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Archive 1 | Archive 2 | Archive 3 | Archive 4 | Archive 5 | Archive 6 | Archive 7 |
Note that the article to which this talkpage relates was located at Negative impedance for part of its history.
The rewrite performed by User:Circuit-fantasist has been moved from here to User:Circuit-fantasist/Negative resistance. Zetawoof( ζ) 20:51, 17 January 2009 (UTC)
Moved again to here after it was put back. Consensus is that Wikipedia's policies do not permit such content on article Talk pages. The comments immediately below refer directly to the removed contect but have been left in situ to preserve the history of this Talk page. See Archive 3 for recent discussion re this. Secret Squïrrel 01:16, 20 February 2009 (UTC)
There's something very important that's missing here: Sources. Sources, sources, sources. Can you cite some? Zetawoof( ζ) 00:30, 21 January 2009 (UTC)
You can't quote yourself as a source. — BillC talk 22:59, 21 January 2009 (UTC)
I have replaced the introductory part ( Concepts) of the article with the text above. My explanations are so simple, clear and obvious that there is no any need to verify them; all is needed is Ohm's law. Nevertheless, I have wasted mass of time to look for reliable sources (besides my article [1]) that second these speculations. For now, I have found only one expressive picture [2] but I will continue browsing the web. Circuit-fantasist ( talk) 16:25, 24 January 2009 (UTC)
Negative differential resistance and absolute negative resistance are different enough concepts; so, I have moved the main content related to negative differential resistance to the related page. Circuit-fantasist ( talk) 16:58, 24 January 2009 (UTC)
I have created a new page about Deborah Chung's "apparent negative resistance" and moved the related section from this article to it. I have also copied the related text from the old discussion and from the full version of my suggestions for improving the article about negative resistance. Visit the talk page to see my reasons. Circuit-fantasist ( talk) 15:46, 26 January 2009 (UTC)
I have begun reconstructing the introductory text on the top. I have tried to show there the most typical properties of the negative impedance phenomenon as follows:
Please, comment my insertion.
Circuit-fantasist (
talk)
09:15, 28 January 2009 (UTC)
I have renamed the title from "Negative resistance" to "Negative impedance" and redirect the first article to the second one. The reason is that the negative resistance phenomenon is a special case of the more common negative impedance phenomenon. Circuit-fantasist ( talk) 14:35, 28 January 2009 (UTC)
I have started the most interesting part of the article where we have to show how to create negative impedance elements. I have exposed in detail my viewpoint at the topic in the full version of my suggestions for improving the article. Here, I will show the truth about these odd, mystic and never explained circuits by using extremely simple and clear explanations that are obvious for every thinking human being. Please, do not put a damper on my enthusiasm; instead, just help me to reveal the truth! Here are the main points:
I have created the greater part of the most interesting part of the section about negative impedance implementations where we have to show how to create true 2-terminal (one-port) current-driven negative impedance elements... but I'm not contented... I have realized this idea is extremely simple, intuitive and brilliant but yet I have not managed to express it in this way...so, obviously, I have to reword and refine it. Circuit-fantasist ( talk) 10:36, 30 January 2009 (UTC)
I have started my rewrite of Negative Resistance, as I stated I would do some time ago. The ideas about negative impedance described here are terribly misconstrued. The impedance of capacitors and inductors have opposite signs when circuits are analyzed incrementally. This is why resonant circuits work - the inductive and capacitive impedance cancel each other out at their resonant frequency. An Ohmic device always has a positive impedance. There is no way of creating a resonant circuit with resistive devices. So the ideas put forth in this article are fundamentally wrong. I will continue with my edits to Negative Resistance and if this article is not soon deleted I will rewrite it as well. Negative impedance exists, but is not what is described here. Zen-in ( talk) 06:18, 2 February 2009 (UTC)
Zen-in, thank you for your reaction to my work. I appreciate your efforts to improve the page about negative impedance and invite more Wikipedians to join this discussion. All we have the same goal - to show the truth about negative impedance (resistance) phenomenon. I will first comment thoroughly your contentions (in bold and italic) and then I will draw general conclusions. I have also saved below your insertion from the article. Circuit-fantasist ( talk) 17:36, 7 February 2009 (UTC)
"Negative Impedance is an alternative description of an electronic effect called Negative Resistance. Impedance, however refers to the frequency dependent resistance of a component. Components and materials that display a negative resistance effect may have frequency dependent properties as well. There is no contemporary research in this area and so it might be assumed that the term is a holdover from the 19th Century."
...The impedances of capacitors and inductors have opposite signs when circuits are analyzed incrementally... Maybe, the main problem here is that you think in terms of classical electricity while I think in terms of electronic circuitry. In the area of negative impedance phenomena, it is the custom to say that all natural passive components (resistors, capacitors and inductors) absorbing energy from the input source have "positive" impedance (or just impedance in the wide sense of the word, not only as an opposition to a sinusoidal alternating current); so, from this viewpoint, the impedances of capacitors and inductors have the same positive signs. Conversely, the artificial electronic circuits (negative "resistors", negative "capacitors" and negative "inductors") behaving in an opposite way (adding energy to the input source in the same manner as the according passive components) have a true "negative" impedance.
This classification regards to the way of processing energy - "positive impedance" means consuming while "negative impedance" means producing energy. From this viewpoint, "positive impedance" means "ordinary impedance" while "negative impedance" means something opposite as "inverse impedance", "opposite impedance" or "anti-impedance". Then "capacitor" and "inductor" mean elements that absorb energy from the input source and accumulate it into themselves.
This concept is extremely simple, clear and intuitive if we think in terms of voltages when we apply a constant input voltage to the elementary RC and RL circuit. Then, voltage drops appear across capacitors and inductors; they change in a different (opposite) way through time but both they are voltage drops. Conversely, voltages appear across negative capacitors and inductors; they also change in a different (opposite) way through time but now both they are voltages, not voltage drops.
Well, I would like to ask you what a negative impedance converter does. What does it convert? Does it make a capacitor behave as an inductor and v.v., an inductor as a capacitor? No, it doesn't. A gyrator can do this magic. A negative impedance converter can make capacitors and inductors behave as sources (negative impedance elements) instead as passive elements having positive impedance. I hope all these pages listed by Google will persuade you what negative impedance means in this area.
...This is why resonant circuits work - the inductive and capacitive impedance cancel each other out at their resonant frequency... Zen-in, this is a formal explanation of the unique resonance phenomenon that does not explain anything... But let's leave this discussion or move to the according talk page where Wjbeaty has tried to explain the great phenomenon in such an intuitive manner (...a paired coil/capacitor acts as a passive oscillator which essentially sends out an inverse copy of the incoming signal...) as I try to explain here the no less great negative impedance phenomenon. Although there is some resemblance between them the negative impedance phenomenon is quite different from the resonance phenomenon: negative impedance is a process of injecting additional energy (by an additional outer source) while resonance is a process of using a treasured energy (it is drawn by the input source, not by another source). If you want to say something about resonance here, say that negative impedance is extremely useful for resonant circuits as LC generators are based on the combination resonator + negative resistor.
...An Ohmic device always has a positive impedance... Of course, I second this assertion; who has said the opposite? Only electrical sources can possess true negative impedance (see what negative impedance is).
...There is no way of creating a resonant circuit with resistive devices... Who has said the opposite? There is no such assertion in the article.
...Previously this was extremely overdone,... What do you want to say? Negative impedance (resistance) phenomenon is very, very important. For example, all the op-amp inverting circuits (1,020,000 pages showed by Google) based on the presence of virtual ground (have I to list them?) exploit this powerful idea (of course, if you can see it), the legendary Howland current source (pump) (46,000 pages) and Deboo integrator (4,000 pages) are negative impedance circuits (again, if you are able to discern the great idea), telephony line reperitors are negative "resistors" connected in series... negative impedance converters (120,000 pages), gyrators...have I to continue? The ubiquitous virtual ground phenomenon (448,000 pages!!!) is based on the negative impedance phenomenon; it is a result of "neutralization" between opposite impedances - "positive" and "negative". However, negative impedance (especially true negative impedance) is not explained in a satisfactory way somewhere on the web; there are only particular speculations mainly about differential negative resistance. As a rule, the authors don't distinguish the two kinds of resistances although they are completely different by their nature. See in forums how many people (425,000 pages!!!) want to know what a negative impedance (resistance) is! All they ask, What is a negative resistance?, Does the resistance can be negative?, Have you heard about negative resistance?, etc. So, negative impedance phenomenon deserves to be explained satisfactory.
Zen-in, as I can see, you have a tendency for extreme actions. I wonder how it is possible to see that someone has gone out of his way to make clear such an unintelligible circuit phenomenon and, at the same time, to remove completely his work?!? Wikipedia is neither yours nor mine. We shouldn't forget its main idea; we have to join our forces in revealing the truth about circuits instead to impede each other. We have to behave as negative impedance elements instead as "positive" impedance ones:)
IMO, a possible solution to eliminate the ambiguity in the meaning of "negative impedance" is to insert some explanation in the lede and to add a link to Electrical impedance; you can do it. Circuit-fantasist ( talk) 17:36, 7 February 2009 (UTC)
This is all fringe thought; what we call pseudo-Science. It doesn't merit being called Engineering. This entire page is simply put a result of your over-active imagination. Can you produce a reference to support any of your ideas? No, because they are all yours. I have a very large library of EE texts by most of the best authors. Nowhere in any of these books is there anything remotely close to what you have written. Negative resistance is well documented. The impedance of negative resistance materials is also well documented. Negative impedance is your idea. Wikipedia is an encyclopedia and is not the place for unsupported research. The purpose of any Engineering pursuit is to become adept at designing useful devices. Those who pursue a career in Electrical Engineering consider themselves fortunate if they eventually learn how to design circuits (among many other options). It is to this goal that EE texts and Wikipedia articles on the subject are directed. I design electronics using mathematical methods. This is something I have been doing for a long time. Your descriptions of circuits don't offer anyone any methods of how to design. Instead they are like a http://en.wikipedia.org/wiki/Cargo_cult view of electronics. You look at a circuit that someone else has designed and you apply your alternative description of it, complete with crayon drawings of silly stickmen. No one reading your work will be left with an increased ability to design a similar circuit. It is all just confused gibberish. Other concerned Wikipedians hopefully will follow my lead and will remove your grafitti. Zen-in ( talk) 19:16, 7 February 2009 (UTC)
Negative impedance is not a term that is in general use by Electrical Engineers. The only place where this term could possibly be used would be as it applies to the direct measurement of impedance with a Boonton Rx Bridge or similar device. These instruments are used to measure the impedance magnitude and phase of a 2 port device. The imaginary component of the impedance is measured by adjusting the X control until a meter has been nulled. The dial markings on this control are marked in negative and positive mmf (now termed pf). When measuring the impedance of a 2-port component with this instrument, a negative reading indicates a capacitive impedance. This designation of a capacitive impedance having a negative sign is purely arbitrary. Modern network analyzers and Scattering parameters notation use the opposite convention. However, RF Engineers use the term Complex conjugate when considering impedance matching. Zen-in
Zen-in ( talk) 01:41, 18 February 2009 (UTC)
<outdent> Just in case that has confused anyone, Zen-in has copy-and-pasted the above discussion from my talk page. As I replied there, this article is not forked, it was moved. It is the earlier article as the edit history shows. The article that is currently at negative resistance is a much later creation and is therefore the fork. That is not to say anything about which article is better. My only point here is that creating another article is not the answer to a bad article. The right approach is to improve the original bad article. SpinningSpark 18:29, 18 February 2009 (UTC)
There seems to have been a consensus reached at the negative resistance article (which is currently deleted) that this article should be moved there. Before anyone actually makes the move, can we have a quick straw poll just to make sure? There may be people watching this page who were not watching the other one. SpinningSpark 18:03, 19 February 2009 (UTC)
Note also that there is a redirect page at Negative Resistance which probably should be cleaned up along with this move as well.— Tetracube ( talk) 18:35, 19 February 2009 (UTC)
Ok, we have consensus. I have moved the page. Will tidy up redirects. Will look at renaming the archives so that anyone popping in here will know what's from where. Secret Squïrrel 00:44, 20 February 2009 (UTC)
I think it would be good to have a graph of a theoretical negative resistor near the start of the article, just for illustrative purposes. That graph of a GaAs Tunnel Diode is a bit overused on Wikipedia, but something similar would be good to have as well. I will see what I can produce unless someone beats me to it. Zen-in ( talk) 00:59, 20 February 2009 (UTC)
Some of the current images don't look "encyclopedic" and are a bit cluttered. Several of them also aren't necessary and should be removed.
Circuit-fantasist: I like some of your "Current-driven negative impedance elements" section, but it's currently too long and overly simplified. It would be great if you could make it more concise so we can perhaps salvage some of it. I could also use some help with the definition. -Roger ( talk) 04:08, 20 February 2009 (UTC)
I added more to the start of the article; don't know if I am getting into too much detail. There are some better transfer curves for Tunnel Diodes in a manual I have. I'll scan the pages and maybe someone more skilled in gnuplot than I can transform them. Zen-in ( talk) 05:55, 20 February 2009 (UTC)
Deborah Chung's "Apparent Negative Resistance" may be more accurately described as a Meta_material than an example of negative resistance, due to energy considerations. Also the work was done over 10 years ago and may not have been replicated. Zen-in ( talk) 06:05, 20 February 2009 (UTC)
I have been looking at the op-amp implementation of a negative resistor under this title and I think the analysis overlooks a key aspect of how op-amps work. op-amps Any analysis of an op-amp circuit assumes the inputs are high impedance and are always at the same potential. A voltage across the inputs makes the output rail like a comparator, and no current flows between the inputs. Using a current source will not result in a voltage being produced across the inputs. Op-amp gains are always more than 1; usually over 100,000. I found an op-amp circuit that does emulate a negative resistor - http://commons.wikimedia.org/wiki/File:Op-Amp_Negative_Impedance_Converter.svg. I did the math and it checks out. Zen-in ( talk) 08:22, 20 February 2009 (UTC)
I've moved the ensuing conversation to Negative impedance, not resistance. -- Timberframe ( talk) 21:49, 20 February 2009 (UTC)
I find the stuff about Gabriel Kron highly dubious. As far as I can make out his use of negative resistance arises from a rather weird method of solving the Schrodinger equation by means of analogy with electric circuits. It is entirely a mathematical construct and has nothing whatsover to do with electronics (the article this comes from is titled Early ideas in the history of quantum chemistry). The idea that he actually made a negative resistor seems to have originated here which is a personal website and in my opinion is utterly misrepresenting his work. In any case it cannot be cosidered reliable. I will put in the history according to Belevich who is a reliable source for all things on electrical network history. I will refrain from deleting the Kron stuff for now just in case I am completely wrong even though that may mean there are temporarily some contradictions in the text. Please comment. SpinningSpark 15:22, 20 February 2009 (UTC)
This is kind of a general question, but it also applies to this article. Is showing circuit analysis steps really encouraged, instead of just stating the final result (perhaps with some minor explanation)? Personally I do sometimes like having the derivations, but they tend to clutter things and don't really seem encyclopedic. -Roger ( talk) 20:07, 20 February 2009 (UTC)
Wikipedia's circuit pages have an odd obsession with the term "resistance." Pages should be made more general. This page should be renamed "negative impedance." Likewise, Negative impedance converter should show generic impedances rather than resistances. — TedPavlic ( talk) 20:14, 20 February 2009 (UTC)
Earlier conversation moved here from Basic active negative resistor:
Circuit-fantasist, thank you for re-organising the article. That is now much more logical, a lot of the recent major changes got things out of order. I just have one suggestion, I notice you have changed some of the titles from negative resistance to negative impedance. A lot of the editors here want a negative resistance article. Can we just discusss negative resistance at the beginning of the article and then move on to negative impedance further down? That has the benefit of making it easier for readers who struggle with complex notation. It will also make it easier if we decide to split out the negative impedance part in to another article. Thanks. SpinningSpark 14:57, 21 February 2009 (UTC)
I removed the first op-amp circuit because it really just has bistable operation. The DC gain of op-amps is very high = > 100,000. There was also a lot of left over stuff that was difficult to read. C-F please don't revert this as soon as you see it. I think everyone should have a look at the article as it now stands and if the consensus is that we should put some of it back we can do that. The properties section needs some work still. Zen-in ( talk) 17:29, 21 February 2009 (UTC)
It is more than obvious that, in order to create this part of the article, we (Wikipedia editors, responsible for it) have to understand all these op-amp circuits. Otherwise, it would be very confusing if we "explain" these circuits to people but the very we do not know what the basic ideas behind them are. But what does "to understand circuits" mean?
Generally speaking, it means to find out all about each of the components constituting the circuit: why it is added to the circuit, what its function is, what it does, how it does it, what its value has to be, etc. Then we have to discern groups of components constituting familiar sub-circuits and to clarify its role. Especially for the present op-amp circuits we have to know the role of the positive impedance element connected between the op-amp output and the non-inverting input, the role of the voltage divider connected between op-amp output and the inverting input and, of course, the role of the very op-amp. Please, answer the concrete questions below and suggest possible circuit explanations. Circuit-fantasist ( talk) 15:37, 22 February 2009 (UTC)
What does the resistor R do? What does the op-amp do? How does the circuit behave when connected in parallel to a load load with resistance R driven by a real input voltage source?
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What does the resistor R do? What do the resistors R1 do? What does the op-amp do? How does the circuit behave when connected in parallel to a load load with resistance R driven by a real input voltage source?
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What does the capacitor C do? What do the resistors R1 do? What does the op-amp do? How does the circuit behave when connected in parallel to a load with capacitance C driven by a real input voltage source?
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What do positive impedance element Z do? What do the resistors R1 do? What does the op-amp do? How does the circuit behave when connected in parallel to a load with impedance Z driven by a real input voltage source?
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What does the resistor R1 do? What do the resistor R1 do? What do the capacitor C do? What do the combination R1-C do? What does the op-amp do? How has the inductance achieved? How does the circuit behave when connected in parallel to a load with inductance L driven by a real input voltage source?
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This page is already 84 kilobytes long. I suggest to archive (at least the first part of) it. Circuit-fantasist ( talk) 14:11, 22 February 2009 (UTC)
![]() | This page is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page. |
![]() | This is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page. |
Archive 1 | Archive 2 | Archive 3 | Archive 4 | Archive 5 | Archive 6 | Archive 7 |
Note that the article to which this talkpage relates was located at Negative impedance for part of its history.
The rewrite performed by User:Circuit-fantasist has been moved from here to User:Circuit-fantasist/Negative resistance. Zetawoof( ζ) 20:51, 17 January 2009 (UTC)
Moved again to here after it was put back. Consensus is that Wikipedia's policies do not permit such content on article Talk pages. The comments immediately below refer directly to the removed contect but have been left in situ to preserve the history of this Talk page. See Archive 3 for recent discussion re this. Secret Squïrrel 01:16, 20 February 2009 (UTC)
There's something very important that's missing here: Sources. Sources, sources, sources. Can you cite some? Zetawoof( ζ) 00:30, 21 January 2009 (UTC)
You can't quote yourself as a source. — BillC talk 22:59, 21 January 2009 (UTC)
I have replaced the introductory part ( Concepts) of the article with the text above. My explanations are so simple, clear and obvious that there is no any need to verify them; all is needed is Ohm's law. Nevertheless, I have wasted mass of time to look for reliable sources (besides my article [1]) that second these speculations. For now, I have found only one expressive picture [2] but I will continue browsing the web. Circuit-fantasist ( talk) 16:25, 24 January 2009 (UTC)
Negative differential resistance and absolute negative resistance are different enough concepts; so, I have moved the main content related to negative differential resistance to the related page. Circuit-fantasist ( talk) 16:58, 24 January 2009 (UTC)
I have created a new page about Deborah Chung's "apparent negative resistance" and moved the related section from this article to it. I have also copied the related text from the old discussion and from the full version of my suggestions for improving the article about negative resistance. Visit the talk page to see my reasons. Circuit-fantasist ( talk) 15:46, 26 January 2009 (UTC)
I have begun reconstructing the introductory text on the top. I have tried to show there the most typical properties of the negative impedance phenomenon as follows:
Please, comment my insertion.
Circuit-fantasist (
talk)
09:15, 28 January 2009 (UTC)
I have renamed the title from "Negative resistance" to "Negative impedance" and redirect the first article to the second one. The reason is that the negative resistance phenomenon is a special case of the more common negative impedance phenomenon. Circuit-fantasist ( talk) 14:35, 28 January 2009 (UTC)
I have started the most interesting part of the article where we have to show how to create negative impedance elements. I have exposed in detail my viewpoint at the topic in the full version of my suggestions for improving the article. Here, I will show the truth about these odd, mystic and never explained circuits by using extremely simple and clear explanations that are obvious for every thinking human being. Please, do not put a damper on my enthusiasm; instead, just help me to reveal the truth! Here are the main points:
I have created the greater part of the most interesting part of the section about negative impedance implementations where we have to show how to create true 2-terminal (one-port) current-driven negative impedance elements... but I'm not contented... I have realized this idea is extremely simple, intuitive and brilliant but yet I have not managed to express it in this way...so, obviously, I have to reword and refine it. Circuit-fantasist ( talk) 10:36, 30 January 2009 (UTC)
I have started my rewrite of Negative Resistance, as I stated I would do some time ago. The ideas about negative impedance described here are terribly misconstrued. The impedance of capacitors and inductors have opposite signs when circuits are analyzed incrementally. This is why resonant circuits work - the inductive and capacitive impedance cancel each other out at their resonant frequency. An Ohmic device always has a positive impedance. There is no way of creating a resonant circuit with resistive devices. So the ideas put forth in this article are fundamentally wrong. I will continue with my edits to Negative Resistance and if this article is not soon deleted I will rewrite it as well. Negative impedance exists, but is not what is described here. Zen-in ( talk) 06:18, 2 February 2009 (UTC)
Zen-in, thank you for your reaction to my work. I appreciate your efforts to improve the page about negative impedance and invite more Wikipedians to join this discussion. All we have the same goal - to show the truth about negative impedance (resistance) phenomenon. I will first comment thoroughly your contentions (in bold and italic) and then I will draw general conclusions. I have also saved below your insertion from the article. Circuit-fantasist ( talk) 17:36, 7 February 2009 (UTC)
"Negative Impedance is an alternative description of an electronic effect called Negative Resistance. Impedance, however refers to the frequency dependent resistance of a component. Components and materials that display a negative resistance effect may have frequency dependent properties as well. There is no contemporary research in this area and so it might be assumed that the term is a holdover from the 19th Century."
...The impedances of capacitors and inductors have opposite signs when circuits are analyzed incrementally... Maybe, the main problem here is that you think in terms of classical electricity while I think in terms of electronic circuitry. In the area of negative impedance phenomena, it is the custom to say that all natural passive components (resistors, capacitors and inductors) absorbing energy from the input source have "positive" impedance (or just impedance in the wide sense of the word, not only as an opposition to a sinusoidal alternating current); so, from this viewpoint, the impedances of capacitors and inductors have the same positive signs. Conversely, the artificial electronic circuits (negative "resistors", negative "capacitors" and negative "inductors") behaving in an opposite way (adding energy to the input source in the same manner as the according passive components) have a true "negative" impedance.
This classification regards to the way of processing energy - "positive impedance" means consuming while "negative impedance" means producing energy. From this viewpoint, "positive impedance" means "ordinary impedance" while "negative impedance" means something opposite as "inverse impedance", "opposite impedance" or "anti-impedance". Then "capacitor" and "inductor" mean elements that absorb energy from the input source and accumulate it into themselves.
This concept is extremely simple, clear and intuitive if we think in terms of voltages when we apply a constant input voltage to the elementary RC and RL circuit. Then, voltage drops appear across capacitors and inductors; they change in a different (opposite) way through time but both they are voltage drops. Conversely, voltages appear across negative capacitors and inductors; they also change in a different (opposite) way through time but now both they are voltages, not voltage drops.
Well, I would like to ask you what a negative impedance converter does. What does it convert? Does it make a capacitor behave as an inductor and v.v., an inductor as a capacitor? No, it doesn't. A gyrator can do this magic. A negative impedance converter can make capacitors and inductors behave as sources (negative impedance elements) instead as passive elements having positive impedance. I hope all these pages listed by Google will persuade you what negative impedance means in this area.
...This is why resonant circuits work - the inductive and capacitive impedance cancel each other out at their resonant frequency... Zen-in, this is a formal explanation of the unique resonance phenomenon that does not explain anything... But let's leave this discussion or move to the according talk page where Wjbeaty has tried to explain the great phenomenon in such an intuitive manner (...a paired coil/capacitor acts as a passive oscillator which essentially sends out an inverse copy of the incoming signal...) as I try to explain here the no less great negative impedance phenomenon. Although there is some resemblance between them the negative impedance phenomenon is quite different from the resonance phenomenon: negative impedance is a process of injecting additional energy (by an additional outer source) while resonance is a process of using a treasured energy (it is drawn by the input source, not by another source). If you want to say something about resonance here, say that negative impedance is extremely useful for resonant circuits as LC generators are based on the combination resonator + negative resistor.
...An Ohmic device always has a positive impedance... Of course, I second this assertion; who has said the opposite? Only electrical sources can possess true negative impedance (see what negative impedance is).
...There is no way of creating a resonant circuit with resistive devices... Who has said the opposite? There is no such assertion in the article.
...Previously this was extremely overdone,... What do you want to say? Negative impedance (resistance) phenomenon is very, very important. For example, all the op-amp inverting circuits (1,020,000 pages showed by Google) based on the presence of virtual ground (have I to list them?) exploit this powerful idea (of course, if you can see it), the legendary Howland current source (pump) (46,000 pages) and Deboo integrator (4,000 pages) are negative impedance circuits (again, if you are able to discern the great idea), telephony line reperitors are negative "resistors" connected in series... negative impedance converters (120,000 pages), gyrators...have I to continue? The ubiquitous virtual ground phenomenon (448,000 pages!!!) is based on the negative impedance phenomenon; it is a result of "neutralization" between opposite impedances - "positive" and "negative". However, negative impedance (especially true negative impedance) is not explained in a satisfactory way somewhere on the web; there are only particular speculations mainly about differential negative resistance. As a rule, the authors don't distinguish the two kinds of resistances although they are completely different by their nature. See in forums how many people (425,000 pages!!!) want to know what a negative impedance (resistance) is! All they ask, What is a negative resistance?, Does the resistance can be negative?, Have you heard about negative resistance?, etc. So, negative impedance phenomenon deserves to be explained satisfactory.
Zen-in, as I can see, you have a tendency for extreme actions. I wonder how it is possible to see that someone has gone out of his way to make clear such an unintelligible circuit phenomenon and, at the same time, to remove completely his work?!? Wikipedia is neither yours nor mine. We shouldn't forget its main idea; we have to join our forces in revealing the truth about circuits instead to impede each other. We have to behave as negative impedance elements instead as "positive" impedance ones:)
IMO, a possible solution to eliminate the ambiguity in the meaning of "negative impedance" is to insert some explanation in the lede and to add a link to Electrical impedance; you can do it. Circuit-fantasist ( talk) 17:36, 7 February 2009 (UTC)
This is all fringe thought; what we call pseudo-Science. It doesn't merit being called Engineering. This entire page is simply put a result of your over-active imagination. Can you produce a reference to support any of your ideas? No, because they are all yours. I have a very large library of EE texts by most of the best authors. Nowhere in any of these books is there anything remotely close to what you have written. Negative resistance is well documented. The impedance of negative resistance materials is also well documented. Negative impedance is your idea. Wikipedia is an encyclopedia and is not the place for unsupported research. The purpose of any Engineering pursuit is to become adept at designing useful devices. Those who pursue a career in Electrical Engineering consider themselves fortunate if they eventually learn how to design circuits (among many other options). It is to this goal that EE texts and Wikipedia articles on the subject are directed. I design electronics using mathematical methods. This is something I have been doing for a long time. Your descriptions of circuits don't offer anyone any methods of how to design. Instead they are like a http://en.wikipedia.org/wiki/Cargo_cult view of electronics. You look at a circuit that someone else has designed and you apply your alternative description of it, complete with crayon drawings of silly stickmen. No one reading your work will be left with an increased ability to design a similar circuit. It is all just confused gibberish. Other concerned Wikipedians hopefully will follow my lead and will remove your grafitti. Zen-in ( talk) 19:16, 7 February 2009 (UTC)
Negative impedance is not a term that is in general use by Electrical Engineers. The only place where this term could possibly be used would be as it applies to the direct measurement of impedance with a Boonton Rx Bridge or similar device. These instruments are used to measure the impedance magnitude and phase of a 2 port device. The imaginary component of the impedance is measured by adjusting the X control until a meter has been nulled. The dial markings on this control are marked in negative and positive mmf (now termed pf). When measuring the impedance of a 2-port component with this instrument, a negative reading indicates a capacitive impedance. This designation of a capacitive impedance having a negative sign is purely arbitrary. Modern network analyzers and Scattering parameters notation use the opposite convention. However, RF Engineers use the term Complex conjugate when considering impedance matching. Zen-in
Zen-in ( talk) 01:41, 18 February 2009 (UTC)
<outdent> Just in case that has confused anyone, Zen-in has copy-and-pasted the above discussion from my talk page. As I replied there, this article is not forked, it was moved. It is the earlier article as the edit history shows. The article that is currently at negative resistance is a much later creation and is therefore the fork. That is not to say anything about which article is better. My only point here is that creating another article is not the answer to a bad article. The right approach is to improve the original bad article. SpinningSpark 18:29, 18 February 2009 (UTC)
There seems to have been a consensus reached at the negative resistance article (which is currently deleted) that this article should be moved there. Before anyone actually makes the move, can we have a quick straw poll just to make sure? There may be people watching this page who were not watching the other one. SpinningSpark 18:03, 19 February 2009 (UTC)
Note also that there is a redirect page at Negative Resistance which probably should be cleaned up along with this move as well.— Tetracube ( talk) 18:35, 19 February 2009 (UTC)
Ok, we have consensus. I have moved the page. Will tidy up redirects. Will look at renaming the archives so that anyone popping in here will know what's from where. Secret Squïrrel 00:44, 20 February 2009 (UTC)
I think it would be good to have a graph of a theoretical negative resistor near the start of the article, just for illustrative purposes. That graph of a GaAs Tunnel Diode is a bit overused on Wikipedia, but something similar would be good to have as well. I will see what I can produce unless someone beats me to it. Zen-in ( talk) 00:59, 20 February 2009 (UTC)
Some of the current images don't look "encyclopedic" and are a bit cluttered. Several of them also aren't necessary and should be removed.
Circuit-fantasist: I like some of your "Current-driven negative impedance elements" section, but it's currently too long and overly simplified. It would be great if you could make it more concise so we can perhaps salvage some of it. I could also use some help with the definition. -Roger ( talk) 04:08, 20 February 2009 (UTC)
I added more to the start of the article; don't know if I am getting into too much detail. There are some better transfer curves for Tunnel Diodes in a manual I have. I'll scan the pages and maybe someone more skilled in gnuplot than I can transform them. Zen-in ( talk) 05:55, 20 February 2009 (UTC)
Deborah Chung's "Apparent Negative Resistance" may be more accurately described as a Meta_material than an example of negative resistance, due to energy considerations. Also the work was done over 10 years ago and may not have been replicated. Zen-in ( talk) 06:05, 20 February 2009 (UTC)
I have been looking at the op-amp implementation of a negative resistor under this title and I think the analysis overlooks a key aspect of how op-amps work. op-amps Any analysis of an op-amp circuit assumes the inputs are high impedance and are always at the same potential. A voltage across the inputs makes the output rail like a comparator, and no current flows between the inputs. Using a current source will not result in a voltage being produced across the inputs. Op-amp gains are always more than 1; usually over 100,000. I found an op-amp circuit that does emulate a negative resistor - http://commons.wikimedia.org/wiki/File:Op-Amp_Negative_Impedance_Converter.svg. I did the math and it checks out. Zen-in ( talk) 08:22, 20 February 2009 (UTC)
I've moved the ensuing conversation to Negative impedance, not resistance. -- Timberframe ( talk) 21:49, 20 February 2009 (UTC)
I find the stuff about Gabriel Kron highly dubious. As far as I can make out his use of negative resistance arises from a rather weird method of solving the Schrodinger equation by means of analogy with electric circuits. It is entirely a mathematical construct and has nothing whatsover to do with electronics (the article this comes from is titled Early ideas in the history of quantum chemistry). The idea that he actually made a negative resistor seems to have originated here which is a personal website and in my opinion is utterly misrepresenting his work. In any case it cannot be cosidered reliable. I will put in the history according to Belevich who is a reliable source for all things on electrical network history. I will refrain from deleting the Kron stuff for now just in case I am completely wrong even though that may mean there are temporarily some contradictions in the text. Please comment. SpinningSpark 15:22, 20 February 2009 (UTC)
This is kind of a general question, but it also applies to this article. Is showing circuit analysis steps really encouraged, instead of just stating the final result (perhaps with some minor explanation)? Personally I do sometimes like having the derivations, but they tend to clutter things and don't really seem encyclopedic. -Roger ( talk) 20:07, 20 February 2009 (UTC)
Wikipedia's circuit pages have an odd obsession with the term "resistance." Pages should be made more general. This page should be renamed "negative impedance." Likewise, Negative impedance converter should show generic impedances rather than resistances. — TedPavlic ( talk) 20:14, 20 February 2009 (UTC)
Earlier conversation moved here from Basic active negative resistor:
Circuit-fantasist, thank you for re-organising the article. That is now much more logical, a lot of the recent major changes got things out of order. I just have one suggestion, I notice you have changed some of the titles from negative resistance to negative impedance. A lot of the editors here want a negative resistance article. Can we just discusss negative resistance at the beginning of the article and then move on to negative impedance further down? That has the benefit of making it easier for readers who struggle with complex notation. It will also make it easier if we decide to split out the negative impedance part in to another article. Thanks. SpinningSpark 14:57, 21 February 2009 (UTC)
I removed the first op-amp circuit because it really just has bistable operation. The DC gain of op-amps is very high = > 100,000. There was also a lot of left over stuff that was difficult to read. C-F please don't revert this as soon as you see it. I think everyone should have a look at the article as it now stands and if the consensus is that we should put some of it back we can do that. The properties section needs some work still. Zen-in ( talk) 17:29, 21 February 2009 (UTC)
It is more than obvious that, in order to create this part of the article, we (Wikipedia editors, responsible for it) have to understand all these op-amp circuits. Otherwise, it would be very confusing if we "explain" these circuits to people but the very we do not know what the basic ideas behind them are. But what does "to understand circuits" mean?
Generally speaking, it means to find out all about each of the components constituting the circuit: why it is added to the circuit, what its function is, what it does, how it does it, what its value has to be, etc. Then we have to discern groups of components constituting familiar sub-circuits and to clarify its role. Especially for the present op-amp circuits we have to know the role of the positive impedance element connected between the op-amp output and the non-inverting input, the role of the voltage divider connected between op-amp output and the inverting input and, of course, the role of the very op-amp. Please, answer the concrete questions below and suggest possible circuit explanations. Circuit-fantasist ( talk) 15:37, 22 February 2009 (UTC)
What does the resistor R do? What does the op-amp do? How does the circuit behave when connected in parallel to a load load with resistance R driven by a real input voltage source?
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What does the resistor R do? What do the resistors R1 do? What does the op-amp do? How does the circuit behave when connected in parallel to a load load with resistance R driven by a real input voltage source?
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What does the capacitor C do? What do the resistors R1 do? What does the op-amp do? How does the circuit behave when connected in parallel to a load with capacitance C driven by a real input voltage source?
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What do positive impedance element Z do? What do the resistors R1 do? What does the op-amp do? How does the circuit behave when connected in parallel to a load with impedance Z driven by a real input voltage source?
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What does the resistor R1 do? What do the resistor R1 do? What do the capacitor C do? What do the combination R1-C do? What does the op-amp do? How has the inductance achieved? How does the circuit behave when connected in parallel to a load with inductance L driven by a real input voltage source?
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This page is already 84 kilobytes long. I suggest to archive (at least the first part of) it. Circuit-fantasist ( talk) 14:11, 22 February 2009 (UTC)
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