own, you must follow the same guidelines as for any other copyrighted work. Here is a sample from the Design Science License:

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because the Work comes WITHOUT ANY WARRANTY -- see Section 7 (“NO    
WARRANTY”) below.                                               

If you wish to modify this book in any way, you must document the nature of those modifications in the “Credits” section along with your name, and ideally, information concerning how you may be contacted. Again, the Design Science License:

Permission is granted to modify or sample from a copy of the Work,    
producing a derivative work, and to distribute the derivative work    
under the terms described in the section for distribution above,      
provided that the following terms are met:                            
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       the Work, in any way.                                          
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Given the complexities and security issues surrounding the maintenance of files comprising this book, it is recommended that you submit any revisions or expansions to the original author (Tony R. Kuphaldt). You are, of course, welcome to modify this book directly by editing your own personal copy, but we would all stand to benefit from your contributions if your ideas were incorporated into the online “master copy” where all the world can see it.


All entries arranged in alphabetical order of surname. Major contributions are listed by individual name with some detail on the nature of the contribution(s), date, contact info, etc. Minor contributions (typo corrections, etc.) are listed by name only for reasons of brevity. Please understand that when I classify a contribution as “minor,” it is in no way inferior to the effort or value of a “major” contribution, just smaller in the sense of less text changed. Any and all contributions are gratefully accepted. I am indebted to all those who have given freely of their own knowledge, time, and resources to make this a better book!

Tony R. Kuphaldt

  • Date(s) of contribution(s): 1996 to present
  • Nature of contribution: Original author.
  • Contact at: liec0@lycos.com

Jason Starck

  • Date(s) of contribution(s): May-June 2000
  • Nature of contribution: HTML formatting, some error corrections.
  • Contact at: jstarck@yhslug.tux.org

Dennis Crunkilton

  • Date(s) of contribution(s): April 2005 to present
  • Nature of contribution: Spice-Nutmeg plots, gnuplot Fourier plots chapters 6, 7, 8, 9, 10; 04/2005.
  • Nature of contribution: Broke “Special transformers and applications” section into subsections. Scott-T and LVDT subsections inserted, added to Air core transformers subsections chapter 9; 09/2005.
  • Nature of contribution: Chapter 13: AC motors; 01/2006.
  • Nature of contribution: Mini table of contents, all chapters except appedicies; html, latex, ps, pdf; See Devel/tutorial.html; 01/2006.
  • Nature of contribution: Chapters: all; Incremented edition number to 6 for major format change. Added floating captioned LaTeX figures for more book-like appearance of .pdf; 06/2006. Added Doubly-Fed Induction Generator subsection, CH 13.
  • Nature of contribution: Chapter 13: AC motors,“Running 3-phase motors on 1-phase”, added to. Ch10, Ch12, minor change, 02/2009.
  • Contact at: dcrunkilton(at)att(dot)net

Bill Stoddard, www.billsclockworks.com

  • Date(s) of contribution(s): June 2005
  • Nature of contribution: Granted permission to reprint synchronous westclox motor jpg's, Reprinted by permission of Westclox History at www.clockHistory.com, chapter 13
  • Contact at: bill(at)billsclockworks(dot)com

Your name here

  • Date(s) of contribution(s): Month and year of contribution
  • Nature of contribution: Insert text here, describing how you contributed to the book.
  • Contact at: my_email@provider.net

Typo corrections and other “minor” contributions

  • line-allaboutcircuits.com (June 2005) Typographical error correction in Volumes 1,2,3,5, various chapters, (s/visa-versa/vice versa/).
  • The students of Bellingham Technical College's Instrumentation program.
  • Bart Anderson (January 2004) Corrected conceptual and safety errors regarding Tesla coils.
  • Ed Beroset (May 2002) Suggested better ways to illustrate the meaning of the prefix “poly-” in chapter 10.
  • anonymous (September 2007) Typo correction in Basic AC chapter, s/Alterantor/Alternator.
  • Michiel van Bolhuis (April 2007), Corrections numerous chapters, images: 12008.eps, 02053.eps, 02056.eps, 02062.eps, 02515.eps, 02257.eps, 02258.eps, 02068.eps, 02074.eps, 02516.eps, 02516.eps, 02263.eps, text: s/(Figure 8.18/(Figure 8.18), s/dividing it my the/dividing it by the/, s/will be drive it/will drive it/, s/because we can to use/because we can use/, s/phase shift makes complicates/phase shift complicates/, s/750 kiloWatt/750 Watt, s/over 50 Kw use/over 50 kW use/, s/in an open ended/in open ended/.
  • Kieran Clancy (August 2006) Ch 4, s/capcitive/capacitive, s/positive negative/positive or negative.
  • Richard Cooper (December 2005) Clarification of 02206.eps, 02209.eps 3-phase transformer images. Correction of 02210.eps open-delta image.
  • Colin Creitz (May 2007) Chapters: several, s/it's/its.
  • Duane Damiano (February 2003) Pointed out magnetic polarity error in DC generator illustration.
  • Jeff DeFreitas (March 2006)Improve appearance: replace "/" and ”/" various chapters.
  • Sean Donner (January 2005) Typographical error correction in “Series resistor-inductor circuits” section, Chapter 3: REACTANCE AND IMPEDANCE -- INDUCTIVE “Voltage and current” section, (If we were restrict ourselves /If we were to restrict ourselves), (Across voltage across the resistor/ Voltage across the resistor); More on the “skin effect” section, (corrected for the skin effect/corrected for the skin effect).

    (January 2005),Typographical error correction in “AC capacitor circuits” section, Chapter 4: REACTANCE AND IMPEDANCE -- CAPACITIVE (calculate the phase angle of the inductor's reactive opposition / calculate the phase angle of the capacitor's reactive opposition).

    (January 2005),Typographical error correction in “ Parallel R, L, and C” section, Chapter 5: REACTANCE AND IMPEDANCE -- R, L, AND C, (02083.eps, change Vic to Vir above resistor in image)

    (January 2005),Typographical error correction in “Other waveshapes” section, Chapter 7: MIXED-FREQUENCY AC SIGNALS, (which only allow passage current in one direction./ which only allow the passage of current in one direction.)

    (January 2005),Typographical error correction in “What is a filter?” section, Chapter 8: FILTERS, (from others in within mixed-frequency signals. / from others within mixed-frequency signals.), (dropping most of the voltage gets across series resistor / dropping most of the voltage across series resistor)
  • Brendan Finley (March 2007) Suggested content change in Transformers chapter, clarified text, changed image 02305.eps “Mutual inductance and basic operation” section.
  • Steven Jones (November 2006) Suggested content addition in Power factor chapter, added graph to “Calculating factor correction” section.
  • Harvey Lew (February 2003) Typo correction in Basic AC chapter: word “circuit” should have been “circle”.
  • Elmo Mäntynen (August 2006) Numerous corrections in chapters: Resonance, Polyphase AC Circuits, Power Factor, AC Motors.
  • Jim Palmer (May 2002) Typo correction on complex number math.
  • Bob Schmid (April 20027) Suggested we add Inductosyn, added to Ch12“AC metering”.
  • Don Stalkowski (June 2002) Technical help with PostScript-to-PDF file format conversion.
  • John Symonds (March 2002) Suggested an improved explanation of the unit “Hertz.”
  • Puddy Tat@allaboutcircuits.com (May 2007) Pointed out error in Form Factor definition and calculation, 3plcs Ch 1.3 .
  • Joseph Teichman (June 2002) Suggestion and technical help regarding use of PNG images instead of JPEG.
  • Mark D. Zarella (April 2002) Suggested an improved explanation for the “average” value of a waveform.
  • machan@allaboutcircuits.com (April 2007) Transformer voltage regulation example error, image: 12105.eps.
  • recca02@allaboutcircuits.com (April 2007) Resonance, Parallel; missing formula, image: 12081.eps.
  • earsintraining@allaboutcircuits.com (July 2007) Ch 1, “AC Phase” image 02022.png not displayed in html.
  • Dave@allaboutcircuits.com (Aug 2007) Ch , s/Vary/Very/ .
  • jut@allaboutcircuits.com (Sept 2007) Ch 1 , s/as a the/as the/, s/eight white/seven white/ .
  • rrgibbs@allaboutcircuits.com (Oct 2007) Ch 1 , s/100/180 trigonometric sin function table.
  • Devin Bayer (September 2007) Correction to sml2html.sed, } to } in <tabular>.
  • mike@allaboutcircuits.com (Nov 2007) Ch 13 , Corrected error concerning Tesla's sale of AC induction motor, Change one million to to $65,000.
  • stacymckenna@allaboutcircuits.com (Feb 2008) Ch 9 , Clarification of light load as refering to less current.
  • Unregistered@allaboutcircuits.com (Feb 2008) Ch 2, s/by/be in "More on AC polaity" section.
  • Timothy Kingman (Feb 2008) Changed default roman font to newcent.
  • Imranullah Syed (Feb 2008) Suggested centering of uncaptioned schematics.
  • ShaunManners@allaboutcircuits.com (Feb 2008) Ch 1 , Error in the sign of value in sine table.
  • Dennis Crunkilton (Feb 2009) Ch 13 , s/Over-speed/Under-speed 02514.png
  • peter o@allaboutcircuits.com (Feb 2009) Ch 2 , image 02046.png
  • Unregistered Guest@allaboutcircuits.com (April 2009) Ch 2 , s/that its/that it is/.
  • The Electrician@allaboutcircuits.com (November 2009) Ch 1, Clarification: average responding metermovement is a d'Arsonval movement.
  • whanes@allaboutcircuits.com (January 2010) Ch 13, image 02419.png 02420.png moved single phase motors for polyphase to singnle phase tree.