Talk:Speed of electricity

Wave carries power as well as data?
The article states that the waves, not the electrons carry the data. Does this also apply to power? Calamarain 12:33, 13 June 2007 (UTC)

this doesn't make any sense to me. it's either not explained very well, or it's wrong. it sounds like whoever wrote this is trying to say that electricity is actually the movement of an electromagnetic wave. but i don't think that's true. electricity is like a tightly packed line of electrons. start pushing them forward at one end, and the ones at the other end get pushed forward almost instantly. so information is passed all the way to the end of the line, even though the electrons have only moved a very short distance. it's like the ball pendulum "newton's cradle" that people keep on their desk at work. the resulting electromagnetic wave is only a byproduct. although it is used (in transformers and antennas for example), it isn't the actual vehicle in the transmission of electricity. that's the way i understand it anyway. oh, and in the case of DC, it wouldn't be waves at all. the waves occur because of the oscillation of alternating current. without that oscillation there would only be one crest as the voltage rises to it's peak, then a continuous field, not a wave, and then one last crest as the voltage falls to zero. Thinkdunson (talk) 10:51, 9 March 2008 (UTC)

Data is anything that is perceived and recorded in memory of some sort. Data can be in any perceivable transfer of energy or anything sensed for that matter. The article states that waves carry data and not electrons and this is wrong. This needs to be deleted or rewritten. —Preceding unsigned comment added by Angelmarauder (talk • contribs) 07:54, 5 September 2009 (UTC)

Yes, energy is carried in the electromagnetic waves, not in the electrons. http://en.wikipedia.org/wiki/Poynting_vector  http://amasci.com/miscon/ener1.txt  http://physics.bu.edu/~duffy/py106/EMWaves.html  —Preceding unsigned comment added by 96.224.78.78 (talk) 17:01, 10 November 2010 (UTC)

Yup, both energy AND data are carried by the electromagnetic wave itself. It's a common misconception that the electrons in a wire, cable, etc. carry the power, but actually, it's the electromagnetic field carries the data and power. This misconception arises because of the overly simplistic explanations of electricity that they teach in elementary and high school. In a circuit, wires actually act more like "waveguides", guiding the E-M field from point to point through the air or vacuum immediately surrounding the wire. The electrons in a wire only move *as a consequence* of the external electromagnetic field, NOT THE OTHER WAY AROUND (other than moving charge around to maintain conservation of charge in a circuit, the electrons slowly moving in a wire do nothing other than dissipate energy by creating heat). Refer to the above links on the Poynting vector for a more detailed discussion :P Another thing to remember is that electromagnetic waves on their own (without any conductors in the vicinity) do a perfectly good job of transmitting data. For example, consider a radio or your cellphone. 70.49.49.27 (talk) 03:25, 13 February 2011 (UTC)

The Catt Question. http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=7839341 Ivor Catt — Preceding unsigned comment added by 109.154.34.96 (talk) 06:09, 16 July 2017 (UTC)

Through or over?
Given that electrons travel over the surface of conductors I think the article's first sentence should read "over a conductor" instead of "through a conductor" but I'll let you people decide on that. Thanks. — Preceding unsigned comment added by 87.228.144.254 (talk) 20:47, 8 August 2013 (UTC)


 * At low frequency (approaching DC), the full volume of the conductor is uniformly filled with current. At high frequency the current is confined to the outer skin depth, but it is still inside the conductor.Constant314 (talk) 14:34, 21 September 2013 (UTC)


 * It's a common misconception that electrons only travel over the surface of conductors, a mistake perhaps as a consequence of two definitions of the word "charge." Yes, when a conductor has a net-charge, that charge exists at the surface.  But electric currents are not a flow of net-charge (otherwise we couldn't have any current in uncharged conductors, ground, etc.)  The word "conductor" itself means "material containing mobile charge."  E.g. metals contain an enormous "sea of electrons" throughout their volume, even when they have zero net charge on their surface.  Uncharged charge?  No, just a term with two definitions: "charged" meaning having nanocoulombs of excess charge on the surface, versus "charge" meaning hundreds of coulombs of canceled-out mobile ions or electrons deep inside all conductors.  Electric currents are flows of the charge-sea inside, or what JC Maxwell called the "total electrification." 72.55.203.153 (talk) 02:52, 16 March 2014 (UTC)

Needed?
Could this not be merged into electricity? This is a single point article (ie: Electric moves at the speed of light but electrons drift velocity is very small) so its ot likly to be expanded. CaptinJohn (talk) 10:01, 19 November 2007 (UTC)

This is covered in Electricity. Im going to nominate for merger/deletion unless anyone thinks otherwise?

I agree. This topic could be however explained more in Electricity article. Especially what is causing the electrons to convey electricity at speed of light (electromagnetic waves or collisions?!) and what is actually moving the power and where (electrons on the surface of the conductor?). --Yebbey (talk) 09:01, 11 May 2010 (UTC)

This is a discrete topic that if it were included in the main electricity article would make that article very large indeed. The previous posts demonstrated much of the miss-understanding that exists around wave-particle duality. I suggest this article remain, it is an especially important concept for helping folks understand some simple problems (such as lag in an overseas analog phone system) to complex problems (speed limit of information transfer). —Preceding unsigned comment added by 129.15.112.14 (talk) 15:53, 25 January 2011 (UTC)

Speed of Light in Copper
References online generally point to .5c to .95c with several sources citing 2/3 c. —Preceding unsigned comment added by 207.171.180.101 (talk) 03:43, 7 October 2008 (UTC)

CaptinJohn (talk) 09:58, 21 November 2007 (UTC)

Speed of light *within copper metal* is on the order of meters per second. This is covered in texts on skin effect. Speed of light along insulated transmission lines is determined by the thickness and permittivity of the insulators involved. A microwave waveguide that's filled with blocks of polyethelene is very similar to a coaxial cable with polyethelene insulation inside. I.e. the speed of light in plastic. — Preceding unsigned comment added by 72.55.203.153 (talk) 02:59, 16 March 2014 (UTC)

Error in pdf
At the conclusion of page 2, 0.00234cm/s is converter to 8.42cm/h (which is correct) but then he converts that to mm/h (84) but states it is mm/day. In fact it would be 202.176 cm/day or just over 2m/day!

In the text at the end of page 2, he correctly states 84mm per hour, so I'm guessing the mm/day is just a typo. Iaindb (talk) 00:52, 10 February 2010 (UTC)

Incomprehensible sentence in section: Electromagnetic waves
"The velocity and the electrical resistance outside a conduction is often assumed by the propagation speed of an electromagnetic wave."

I haven't been able to figure out what this is intended to say. Perhaps something more like: In the context of electromagnetic waves, "speed of electricity" often refers to the speed of propagation of the electromagnetic wave.

But what the sentence is saying about some assumption about velocity and "electrical resistance outside a conduction" makes no sense to me.

Hopefully someone can fix this. Gwideman (talk) 07:37, 10 September 2011 (UTC)

—— This whole article is incomprehensible. Sounds like it was written by an electrical engineering professor.

Just answer the question with rough estimates or examples in real life. ( as it is now, I have no idea what the answer is.) — Preceding unsigned comment added by 2600:1700:5200:FB30:E848:9EAE:1A16:5501 (talk) 20:03, 14 September 2019 (UTC)

Flow of electricity
This article is about the speed of electricity, not flow of electricity. Flow refers to how much as in gallons per minute whereas speed is about how fast as in meters per second. Electricity is a phenomenon, not a flowable substance. But if it was a flowable substance it would be most like energy or power. Consider the answers to a couple of questions: “how much electricity did you use last month” and “how much electricity does that lamp use?” The answer to the first question would be in units of energy and the last in units of power. I have to agree that the first sentence and the lede paragraph can be improved, but I don’t think introducing flow of electricity is helpful and in fact is a step in the wrong direction.Constant314 (talk) 18:45, 16 March 2014 (UTC)

I have never heard nor read a formal definition of electricity, and that's why I don't use that word (and maybe, for the same reason the books I've read don't define it.) If I want to refer to charge, current, energy, or power, I use those words instead of electricity. Alej27 (talk) 13:16, 22 September 2020 (UTC)

Improve references
This article has only three references.
 * The first is a book without page numbers.
 * The second is a dictionary without page numbers or even the year of publication; it is not uniquely identifiable.
 * The third is a non-existent web page. I removed it.  The statement it support about the net movement of electrons with AC voltage applied is common knowledge and there are many sources.
 * I am adding the Refimprove tag Constant314 (talk) 14:52, 12 July 2015 (UTC)

Article completely wrong
This article is wrong in that it is entirely based on the Drude's model, which is known (just like the atomic Bohr's model) not to be accurate at all in several ways. Electrons in a metallic conductor do not have a well definite position and thus lack a well defined velocity. One needs to invoke the wavefunction describing the electrons in the material in order to have a correct picture of what's going on. There is no such thing as a drift velocity for electrons in a solid. Electrons in a material are not like a classical ideal gas molecules. — Preceding unsigned comment added by 192.93.101.169 (talk) 13:27, 22 February 2018 (UTC)


 * The important part of the article: that signals travel as electromagnetic waves (mostly) outside a wire should be fine. The section on drift velocity is questionable. Electrons are moving at speeds between zero and the fermi velocity. Net movement is only in partially filled bands, which may be both hole and electron bands. Aluminium, widely used for longer power lines, has significant hole and electron bands, with close to equal contribution from each. It does seem that drift velocity is computed using the total electron density, and not just that due to partially filled bands, sort of by definition. Gah4 (talk) 20:27, 16 March 2018 (UTC)


 * Seems to me that one could mention electron mobility, which is actually, physically, more significant than average drift velocity. Gah4 (talk) 20:35, 16 March 2018 (UTC)


 * I suppose there are four speeds to consider.
 * 1) The speed of the wave carrying energy from the source to the load. This wave propagates in the dielectric and its speed is related to the dielectric constant and is a large fraction of the speed of light.
 * 2) The drift velocity of the conduction electrons which is very slow.
 * 3) The thermal velocity of the random motion of the conduction electrons, which very high.
 * 4) The speed of the wave carrying energy into the conductor which accounts for the heat dissipate there and is very slow (3.22 m/s for 60 Hz into copper, according to Hayt). This is apparently the confusing one.  It is also the velocity that relates to skin depth and the angle of penetration of the wave associated with speed #1 into the conductor. Constant314 (talk) 22:58, 16 March 2018 (UTC)


 * This is my first try with mobile editing, using an Android nook. The velocity of free electrons at 0.025eV isn't all that fast, but the Fermi velocity is pretty fast.Gah4 (talk) 05:27, 17 March 2018 (UTC)
 * You might need to define those terms.Constant314 (talk) 05:33, 17 March 2018 (UTC)


 * I still disagree, when you say that electrons are moving at speeds between zero and the Fermi velocity. If you take the wavefunction of an electron, that is a Bloch wavefunction, and apply the momentum operator to it, you'll find that p psi is not equal to a constant times psi. In other words, the wavefunction of the electron is not eigenstate of the momentum operator. In other words, they do not have a well definite momentum, and hence, velocity/speed. When one speak about the Fermi velocity, one speak of quasiparticles whose momentum is hbar k. These aren't electrons, even though they are associated to the electrons. So, strictly speaking, electrons don't have a well definite speed in a conductor. The closest speed one can assign to them, if one really wants to do it, is indeed the Fermi velocity (for the electrons responsible for conduction) but one must keep in mind that this isn't really the speed of electrons, but of quasiparticles associated to them. — Preceding unsigned comment added by 192.93.101.169 (talk) 14:32, 22 March 2018 (UTC)


 * It isn't quite that bad, but also not good. For many problems, you can use reduced zone scheme, only considering k in the first Brillouin zone. Electrons, being indistinguishable, QM doesn't allow one to ask about a specific individual electron, but only the whole band. Full or empty band is easy, average velocity is zero. And yes, the Bloch functions have to be multiplied by a basis function that takes into account the lattice periodic potential. As noted above, the Fermi velocity is around 1e6 m/s. The lattice spacing is on the order of Angstroms, so an (average) electron passes around 1e16 lattice cells/s. There is, then, a very high frequency modulation to the velocity, which you can easily average over. If you use extended zone scheme, then the momentum (k vector) will keep going up, through successive bands. Quasiparticles come into the discussion when considering electrons at the bottom of an almost empty band, or holes at the top of an almost full band, where you can simplify the physics with an effective mass. The other way to see it, is that the Fermi velocity is the phase velocity, but the useful velocity, in semiconductor physics, is the group velocity of a wave packet. You can then consider electrons moving slightly above the fermi velocity one direction, and slightly below the other direction, for, on the average, slow moving one direction. Gah4 (talk) 21:06, 22 March 2018 (UTC)


 * Good point about the fact that I may not speak about the wavefunction of a single electron, when it is in a solid. I'll study more about this, thanks for pointing this out! Other than that, I don't think Bloch functions have to be multiplied by a basis function that takes into account the lattice periodic potential, because it already has this multiplicative term included. In fact, it's a plane wave multiplied by a periodic function that has the same periodicity of the lattice's. This is essentially Bloch theorem. I still hold the claim that the k you use is not the one of electrons, but the one of quasiparticles in the solid, regardless of where they stand in the bands. It may be the case that these quasiparticles can be thought as having a mass that differs from the one of the electrons when they are at the edges of bands. I didn't study this (yet) so I cannot comment on it.  — Preceding unsigned comment added by 176.163.163.86 (talk) 14:24, 26 March 2018 (UTC)


 * This article is about the speed of electricity. Both terms are vague.  The article aggregates the usage of those terms in reliable sources, so the article cannot be all wrong.  If you think that an importance case is missing then I would have no problem with you adding a section about that case.  However, given the tone and language of the article, I think the model you are using are too technical for this article.  Constant314 (talk) 15:21, 22 March 2018 (UTC)


 * Probably 99.9% of the time, the group velocity of EM waves in the dielectric around the wire is what people want to know. That works for designing PC boards for high-speed circuits.  (The complication that part of the wave is in air, and partly in the board dielectric, has to be worked through.)  That will also tell you the bit spacing of bits on an ethernet cable, for example. But some people want to know what happen in the wire. (Besides being a wave guide, to tell the EM wave which way to go.) Gah4 (talk) 21:06, 22 March 2018 (UTC)

I thought this article was extremely confusing too. The discussion here is much better. Explaining the four different velocities listed by Constant314, and their relation to the Fermi velocity and group velocity is much more helpful. Probably a mention of phase velocity would be a good idea too. Chris.rapson (talk) 04:34, 9 January 2019 (UTC)

Plasma_oscillation
I suggest reading Plasma_oscillation. As noted above, the more usual speed of electronic signals is the speed of an electromagnetic wave guided by the metal. For that to work, the electrons near the surface need to be able to move fast enough to follow the EM field. That is, to be a close (enough) approximation to a perfect conductor. Frequency dependence gives some metals the colors that they have. As the article notes, for many metals this frequency is in the UV. At higher frequencies, metals are transparent. Below it, electrons move to keep electric fields out, and metals reflect. Gah4 (talk) 22:33, 17 August 2018 (UTC)

This is the first I've come across your entry Gah4. Excellent. I will research this thank you. Hazyj (talk) 01:22, 16 April 2019 (UTC)

Whoops. Sorry! The plasma oscillation entry might have been the first I read. It's irrelevant. The issue at hand relates to keeping E&M in phase *within*. In other words ... away from the surface.

Please review Zangwill's treatment of "relaxation". This is crucial to understanding this topic. Hazyj (talk) 01:25, 16 April 2019 (UTC)

index of refraction
As for the speed of electromagnetic waves inside metals, that depends on the index of refraction. Specifically, it is complex, which causes the attenuation of the wave. Using ellipsometry, one can determine the complex index of refraction, and so what the wave does inside a metal. For thin films, the attenuation is low enough to allow some through. Gah4 (talk) 23:12, 17 August 2018 (UTC)


 * Gah4 - please read the link I've provided as well as the lengthy and detailed coverage of the same topic in Talk section with Constant314. In fact I believe Constant, and you and I have already covered the exact points you're making here. Again, please read what I've written already. It's extensive yet not "complete" by Wikipedia standards simply because it will be considered "new" unless I piece together what I will, provided no one gets to it first. In other words, ALL the work is done except for presenting it in "Wiki" fashion. It's all there.

Hazyj (talk) 02:42, 19 August 2018 (UTC)


 * A bit more specific here: there is NO need whatsoever to discuss permittivity (i.e. refractive index) further since it's already been covered extensively by me. The presentation is clear and complete, and has been for months. It's simply not Wiki ready. Regarding the points you're referencing: please find a copy of Zangwill's excellent treatments. It's all there.

Hazyj (talk) 02:48, 19 August 2018 (UTC)


 * A final point since you mentioned it: the common practice of treating good conductors as approximations of "perfect conductors" is the primary culprit that has lead many good texts astray within this context. Again ... Zangwill.

Hazyj (talk) 02:54, 19 August 2018 (UTC)


 * I am not in a rush, but wanted to get those ideas out. For thin films, the effects are easily measurable. Otherwise, I will comment when they are in the article. Gah4 (talk) 06:26, 19 August 2018 (UTC)

Incorrect section: Speed of electromagnetic waves in good conductors
This section is incorrect: displacement current exists within conductors ("good" or otherwise) and it travels at near light speed. I'm gathering my references before I edit this section. I don't think there will be a problem with those. However, there may be two things worth discussing before I edit.

First, as much as I plan to organize the section well and as succinctly as possible, I'm concerned it may get quite long. In particular, I may cover not only the Drude model but others that are modifications of Drude. Is there a sort of wiki rule of thumb about length of sub sections? In my opinion, the edits are both substantial and significant enough to warrant a good length.

Second, Wikipedia isn't the right place for advanced mathematics, and yet it's not clear what is advanced and what isn't. I don't consider any of the math covered in Jackson 2nd Ed chapters 7 or 8 to be advanced, but others may disagree. Hazyj (talk) 00:08, 4 May 2018 (UTC)


 * It depends. Verbatim copies of equations from reliable sources can be quite complicated.  Equations derived from equations in reliable sources will be subject to greater scrutiny. Constant314 (talk) 00:46, 4 May 2018 (UTC)

Thank you. Next question. Since the edits will come across as a revelation to some, they will want to understand why their texts were so incorrect. Since I can't get directly into the minds of Hayt and Balanis, my assertions will come across as nothing but speculation. For that reason I cannot state them directly within the wiki entry. But the subject needs to be addressed in my opinion. Where to do so? In the talk section? Hazyj (talk) 18:10, 4 May 2018 (UTC)
 * Wikipedia does not publish original research, so someone might remove your posting, but as long as it is on the talk page, I won't remove it. Constant314 (talk) 21:02, 4 May 2018 (UTC)

There will be no original research cited anywhere within my Speed of Electricity edits. My question relates to the inevitable questions that will arise because of authors' mistakes regarding this topic. Nothing in my edits will involve original research, but there will likely still be questions as to WHY those authors made the mistakes they did. Hazyj (talk) 21:31, 4 May 2018 (UTC) Hazyj (talk) 23:59, 4 May 2018 (UTC)

Here is a summary of the current state of my edit (assuming I'm the one that corrects this section). I'm hoping for some down time before the end of the year to piece it all together in some coherent fashion. Undoubtedly Zangwill has done exactly that, but as his treatment is advanced it will require some time for me to simplify for wikipedia purposes.

https://www.quora.com/Why-does-my-light-turn-on-quickly-upon-switching-them-on-even-though-electrons-have-a-slow-drift-velocity/answer/John-Ahearn-1 Hazyj (talk) 01:30, 17 August 2018 (UTC)

Just today I noticed that the user going by the name of Constant314 published a Wikipedia notice as follows ... "as edited by Constant314 (talk | contribs) at 21:46, 11 January 2018 (Reverted good faith edits by Hazyj (talk): The section is correct. The references are good and are paraphrased accurately."

I wish I had read this publicly "wiki-accepted" edit 2 years ago, because I certainly would have written this response immediately...

The section is *not correct* and I've written plenty on the topic to ensure that anyone who understands the topic must certainly question the truth of it. Please read at least some of what I've written on the topic. This section is wrong and terribly so. E&M energy, although weak, travels at speeds close to that of light in a vacuum *within* conductors. This energy, as it is absorbed by carriers within the conductor, is responsible for keeping current and potential in phase along the length of the conductor. Hazyj (talk) 23:39, 3 September 2019 (UTC)

I have corrected this section. Sorry for all the published edits. I'm not sure how the first incomplete edit was published as I was previewing everything I wrote. Once an incomplete entry was published though, I decided to edit and publish again immediately instead of trying to figure out how to revert the section. How do you do that anyhow? Regardless, my final edit happening now includes a reference to either Hayt or Balanis who makes it clear they neglect the normal E component within conductors because it's small and not because it's non-existent. Hazyj (talk) 18:12, 1 March 2020 (UTC)

Again, my apologies as I didn't want to publish anything until it was completely done. That should be soon however, so hopefully not too many wiki rules were broken in the process Hazyj (talk) 18:16, 1 March 2020 (UTC)

I have finalized my edit for now, although a correct treatment is advanced and requires delineation of the small and large skin depth cases. I'll remind that the existing entry for normal only propagation *also* requires editing for the two skin depth cases. Any edits or removals to my entry will need to be accompanied by a similar edits or removals there. Hazyj (talk) 18:30, 1 March 2020 (UTC)


 * Thanks for adding this material, however, I think that it should be reorganized to give due weight to case 2. It is true that if the conductor has finite conductivity then to satisfy continuity conditions that there must be a normal component of the E field in the conductor next to the boundary surface.  Again, by continuity, it must propagate at the same speed as the E field in the dielectric on the other side of the boundary.   I did not see any explicit mention of the speed of propagation of the normal component within the transition region, so it may be slightly WP:OR but I don’t have any objection.  Of the three references cited, only Jackson discusses the normal component and he refers to it as being a small correction on page 336 and relegates the discussion to a footnote on page 337.  I would describe Jackson as a graduate level or at least upper division text; most readers won’t go there.  Characterizing the two cases as equal gives undue weight to the second case.  The title of the section is Speed of electromagnetic waves in good conductors and the speed of waves in the transition region is a special case of that.  The section should be reorganized with a discussion of case 1, pretty much as it was, without calling it a case and then at the end a paragraph or paragraphs starting with words such as “There is also a small normal component of the E field in the transition region of the conductor …” an then discuss case 2 as desired. Constant314 (talk) 21:30, 1 March 2020 (UTC)


 * You write "The section should be reorganized with a discussion of case 1, pretty much as it was, without calling it a case and then at the end a paragraph or paragraphs starting with words such as 'There is also a small normal component of the E field in the transition region of the conductor …' an then discuss case 2 as desired." I'll continue to update and reorganize if that's the right way to proceed, but this is not the correct way to do so. Most people reading here will want to know how electricity travels so fast in a transmission line type of config. Most won't be very interested in extremely slow propagation normally in the small skin depth case. The correct way to reorganize involves starting from first principles to show how in large skin depth case, or in transition region, carrier acceleration "throughout" is due to normal E component of displacement current. I'm happy to dive in deeper to explain "why" the E field from displacement is so weak, but reducing the discussion to something that's not very important (i.e. slowly propagating E&M in the normal direction) makes little sense. For now perhaps the best way to proceed is for me to include a small paragraph about displacement current inside and out of the conductor and include references which show how displacement electric field accelerates carriers. True my current entry hasn't been dumbed down enough for many to see the connection between the normal components and the fast axial propagation, but this is mainly because we're discussing in the small skin depth case. Again, if there's going to be a large edit to this section then both cases need to be rewritten or accompanied by the large skin depth case. Not just one or the other. And not in a way that somehow favors slow normal propagation which, again, few people will be interested in.Hazyj (talk) 22:22, 1 March 2020 (UTC)


 * I'm currently in the process of the following two things: 1) using both Jackson and/or Balanis derivations (hopefully both) for magnitude and phase of the small normal component of E field due to displacement, and 2) accompanying the findings from this with magnitude and phase of the magnetic field created by it. If I have time tomorrow or the next day I'll include Poynting vector as well. As always, the issue isn't with the theory or formulae or derviation of these, rather it's precise and acceptable documentation. Everything is right there in Jackson and Balanis though. Hazyj (talk) 02:32, 2 March 2020 (UTC)
 * The section is about propagation within a conductor, which is a fairly simple concept. You are talking about propagation within the transition zone.  Perhaps there should be a separate section for that. Constant314 (talk) 17:02, 2 March 2020 (UTC)


 * That's not correct. Both cases are small skin depth cases they both involve E&M propagation in the exact same "transition zone" to use your phrase. This is exactly why there needs to be equal weight to both cases. One the propagates normally and one that propagates axially (in transmission line case for instance). However, the propagation normally isn't very useful to anyone. It doesn't explain much other than a theoretical understanding of how conduction current creates slow moving wave propagation. It's the axial case that's significant because this case involves light speed E&M propagation within the conductor. For small skin depth that propagation occurs within the "transition zone" - the same zone as the normal case. For large skin depth that propagation occurs everywhere for proper geometries. Once again, people who want to learn about how E&M propagates in a transmission line will come to this wiki and want to know about the fast waves axially. There really isn't much purpose to explaining the other case, but it's valid and needs to be included. Both cases are valid. Hazyj (talk) 17:18, 2 March 2020 (UTC)


 * If you are disputing my input then this is the only route that makes sense to me. https://en.wikipedia.org/wiki/Wikipedia:Accuracy_dispute#Disputed_statement and https://en.wikipedia.org/wiki/Wikipedia:Accuracy_dispute#Handling_content_that_may_be_inaccurate

There would need to be a disputed section on the Talk page. I will be thorough and detailed and will provide links to answers from physicists who agree with me. You will also be disputing both Jackson and Balanis and will need to provide reasoning and documentation to that effect. I'm fine if this is the way you want to do it Hazyj (talk) 17:31, 2 March 2020 (UTC)


 * As explained, I'm still editing to include Poyting vector (magnitude and direction) due to displacement within conductor.Hazyj (talk) 17:47, 2 March 2020 (UTC)


 * If I was to guess as to what might be the single greatest cause of your dispute, it might be that you aren't seeing the incredible magnitude related to magnetic field energy. It's enormous. So when these authors say "discard" or "neglect" displacement they are doing so for this reason. There is much documentation confirming this point.Hazyj (talk) 19:56, 2 March 2020 (UTC)


 * Jackson explicitly neglects displacement current. Constant314 (talk) 00:50, 3 March 2020 (UTC)
 * You need displacement current for capacitors, which have high ∂E/∂t. Inside a conductor, you normally don't have high E or ∂E/∂t. Gah4 (talk) 01:35, 3 March 2020 (UTC)
 * You need displacement current for capacitors, which have high ∂E/∂t. Inside a conductor, you normally don't have high E or ∂E/∂t. Gah4 (talk) 01:35, 3 March 2020 (UTC)

@Constant314: @Gah4: Two critical points as a response ...


 * 1) Jackson is deriving conduction current once charge carriers are accelerated by displacement current.
 * 2) Jackson is clear that displacement current *exists* but is weak relative to large changing H field.

Both points are key to my next edits which will include both the magnitude of the light speed displacement current *after* its energy is imparted to the accelerated carriers, and the value and direction of the Poynting vector related to this light speed displacement current.

Moreover, my current edits mention a relative permittivity almost exactly equal to the of the vacuum. This is important for both Balanis' and Jackson's treatments which both are clear that displacement current exists in a conductor.

Regarding the point about capacitors I'm not following for at least two reasons. A capacitor can have an extremely low value for ∂E/∂t depending on frequency and capacitance. Regarding the state of affairs in a conductor, I've explained above in a way that should answer your concerns.Hazyj (talk) 02:44, 3 March 2020 (UTC)

@Constant314: @Gah4: I'm doubting that a wiki entry is the place to explain how displacement current energy is lost to accelerated carriers. If you disagree and think that explanation (formulas and documentation) might lead to a better entry please let me know.Hazyj (talk) 03:25, 3 March 2020 (UTC)


 * Two points. First Jackson says he neglects displacement currents and then presents his fomulas.  You cannot use that as a leaping off point to say that displacements current are important.  Second, I believe the subject of the detail structure of the EM soltuion in the vicinity of a dielectric/conductor boundary is too estoteric for this article and should be removed. Sorry, but I don't have a suggestion as to where it should be, if anywhere. Constant314 (talk) 04:02, 3 March 2020 (UTC)

@Constant314: As I wrote earlier, a dispute is likely your only viable avenue here. Otherwise you are ignoring all of Jackson's, Balanis and Hayt's treatments. If you misunderstand the issue fine. It's difficult. Obviously. But that's not a reason to ignore good science.Hazyj (talk) 04:12, 3 March 2020 (UTC)


 * No, the issue is that you are attempting to synthesize something that is not in the source and is probably wrong. It has to be explicit in the source.Constant314 (talk) 16:21, 3 March 2020 (UTC)

@Constant314: You are badly misunderstanding this topic, and I will dispute it. Hazyj (talk) 16:31, 3 March 2020 (UTC)

identical particles and the Strong Baseball Principle
I believe not well discussed yet is that electrons are quantum mechanical identical particles. You aren't allowed, for example, to put an electron into one end of a wire and ask when that same electron comes out the other end. One might measure the speed of cars on a freeway by watching one go in, writing down the license number, then watching for that same car to exit later. That would give you an average speed for that car. But quantum mechanics doesn't allow that in the case of electrons in a metal. You might believe that, if you figure out how many electrons are in a wire, when more than that number have gone in, and come out the other end, that some must have gone in and come out, but I believe quantum mechanics doesn't even allow for that. As David Mermin says: ""These are intrinsically quantum-mechanical data, and the lesson from these data is ... that you have to be extraordinarily careful in talking about what might have happened but didn't." Note that Jackson describes classical electrodynamics. (That is the name of the book.) That works well in the case of dielectrics, but not so well for metals. Gah4 (talk) 23:39, 2 March 2020 (UTC) Another quote from the same paper: "I would rather celebrate the strangeness of quantum theory than deny it, because I believe it still has interesting things to teach us about how certain powerful but flawed verbal and mental tools we once took for granted continue to infect our thinking in subtly hidden ways." Gah4 (talk) 00:05, 3 March 2020 (UTC)

What does "signal" mean in this article?
It is said in this article that signals propagate at the speed of light while the electrons move at the drift velocity. But it is nevery clarified what "signal" means in this context. Since electrons is charge, at least I can assume signal is not charge. But what about voltage or current intensity? As far as I know, energy travels at the speed of light. Alej27 (talk) 13:03, 22 September 2020 (UTC)
 * Signal is what is interesting, usually a change in something. That is why there is group velocity (velocity of information) and phase velocity (not related to information flow). Phase velocity is often greater than c. Gah4 (talk) 05:51, 21 December 2020 (UTC)
 * Signal is what is interesting, usually a change in something. That is why there is group velocity (velocity of information) and phase velocity (not related to information flow). Phase velocity is often greater than c. Gah4 (talk) 05:51, 21 December 2020 (UTC)

IP edit 21 December 2020
Hi all, drive by comment: As relates to the last couple of edits, should the statement say potential or field? The IP was right to notice it doesn't make sense to say "in the presence of potential and an electric field". Footlessmouse (talk) 02:19, 21 December 2020 (UTC)