Talk:Electrical impedance/Archive 3

Merger proposal
It is proposed to merge Impedance of different devices (derivations) into this article. The article says little or nothing that is not already said here and said better and in places is just plain wrong. Besides which it is practically orphaned.  Sp in ni ng  Spark  18:42, 14 June 2008 (UTC)


 * I have created a version of this article including the derivations at User:DJIndica/Sandbox2. I'd appreciate any comments.--DJIndica (talk) 12:29, 18 July 2008 (UTC)

Question
Vp stands for peak voltage, right? I'm referring to the part about capacitors in the Device Examples section of the article. If not please explicitly state what Vp is, since I don't think it is something that can be easily inferred from the article. 96.60.80.133 (talk) 03:09, 13 November 2008 (UTC)

I would also like to add that I found this article very helpful. From reading some of the discussion here I understand that some of you guys are extremely intelligent and I thank you for all your contributions. 96.60.80.133 (talk) 03:38, 13 November 2008 (UTC)


 * Vp is the voltage amplitude, which is indeed the peak voltage given that there is no DC offset.--DJIndica (talk) 19:01, 13 November 2008 (UTC)

Collapsable tables
The collapsable tables that were hiding the device specific derivations didn't expand when the printable version was selected, so a printout made from the page would be missing fairly useful information. I removed the tables and made the table headings into subsubsections. --Autopilot (talk) 17:02, 19 January 2009 (UTC)

SVG characters look poor
Several of the SVG images on this page are rendering fonts much larger than they should be. That is, I don't think they're properly scaling with the image. For example,
 * [[Image:Impedance_symbol_comparison.svg|100px]]

looks fine when you click on it, but in its scaled version here and on Electrical impedance, the $$Z_S$$ and $$Z_L$$ in the bottom two images are HUGE. Do other people see this? &mdash;TedPavlic (talk) 16:24, 28 January 2009 (UTC)
 * On the bottom image, yes. On the middle image, only for Zs, not ZL. That's in Firefox 3.05. Got the same result in IE6.  I'll try downloading the SVG and see what I can see in the editor.  Sp in ni  ng  Spark  10:36, 29 January 2009 (UTC)


 * I have fixed the problem, not really sure what it was but I fixed it by cut-and-paste of the good parts of the image. It is showing correctly on the thumbnail in Commons, but I don't seem to be able to get Wikipedia to purge the old version by any of the usual methods.  It is definitely fixed though, if I upload the image directly to the Wikipedia sandbox, I get this;
 * 
 *  Sp in ni ng  Spark  11:17, 29 January 2009 (UTC)
 * Thanks. After your changes, "hard refreshing" (i.e., forcing the browser to refresh the cache) fixes the problems. I suspect "Shift+Refreshing" on your end will fix cause your new version to show. &mdash;TedPavlic (talk) 13:59, 29 January 2009 (UTC)

Poor readability of text with Greek and generated images
The text looks ugly in Internet Explorer 8 where LaTex-generated expressions and even Greek symbols are rendered into IMG elements with vertical alignment that is incorrect and fonts that are of poor quality.

Is there a reason why we should not simply use Unicode characters as per web standards and use sup and sub elements for simple inline definitions of symbols and short simple inline expressions?

I'm aware that extremely old web-browsers have problems with some Unicode characters. (IE5/win for example). But if wikipedia's engine needs to take special measures to help such old browsers then so be it, surely it's time to stop de-optimizing everything because of the limitations of the most broken software. I'd be grateful if someone would give some pointers to what I imagine may be long-established reasoning behind the design decisions in this area.CecilWard (talk) 17:32, 7 June 2009 (UTC)


 * The relevant guideline is Manual of Style (mathematics). There is no rule against using HTML markup for formulae instead of LaTeX, however, some things can only sensibly be typeset in LaTeX, and in my view it looks an inconsistent mess to have a mixture of the two in the same article.  I think the point you raise is not really a matter for (just) this article.  Wikipedia wide issues are discussed at the village pump.  Sp in ni  ng  Spark  00:19, 8 June 2009 (UTC)


 * I have changed the inline LaTeX to "scriptstyle" which will render in a smaller font more compatible with the text and getting a better vertical alignment - but still not perfect. It looks acceptable to me in both Firefox 3 and IE6, don't know about IE8.  Sp in ni  ng  Spark  01:05, 8 June 2009 (UTC)

Modifications to lead
The reason I made this change was because I was unhappy with the phrase "never as a function of time"; whilst it's true that impedance expresses the ratio of a phasor at a given frequency, it's simply not the case that it can *never* vary with time.
 * You misunderstand the definition of impedance and the use of complex exponentials in the solutions of LTI systems. It's true that the voltage–current relationship can vary over time in such a way that can be approximated like a system with a time-varying impedance, but the concept of impedance cannot ever be extended to the time-varying case. &mdash;TedPavlic (talk/contrib/@) 12:42, 6 August 2009 (UTC)
 * Oh, I understand perfectly well the implications of the Fourier transform (that the integral is over all time); from a mathematical point of view, Z(f) is the voltage/current ratio of a phasor of infinite length. However, in practice, we never deal with things that last forever.  So in practice, we may well see an "impedance" that vary over time, and that to all practical intents and purposes acts exactly like a "formal" impedance derived from the Fourier transform over all time of a true LTI system.  The level of detail required to explain this dichotomy is overwhelming for the lead.  Oli Filth(talk&#124;contribs) 14:01, 6 August 2009 (UTC)


 * Again, I think you misunderstand. Impedance is a concept defined for infinite time horizon signals, and the finite time horizon signals are limits of convergent series of infinite time horizon signals. These additional components become very important when designing, say, pulsed RADAR systems. Likewise, if you pulsed a laser fast enough and passed it through a prism, the light would start to spread into different colors (even though the laser was "originally" a "single" color). Filters act on the terms of these series, and thus you get different finite-time signals. So it's entirely appropriate to discuss the infinite-time horizon properties. &mdash;TedPavlic (talk/contrib/@) 14:44, 6 August 2009 (UTC)

When I mentioned varactors/varicaps in my edit summary, I was not referring to small-signal non-linearity, instead I was alluding to the fact that system parameters may vary over time (varactors happen to be an example where the small-signal parameters are actively controlled).
 * Again, I think you misunderstand. The small-signal parameters are linear, but the small-signal model is just an approximation of reality. The reality is the "large signal" model. Over large signal swings, a varicap does not have a linear impedance regardless of its bias. Over small signal changes, the bias effect dominates; however, the voltage–current ratio still is not that linear. In fact, the difference between a varicap and a diode is that a varicap has been specially designed to have an excessively large linear approximation region. &mdash;TedPavlic (talk/contrib/@) 12:42, 6 August 2009 (UTC)


 * Again, I'm aware of that, and again I was merely trying to highlight that in many practical situations, the time-varying linear small-signal model is a perfectly valid approximation. Oli Filth(talk&#124;contribs) 14:01, 6 August 2009 (UTC)


 * I'm not saying that small-signal linearization is invalid. I'm saying that within the small-signal model, the impedance does not change over time. When you ramp the bias, it's inappropriate to think of the small-signal model having a time-varying impedance. Instead, a ramping bias shifts you from one small-signal model to another. Additionally, you're not factoring in any of the transient effects that die out when moving from one bias point to the other. Saying that you can have a "time varying impedance" implies that you can do LTI-like things to systems that are time varying. &mdash;TedPavlic (talk/contrib/@) 14:44, 6 August 2009 (UTC)

I believe the latest changes has now somewhat overcomplicated the issue, and consequently the last three sentences should be removed (or at the very least, moved from the lead, as it shouldn't contain material that isn't discussed elsewhere in the article). Oli Filth(talk&#124;contribs) 19:46, 5 August 2009 (UTC)
 * Done. &mdash;TedPavlic (talk/contrib/@) 12:42, 6 August 2009 (UTC)


 * Thanks! I've reworded the new section slightly to avoid "infinite-time-horizon" and the specific varicap example, please let me know if you object.  Oli Filth(talk&#124;contribs) 14:01, 6 August 2009 (UTC)


 * I'd like to put the varicap in as an e.g. Otherwise, if the present wording is better for you, it's better for some other people out there too, and so it's fine. &mdash;TedPavlic (talk/contrib/@) 14:44, 6 August 2009 (UTC)

Generalise
I moved the lead to a new paragraph and tried to write a short lead on the general topic of impedance seeing as the old one only covered ac theory. Unfortunately I dont have the time to do it properly, and I understand that it will recquire extensive further modification and hope someone else can offer the time recquired. Thanks. —Preceding unsigned comment added by 129.67.119.67 (talk) 18:13, 28 February 2010 (UTC)
 * I was only trying to help. But obv this man thinks that (most likely because I am an IP) my contributions are unworthy.  —Preceding unsigned comment added by 129.67.116.170 (talk) 17:06, 2 March 2010 (UTC)


 * I have to agree with the reversion, especially as this was a complete change to the lede, although the edit summary is a little bitey. The title of the article is "Electrical impedance", not "impedance of the medium" which is a completely different thing.  In future, you might want to consider trailing such major revisions on the article talk page first.  We already have impedance of free space which is the concept you are talking about, but there does not seem to be an article extending this idea to other mediums.  You might want to think about starting a new article!  Sp in ni  ng  Spark  16:40, 4 April 2010 (UTC)
 * Actually, just discovered we do have an article already, wave impedance.  Sp in ni ng  Spark  20:36, 4 April 2010 (UTC)

Simplify??
I would like to suggest that this article is unnecessarily difficult to read and understand, excessively mathematical, inappropriately theoretical and useless in understanding higher voltage applications. Impedance can be understood as the collective effect of resistance, inductive reactance and capacitative reactance. Changes in voltage and load can be viewed with an appropriately configured oscilloscope. When the two sine waves are 45 degrees out of phase, power is reduced because (using Ohm's Law every time either line crosses zero the power drops to zero Watts. Power lines become clogged with VARS (volt-amps reactive), rather than Watts, reducing system capacity. Since inductive reactance is the more common problem, utility companies typically install banks of large capacitors to balance out inductive reactance with a calculated mount of capacitative reactance. There should be a photo of a capacitor bank. These can be seen atop power poles all over the place. School children can learn to recognize them. Once this has all been established at the visible, practical real-world macro level, the article could refocus on the itty-bitty circuits and theory. This, by the way, represents a common problem with technical Wikipedia articles -- they get too theoretical, academic and technical to be of use to the average encyclopedia user. 97.90.105.186 (talk) 05:37, 2 June 2010 (UTC)


 * My guess is that this article is theoretical because it's describing the underlying theory of impedance, which is fundamentally an abstract mathematical construct. The example you give (power-factor correction) is one specific, qualitative application.  This is described in the Power factor article, which in my opinion is the correct location.


 * Perhaps we should find a way to work appropriate links into this article, but we shouldn't be going into great detail. Oli Filth(talk&#124;contribs) 18:16, 2 June 2010 (UTC)


 * I have to agree. I think it is terrible that electric effective resistance (http://en.wikipedia.org/wiki/Electric_effective_resistance) is redirected here.  I came here looking for the standard definition for a network of resistors with a source and sink (DC current), and it is a mistake that the only article is in unnecessary generality.  It is basically unreadable.  (I say this because effective electrical resistance is a concept that has purely mathematical applications, for which electricity is just a metaphor, and AC current is meaningless.  Also, I think that most hobbyists playing with electrical circuits use DC current only.)  — Preceding unsigned comment added by 71.139.164.223 (talk) 21:46, 21 December 2011 (UTC)

Generalised s-plane impedance
The recently added content on s-domain impedance is problematic, IMO.

First, as far as I know, the notion that, for example, an inductor presents an impedance to, for example, a square wave source is incoherent. Rather, an inductor presents an impedance to each component of the square wave. The added section suggests that the impedance of an inductor for an arbitrary periodic signal is the sum of impedances to the individual components. Summing these impedances makes no sense at all. What would one do with this number? What current would one multiply this impedance by to get what voltage?

Second, it's unclear what the statement "Non-periodic signals will have a real part to s." means in this context. According the chart above it, the s-domain impedance of an inductor is sL. In this context, the 's' is the complex coefficient of t in the complex exponential excitation, A exp{st}. For example, v(t) = sL i(t) where i(t) = I exp{st}. That's the context of s-plane impedance.

However, the statement in question appears to be in the context of the parameter s in the Laplace transform of a signal and that's a different 's' altogether. Consider the Laplace transform of the unit step, a non-periodic function. According the statement above, there is real part to s. What is the real part of s for the unit step? And what does that real part have to do with s-plane impedance? Alfred Centauri (talk) 02:06, 12 July 2010 (UTC)

Definition of Impedance
Currently, the article states Impedance is defined as the frequency domain ratio of the voltage to the current. I've added a citation request. I've been taught that impedance is the ratio of the voltage and current phasors. Although phasors are related to the frequency domain, the definitions are not identical. Here's a cite from "Standard Handbook for Electrical Engineers", 13 edition:


 * An impedance of a linear constant-parameter system is the ratio of the phasor equivalent of a steady-state sine-wave voltage or voltage-like quantity (driving force) to the phasor equivalent of a steady-state sine-wave current or current-like quantity (response).

Alfred Centauri (talk) 13:11, 14 July 2010 (UTC)

The phase shift (leading or lagging terms)
Um, the opening paragraph has 1 of its primary points wrong. The phase shift or angle of impedance describes how much the Voltage leads the current, not the other way around. In a capacitor, the phenomenon has to do with voltage, so the current leads the voltage, which is why it X_c lies on the -j axis. In the correct picture, voltage leads current by -90 degrees, or voltage lags current by 90 degrees. This is exactly the opposite of what this article has written. 166.19.102.20 (talk) 14:48, 25 August 2010 (UTC)

Untitled post
I suggest instead of "the impedance of inductors increases with frequency" in paragraph "device exemple" to wright "the impedance of capacitors increases with frequency"

wright  — Preceding unsigned comment added by 93.46.208.51 (talk) 13:54, 2 September 2011 (UTC)


 * Wrong!  Spinning Spark  15:33, 2 September 2011 (UTC)


 * Note to the original poster, when the frequency is low, the impedance of the capacitor is high, so most current will flow through the resistor. As the frequency increases, more current is diverted through the capacitor, less to the rest of the circuit. Thus, the response is low pass. If you exchanged the capacitor and resistor, you'd have a high pass circuit. Please see, http://artsites.ucsc.edu/EMS/Music/tech_background/Z/impedance.html Sunshine Warrior04 (talk) 08:28, 26 October 2011 (UTC)

Wrong definition?
I think the definition of impedance given in the lead section "Electrical impedance, or simply impedance, describes a measure of opposition to alternating current (AC)" is wrong. Impedance = reactance + resistance (as is correctly stated later in the article) so an impedance which includes resistance would oppose DC as well as AC. Biscuittin (talk) 18:53, 20 October 2011 (UTC)


 * I would humbly call attention to several definitions quoted from good sources here: http://www.answers.com/topic/electrical-impedance


 * Perhaps someone can use one of these definitions and quote the source. If no one else chooses to do so than I can. Sunshine Warrior04 (talk) 08:02, 26 October 2011 (UTC)


 * I have partly reverted this; to say only that "it is the complex ratio of the voltage to the current" is only meaningful to someone who (a) understands what a complex ratio means, and (b) is already familiar with the concept of impedance. The lede paragraph needs to spell out what is different about impedance - that is its possession of phase - and that it only differs from resistance in an AC circuit.  I have also added a paragraph stating the causes of impedance as the second para of the lede which I think may be a key thing a casual reader may be looking for.


 * I have also removed the citation. It really will not do to have answers.com as a reference, especially as it gives the Wikipedia article as one of the answers making it circular.  Spinning  Spark  18:38, 26 October 2011 (UTC)


 * I understand completely. Its interesting how Wikipedia is now being quoted as a source when it should not. When I was in school I was specifically told not to use Wikis as information sources. Guess some people tend to get lazy. Sunshine Warrior04 (talk) 22:02, 26 October 2011 (UTC)

Comments and questions
1. Why should the text for Z, X, V, I be so small?

2. What is "DIN Euro"?

It would be nice to explain and possibly provide a link.

3. The last two expressions in the "Complex voltage and current" section coexist and should really be represented as a system of equations.

4. The "Phasors" section deserves to be improved by the addition of a few expressions like the previous sections.

5. The statement "The total reactance is given by X=XL-XC" is somewhat ambiguous and general. I think the sentence should be "The total reactance of an inductive and capacitive circuit is given by X=XL-XC".

6. "Estimating the frequency response of a dynamic system such is the impedance requires measuring the impedance response to an input signal excitation in the form of an impulse function, sweeping the frequency of a sine wave excitation in the bandwidth of interest, or applying a spread-spectrum signal generated with a particular bandwidth."

Something is wrong with this sentence.

ICE77 (talk) 23:15, 3 November 2015 (UTC)

Latest contribution
I've undo the undo of Spinningspark. I'm not against removing/modifying some parts of the latest contribution, but it is rather ridiculous to undo all this contribution at once, using so superficial and inexact justifications. So, let us begin from the beginning:
 * If there is a notion of impedance for multiport (that is, something that is really CALLED impedance by serious authors), could you please provide your sources? In this case, I will simply warn the reader that such a notion has been extended to multiport. It is nevertheless important for the clarity of the exposition to tell the reader what is the most USUAL notion of impedance. EDIT: I've modified the disputed sentence and taken into account the remark of Spinningspark (see the article). So, there may remain no disagreement.
 * It is absolutely unlogical to expose "Ohm's law" before "complex voltage and current". Again, give justification for opposing to this change.
 * Regarding your remark "Giving alternative derivations unnecessarily overcomplicates this article and is all a bit WP:NOTTEXTBOOK." This is subjective and strongly disputable. The given derivations are not unnecessary: it is unclear why the article sometimes assumes a given AC sinusoidal voltage, and sometimes a given AC sinusoidal current. It is important to point out that this leads to the same results. This contributes to the clarity of the article too.
 * Finally, give justifications please why you have removed the section "Determination of the resonance by the method of complex impedances".       maimonid (talk) 19:36, 17 June 2017 (UTC)

Answer:
 * First, please use terminal or terminals in place of pole and poles, because poles have many different meanings.
 * With regard to your other points
 * The elements of an impedance matrix are called impedances. This is common knowledge and will appear in any text book that discusses two-ports or multiports.
 * I can see some logic in discussing complex current and voltage before ohms law. I think that this merits some discussion.
 * I haven’t had time to look at your alternate derivations, so I have no opinion on them at this time.
 * The section on resonance does not belong in an article about impedance. Besides, it is a discussion  that focuses on a single idealized, non-existent combination of two ideal components.  If you have ever done a frequency sweep of a real LC circuit you will find multiple resonances and anti-resonances. Constant314 (talk) 20:33, 17 June 2017 (UTC)

Answer:
 * "Terminal" refers to the physical connections of a circuit, while "pole" refers to the schematics or abstract connections: this is not my definition, but the definition of Wikipedia in another article. Regarding your other remarks:


 * Of course, because the elements $$Z_{i,j}$$ of an impedance matrix are just the impedance between pole i and pole j.
 * The section on resonance is not about resonance, but how the impedance relates to resonance. Contrarily to your opinion, the method is quite general and not reduced to two ideal components: it applies to any combination of R, L and C components (if you wish, I can change the example given in the article and replace it with a RLC tank circuit). Moreover, I think you are confusing the notion of resonance with that of harmonics. EDIT: I've replaced the content of this section by a more general, concise and comprehensive exposition.maimonid (talk) 21:38, 17 June 2017 (UTC)
 * You are entirely wrong that the elements of an impedance matrix are the impedances between poles. See the transimpedance and impedance parameters articles if you are cofused about this.
 * The relationship between resonance and impedance becomes ever more complex with increasing number of elements. Resonance does not directly relate to impedance minima for anything but the most simple networks.  In fact, the definition of resonance becomes problematic in complex cases.  Of course, if one defines resonance as impedance minima then you are merely stating a truism, but that is not the only way of defining it.  I defy you to find an impedance minima in a Butterworth crossover filter.  There are none, the driving point impedance is constant, but there are still resonances going on.  It is more usual, and more productive, in complex passive circuits to talk about poles and zeroes.
 * You requested that I provide sources for my objections, but you have provided absolutely none for your contributions. It is for you to provide sources, please do so, otherwise I will propose that your additions are removed in their entirety.
 * I request that you stop editing the article for the time being. It is very difficult to hold a discussion on material that is constantly changing. SpinningSpark 15:53, 18 June 2017 (UTC)

Answer:
 * >>"I request that you stop editing etc" - agreed. I point out that the only part I have continuously edited is the new section of my own about resonnance, to take into account your remarks and those of Const314 and to reach, hopefully, a consensus.
 * Because of some lack of attention, I've indeed confused something in my answer to Const314 regarding the definition of the parameters of the impedance matrix, but this changes nothing to the pertinence of the answer: first of all, the parameters are called trans-impedance parameters and not "impedance parameters" as claimed by Const314. And second, the diagonal terms (which are indeed impedances) ultimately relate to two poles, namely the poles of the ports. finally, your objection is somewhat paradoxical, after the article itself defines the impedance as the ratio of the complex voltage by the complex current.
 * Most usually, the term resonance is used in the context of systems with one degree of freedom, and this could be made explicit in the article if you wish. Even though I would not be surprised that some authors use the terms "multiple resonance" for systems with several degrees of freedom, terms like "modes", "fundamental frequency" and "harmonics" are more usual. Whenever an oscillating electrical system with one degree of freedom is excited at two poles A and B, the response to the excitation is maximal at the resonance frequency. This exactly means that the ratio of the excitation voltage with the excitation current is maximal. As far as I know, a filter is not a self oscillating system, unless perhaps, you connect its two poles one to the other, which is probably not what you meant. Looking at your answer, I found it rather unclear or even sophistical; it feels like you put your honour in removing this section, so let's do it. I will not oppose if you remove this section, but I left this task for you or someone else.
 * >>"You requested that I provide sources for my objections", indeed, regarding a specific point and in order to obtain a consensus. You have first brutally undo my whole contribution without even trying to understand it, or at least to try to discuss it in the talk page. This is not the right Wikipedia way (see your own links). Usually, one tries to improve the new contributions to make them eventually more precise and conform to the Wikipedia recommendations. I've continuously tried to take into account your remarks and those of Const314. On the contrary, you "defy" me, you "request" I provide source for everything I wrote despite this is common knowledge etc. Please, consider I am not your enemy in any way but an honest contributor, and try to reach honestly a consensus with me. maimonid (talk) 18:49, 18 June 2017 (UTC)
 * Please read Verifiability, one of our core content policies: "Any material lacking a reliable source directly supporting it may be removed and should not be restored without an inline citation to a reliable source." SpinningSpark 19:57, 18 June 2017 (UTC)
 * Thank you for the link and the other links, but I wish to inform you that I am not a newbie in Wikipedia: I am an old contributor, that already knows the main policies. So, in the future, you may want to refrain from educating me. I understand from the form of your answer that you have nothing more to object, so can we consider that a consensus has been obtained? I remains at your disposal if you want to discuss about a SPECIFIC point. Because I suppose you understand it would be an act of vandalism to remove the whole contribution without pointing to anything specific.maimonid (talk) 20:36, 18 June 2017 (UTC)
 * No, you can't assume consensus. Your writing on resonance is inaccurate and off-topic for this article.  Yes, student textbooks study first and second order circuits in detail, but that is just the nature of textbooks, it does not mean that that is all there is to it.  If you are really the experienced user you claim, you should know better than to accuse good faith editors of vandalism. And if you are as familiar with WP:V as you claim, you would know that challeged material must be cited or risk removal. SpinningSpark 21:30, 18 June 2017 (UTC)
 * I don't understand what is the problem: I've already agreed this section be removed (I hope you've read my answer above). Contrarily to your opinion, this section may need some small improvements, but it is correct (you most probably know this important principle of Wikipedia: "When you find a passage in an article that is biased or inaccurate, improve it if you can; don't delete salvageable text"). I've not accused you or anyone else of vandalism, that is, not yet. In fact, I does believe you were of good faith when you undo-ed all my contribution the first time: even though I think these methods are brutal and inappropriate to Wikipedia, I'm aware that it is not always easy for a buzzy administrator to protect articles from vandals, newbies etc. This is why you should not feel hurt in any way that I've undo-ed your first undo. Regarding the resonance section, as I said, it is not so important for me after all and can be removed. I may rewrite later a more complete and well sourced section about this topic in some article about electrical resonance. maimonid (talk) —Preceding undated comment added 22:05, 18 June 2017 (UTC)
 * Ok, taking you at your word, I have removed the section. There were numerous problems with it.  There are many circuits for which differentiating the driving point impedance will fail to find a point of resonance, or even any extrema at all.  I gave one well known example above.  Other simple examples are this circuit and this one.  Both clearly have resonances going on, but they are hidden from the external circuit.  You define resonance as minimum current, but a series resonant circuit will pass maximum current at resonance.  It is only parallel resonance in which the current is minimised.  Some authors would call this latter case antiresonance.  Minimum (or maximum) impedance is not the only way of defining resonance.  In some contexts, the driving point impedance becoming purely real is used.  For simple, lossless, 2-element circuits this gets the same result, but even this simple RLC circuit gives different values for the two definitions.  In short, there is no simple straightforward relationship between resonance and impedance in general.  The section added is both WP:OR and off topic.  One other thing, I don't know why you have brought up my administrator status, but let me make this clear; I am not acting here as an administrator.  Rather, I am acting as an ordinary editor who has some interest in, and knowledge of, this subject. SpinningSpark</b> 15:38, 19 June 2017 (UTC)

Impedance matrix
I think the claim that " In circuits with two or more ports, the impedance matrix or transfer function between the input and output ports may be used" is also problematic in a number of ways. Not least because it is in the lead and there is nothing further in the body of the article. The linked article is no help at all. Impedance parameters would be a better link, but I am wondering if this is going off at another tangent making this article more complicated and difficult than it needs to be. It is also the case that the open-circuit parameters (as used in the z parameters) are not the only way of measuring the port impedances of a multi-port. See for instance scattering parameters, admittance parameters, image impedance, and iterative impedance. The only essential point here is that to measure a port impedance of a multi-port, the terminations of the other ports must be defined. That is a simple point that does not require the matrix representation of networks to be invoked. <b style="background:#FAFAD2;color:#C08000">Spinning</b><b style="color:#4840A0">Spark</b> 16:02, 19 June 2017 (UTC)


 * >>"Not least because it is in the lead and there is nothing further in the body of the article." I think this sentence immediately clarify the situation, and as such, should be in the lead. The fact that there is nothing further in the body of the article is not unusual in Wikipedia. Anyway, I think the links I've added in the suggested sentence below solves this problem. Also, the suggested sentence takes into account your other remarks.
 * "Apart from basic facts, significant information should not appear in the lead if it is not covered in the remainder of the article" <b style="background:#FAFAD2;color:#C08000">Spinning</b><b style="color:#4840A0">Spark</b> 21:42, 19 June 2017 (UTC)
 * Spinnigspark, your are misinterpreting the term "significant information". This recommendation simply says that if you want to add serious content, don't do that in the lead but inside the article. On the contrary, about the lead: " It should identify the topic, establish context, etc".maimonid (talk) 05:54, 20 June 2017 (UTC)
 * >>"I am wondering if this is going off at another tangent making this article more complicated and difficult than it needs to be". Definitely not: this is an useful information of two lines that place the impedance concept in the real world, and connects this article with other articles. Beside, we are not especially writting for children or persons that are afraid to discover that there are things more complicated than Ohm law.
 * Following your observations, I suggest to replace the sentence:
 * "The concept of impedance is usually related to two poles circuits, that is, circuits where the current enters at one pole, and exits at the other pole. In circuits with two or more ports, the impedance matrix or the transfer function between the input and output ports may be used."
 * by:
 * "The concept of impedance is usually related to two poles circuits, that is, circuits where the current enters at one pole, and exits at the other pole. In circuits with two or more ports, several methods like the impedance matrix or the transfer function between the input and output ports may be used." (please, open the links)maimonid (talk) 21:22, 19 June 2017 (UTC)


 * Your last replacement of the disputed sentence is not only hardly understandable, but it is far too complicated for the lead. This is exactly what is called "significant content". We have to remain at the general level, and refrain from giving too elaborated information (especially because the information can be found by following the given links). I've replaced this sentence by another one, that, hopefully, will also be OK for you. N.B: I thought we agreed to refrain modifying the content of the article until a consensus has been reached.maimonid (talk) 07:45, 20 June 2017 (UTC)
 * There are numerous things wrong with that.
 * "Transfer function" is not a substitute for "impedance", there are all kinds of ways to define a transfer function. It is off-topic for this article.  Furthermore, transfer function only relates to single-input single-output systems.  In no way can a transfer function reperesent a two-port, let alone multi-ports.
 * For the record, here is the passage I replaced your text with and you reverted;
 * The only point that is relevant to this article is that the impedance matrix plays the same role in a matrix equation of a multiport as impedance plays in the constitutive equation of a one-port. Whatever faults my text has, at least it succeeds in making that central point which yours does not.
 * It is very bad practice to force the reader to follow a link to find out what 2-pole means when it can be glossed simply and easily in-article with the more familiar one-port. It says as much in MOS:LINKSTYLE.  It is also the case that the link you provided goes to the port article.  Far less confusing to link "port" directly.
 * I don't think we need to say that current enters one terminal and exits the other. The network has the property of impedance whether a current is flowing or not.
 * You have restored a grammar correction I made. We say "two-pole circut" in English, not "two-poles circuit".  If I am having to fight you with walls of text even over a simple grammar correction, then I am done discussing and will remove the passage altogether.  It is infuriating that you have reverted me with the argument that my contribution does not belong in the lead when I raised that same point over your original addition.  So I guess we both agree that it does not belong, but even if you don't, I am removing it as uncited and nothing should be restored until we have a source that actually supports what is said. <b style="background:#FAFAD2;color:#C08000">Spinning</b><b style="color:#4840A0">Spark</b> 21:43, 21 June 2017 (UTC)
 * I agree with Spinningspark; your addition was confusing, poorly worded ("pole" should be "port"), and not significant enough to appear in the introduction, even if there were a section in the article on 2-port impedance for it to refer to. - Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 22:01, 24 June 2017 (UTC)
 * As explained at the beginning of the discussion, the term pole is not "my" word, but a term actually used and defined in Wikipedia articles (see the cited article above, and use you browser to find the terms "two-pole"). I can conceive that this seems weird to most native English speakers, and I will take this into account in further contributions. But this is certainly part of the electrical engineering jargon. In fact, my impression is that this is high level jargon, but this should be confirmed.
 * Regarding your claim that the addition is not significant, have a look at the book "Electrical impedance, principles, measurement, and application", which dedicates its central chapters to the impedance matrix of multiple terminal networks. maimonid (talk) 20:40, 25 June 2017 (UTC)
 * Regarding your claim that the addition is not significant, have a look at the book "Electrical impedance, principles, measurement, and application", which dedicates its central chapters to the impedance matrix of multiple terminal networks. maimonid (talk) 20:40, 25 June 2017 (UTC)


 * >>"You have restored a grammar correction I made etc. I am having to fight you over a simple grammar correction etc."
 * Do you bother to stop inventing nonexistent facts and to fight me with your own inventions? I never "restored" a grammar correction, but a part of a whole sentence. This mistake simply occurred because of copy-pasting and multiple corrections. This is once more a ridiculous attempt to discredit me with an insignificant point. Moreover, you have used your lie to remove the whole passage.


 * >>"Port" is not a so familiar notion for most of the readers. I have already justified the term "pole" above and the difference with "terminal", and the term "two-pole" is actually used in the Wikipedia article cited above. But that's not the point and you know that: despite it is obviously part of the electrical engineering jargon, if it seems so weird to most native English speakers, I am not (and I was not) fundamentally opposed to replace it by "two-terminals".


 * >>"I don't think we need to say that current enters one terminal and exit the other. The network has the property of impedance whether a current is flowing or not." This is once more an insignificant point whose aim is only to block me: the meaning of the terms "that is, a circuit where the current enters at one terminal and exits at the other terminal" is clear for any person with an IQ equal (or less) to that of a monkey. I'm afraid that with such a ridiculous level of refinements, most of the matter in Wikipedia would be removed. A propo, I had a look at your contributions in other articles. You almost never contribute anything else to Wikipedia than removing vandalism or newbie contributions. That is your right and I should even admit that I agree with most of your undo-ing. But if you were contributing some concrete matter to Wikipedia, you would probably understand that a minimum of flexibility is necessary. It is far easier to remove passages using various pretexts, than to add something to the articles.
 * Thank you for the kind insult. You only have to look at my user page to discover that not only have I created many articles on Wikipedia, but I am also responsible for a string of Featured Articles and Good Articles.  Laughably, the article you insist on repeatedly referring my to, Port (circuit theory), was written by me.  I also wrote the better part of Network analysis (electrical circuits) which you also seem to think I need to read.  Have you managed to get any article at all through any kind of quality review here?  So which one of us knows how to write quality articles and which one is the monkey? <b style="background:#FAFAD2;color:#C08000">Spinning</b><b style="color:#4840A0">Spark</b> 21:43, 25 June 2017 (UTC)
 * Ok, so I was wrong to say that you contribute nothing but removing undesirable passages from Wikipedia. I apologize for that despite this is not so libelous (I tried to explain that some flexibility is needed). But I have nowhere insulted you: once more, you invent an nonexistent fact; the meaning of the sentence is absolutely clear: the readers have not the IQ of a monkey, so your remark is a useless refinement requirement. That's you that insult me at the end of your answer. maimonid (talk) 07:08, 26 June 2017 (UTC)


 * In my case, you are always welcome to correct grammar mistakes, to improve the style or even to remove obvious theoretical errors that I may mistakenly write. But in the future, I request you do not remove matter I write in this article or other ones, with such superficial or subjective justifications as "off topic": this is against the basic principles of Wikipedia that demand a discussion in the talk page. I am not the newbie or vandal you are familiar with, and I know perfectly what is off-topic and what is in-topic. In particular, a notion strongly connected to a subject is not off-topic, in particular if it is summed-up in one or two sentences. Actually, very often, readers seek in an article for a connection to related notions.


 * You found infuriating that I removed your (only) replacement of the disputed sentence, using your own argument. I am perfectly coherent with myself: I always says and believe that the lead should not contain unnecessary complicated content, and your mathematical explanation of the impedance matrix is more complicated than necessary, since it suffices to cite it and to connect it to the dedicated article. In my side, I found laughable that you replaced my sentence by yours after having invoked the principle of "no significant content in the lead".
 * In fact, what is truly infuriating (well I'm not furious), is that I've suggested a sentence in the talk page, and that you even not condescend to answer me or to propose something else in the talk page; instead, you introduced your own sentence in the article.


 * I will print and show your arguments in this discussion to my students, as an illustration of fallacious and sophistical arguments, as well as of blatant bad faith. Without exhausting the subject:
 * We agreed to abstain modifying the content of the article until a consensus has been reached, but this is exactly what you did;
 * You are not respecting the principles of Wikipedia, but you deliberately misinterpret them in order to use them to fight the persons who dare to disagree with your brutal removes and decisions;
 * You constantly use straw man arguments; I think this is so blatant that it is unnecessary I give examples; the last one was "transfer function is not a substitute for impedance". Indeed, and it was never claimed it is. But it is another tool that allows performing AC analysis of circuits. At the exception of the grammar mistake, what was wrong with the last sentences you removed? for memory:
 * "The concept of impedance is usually related to "two-pole" circuits, that is, circuits where the current enters at one terminal, and exits at the other terminal. Network AC analysis over multiple pole electrical networks can be carried out by means of more elaborated tools like the impedance matrix or the transfer function."


 * You use unclear pseudo-scientific or sophistical arguments to fight your opponent. For example the fact that the transfer function is related to input-output only systems. This is true as a general definition of time dependent signals. But in this case, the signals are the voltages at the poles: they are referenced to ground. The electrical circuit has actually 3 poles, the third being usually connected to ground. The most obvious example is a voltage divider, where you have V_in, V_out, and the third pole connected to the ground. See also this link.


 * Finally, when you have nothing serious to say, you unsheathe what you think to be the ultimate weapon: "do not resolve until cited". As I said previously, you do not really respect the principles, but you try to use them to fight your opponents. In this case, you even not specified about what you required a reference; the impedance matrix? - there is already an article about it and there are plenty of sources in Google. The transfer function - same remark. The fact that strictly speaking, impedance relates to two-pole circuits? This is not a new fact, but this is exactly what is written in the article: "it is the complex ratio of the voltage by the current", and this is the only manner to understand this definition. A clarification about a well accepted fact already written in the article needs no reference. This is the fact itself that needs a reference. But if only you had googled it, you would have found many sources that leave no doubt about this basic fact: for example: Impedance


 * I think I will stop here. There is nothing to do in such discussions and I am wasting my time. You won! You might well answer me, but in my side, I consider the debate is closed! maimonid (talk) 20:40, 25 June 2017 (UTC)

Deriving the device-specific impedances
Having given Maimonid quite a hard time over his contributions, I have to say that his alternative derivation makes a lot more sense and should be used to replace the original text. We currently have in the article;
 * $$\frac{v_{\text{C}} \left( t \right)}{i_{\text{C}} \left( t \right)} = \frac{V_p \sin(\omega t)}{\omega V_p C \cos \left( \omega t \right)}= \frac{\sin(\omega t)}{\omega C \sin \left( \omega t + \frac{\pi}{2}\right)}$$

Well that expression reduces to,
 * $$\frac{v_{\text{C}} \left( t \right)}{i_{\text{C}} \left( t \right)} = \frac{\tan(\omega t)}{\omega C}$$

In what way is that supposed to represent the impedance of a capacitor? By it's average value? It's RMS value? The first is zero and the latter is infinity. It is mathematical nonsense. Or at least very sloppy. <b style="background:#FAFAD2;color:#C08000">Spinning</b><b style="color:#4840A0">Spark</b> 12:42, 25 June 2017 (UTC)


 * I've spent some time to try to understand the editor thoughts, without success. I come to understand that the problem is even deeper: even though it may be possible to derive the complex impedance dealing with real voltages and currents only, using some interpretation, this is not the usual definition, and this is not coherent with the definition given in this article. Beside, I think this overcomplicates the matter. So, I agree with Spinnigspark. maimonid (talk) 18:16, 1 July 2017 (UTC)

Terminals vs poles
I have checked a few sources, including Standard Hanbdbook for Electrical Engineers by Fink and Beaty, the IEEE Standard Dictionary of Electrical and Electronics Terms, Engineering Circuit Analysis by Hayt and Kemmerly and the book recommended by Maimonid: Electrical impedance, principles, measurement, and application by Callegaro. All use the term terminals instead of poles. Callegaro, on page two, uses the term “two-terminal circuit element". Clearly, terminals is the commonly used language to designate the nodes of an impedance or a port.  So, please, let’s used the word terminal instead of pole as poles have other meanings, including the pole of a transfer function.  A complex impedance between two terminals could have poles and zeroes which would add to the confusion.  An impedance built from a network of Ls and Cs and Rs could be called a two pole impedance or three pole impedance or any number of poles impedance you can imagine.  Constant314 (talk) 23:18, 25 June 2017 (UTC)


 * Read my answer about this point above: I'm not opposed to this change; my aim is to write contributions that please to a maximum of readers, and these kind of remarks are particularly welcome for me. Note also that Callegaro uses the terms "two-terminal element" and "two-terminal network", but not "two-terminal circuit"; I'm not sure there is a good reason for that though. maimonid (talk) 06:54, 26 June 2017 (UTC)


 * "Two-pole circuit" replaced by "two-terminal circuit element" in the article. maimonid (talk) 09:09, 26 June 2017 (UTC)

About my last contribution to the article
The problem with the head was that it was too long and mixed too involved explanations. I've distributed the information there between the head and a new section "introduction". Also, the sentence "it is the complex ratio of the voltage to the current in an alternating current (AC) circuit" is a bit confusing, since the voltage and current are not complex quantities; I've replaced this by "complex representation of" which is more precise. It is important to realise that there is no loss of information: all the content of the previous head is still present in the head or in the introduction. I've also added one sentence of mine regarding AC analysis and the impedance matrix, since it is an important subject, as can be seen in the book of Callegaro.

There remains other things that I intend to improve in the 2-3 next sections: the validity of the complex representation and the derivations of the impedance of R,L and C are not well explained. This subject demands some more deepness. To come in the (not so far) future. maimonid (talk) 06:07, 17 July 2017 (UTC)
 * My network theory text book takes several chapters to go from DC to transient analysis to phasors to complex impedances. It may be too ambitious to try to encapsulate that within an article.  However, if you start with the phasor representation of current and voltage, it may be straight forward. Constant314 (talk) 16:27, 19 July 2017 (UTC)