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Physics C‑class Mid‑importance

This article is within the scope of WikiProject Physics, a collaborative effort to improve the coverage of Physics on Misplaced Pages. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.PhysicsWikipedia:WikiProject PhysicsTemplate:WikiProject Physicsphysics C This article has been rated as C-class on Misplaced Pages's content assessment scale. Mid This article has been rated as Mid-importance on the project's importance scale.

Archives

Archive 1 - 2005 Archive 2 - 2006 - 2008 Archive 3 - 1 Jan - 19 Feb 2009 Archive 4 - 17 Jan - 22 Feb 2009

Archiving

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)

I have a better idea: Remove your graffiti Zen-in (talk) 20:45, 22 February 2009 (UTC)

Agreed, now archived. C-F we do not need a detailed discussion of the circuit on the talk page. This is not the place to gain an understanding of the circuitry. Not in the article either except where it specifically relates to negative impedance. A general discussion of op-amp design principles belongs in another article. SpinningSpark 21:36, 22 February 2009 (UTC)

Material removed

Material not appropriate for talk pages moved to user space. SpinningSpark 16:29, 27 February 2009 (UTC)

Templates

What templates do we still need? I think they can largely be removed, any remaining problem text can be individually tagged. SpinningSpark 22:47, 22 February 2009 (UTC)

I removed them and added a cleanup tag. The article's getting better, but it still needs some work. -Roger (talk) 23:37, 22 February 2009 (UTC)

I don't think a general cleanup template is very helpful to editors coming to this article new in its current improved state. As I said above, I think we need to tag individual sections, or better still sentences, for improvement now. SpinningSpark 16:43, 27 February 2009 (UTC)

I-V diagrams

What is the purpose of the diagonal lines in the I-V diagram in the properties section? I cannot see what information they are adding. I am inclined to produce a cleaner, simpler diagram. Thoughts? Also, the tunnel diode I-V diagram is a bit innacurate according to my textbooks. I am inclined to redo that one as well, or at least re-legend the diagram to make it clear it is not realistic. SpinningSpark 23:04, 22 February 2009 (UTC)

Spinningspark, the diagonal green lines represent the moving IV curve of the varying input real current source; the vertical red lines represent the moving IV curve of the varying voltage source acting as a true negative resistor. My idea is to show how the true negative resistance IV curve is obtained. See also the text below:

The graphoanalytical interpretation of the negative resistance phenomenon is shown on the figure. It is supposed the negative resistor is driven by a real current source. When the input current varies, the voltage source representing the negative "resistor" changes its voltage. As a result, its IV curve moves and the crossing operating point slides over a new dynamic IV curve representing the negative resistance. It is not a real IV curve; it is an artificial, imaginary IV curve having a negative slope and passing through the origin of the coordinate system. Circuit-fantasist (talk) 23:19, 22 February 2009 (UTC)

Good idea, I think it needs to be simplified, if not eliminated. The only possible use of it I can imagine is showing the boundary between positive and negative resistance. -Roger (talk) 23:40, 22 February 2009 (UTC)

Ok, I'll get on it next week, it's quite late now and I am going to be away on business most of the week. SpinningSpark 00:09, 23 February 2009 (UTC)

User:BillC said he would help out by converting scans from a Tunnel Diode manual I have. I agree the negative resistance IV diagram needs redoing, maybe with a derivation showing how a theoretical negative resistor delivers power to the load. There is an example problem in Desoer & Kuh, Basic Circuit Theory. I will do the analysis and see if I can create a diagram. This may be an aspect of negative resistors that is considered self-evident so may not be needed. Zen-in (talk) 00:24, 23 February 2009 (UTC)

Howland circuit

The Howland voltage to current circuit is not a negative resistance device, or at least I cannot find a source that says it is, and putting in some trial component values produces positive results, circuit taken from;

• Paul Horowitz, Winfield Hill, The Art of Electronics, page 182, Cambridge University Press, 1989 ISBN 0521370957.

This paper,

• Wang et al, "A Comprehensive Study on Current Source Circuits", IFMBE Proceedings, Vol 17, pp213-216, Published by Springer, 2007 ISBN 3540738401.

shows a Howland circuit in conjunction with a GIC to cancel the Howland circuits capacitance. If the Howland circuit were a NIC presumably it would be able to cancel it itself internally without the need for all this extra circuitry. On that basis I am going to remove Howland (and Deboo) as examples, at least pending some refs, but I might use the Wang paper as an example ref for load cancelling applications. SpinningSpark 20:00, 27 February 2009 (UTC)

The circuit on Fig. 4.13 (The Art of Electronics, page 182) represents the first version of Howland current source (pump) or, if we exclude the input voltage source and the load, a Howland voltage-to-current converter. It consists of four ingredients: an input voltage source V_IN, a negative impedance converter INIC (R1 = R4 = R3 = R and the op-amp), a "positive" resistor R2 = R and a load. The voltage source V_IN and the INIC constitute a voltage source with negative internal resistance -R that is connected in parallel to the positive resistor R2 and the load. The role of the positive resistance R of the resistor R2 is to "neutralize" the negative internal resistance -R of the source. As a result, the final source has an infinite internal resistance and behaves as a constant current source.

The second version of Howland current source (see Fig. 1 of MAXIM's AN1155) consists of an input voltage source V_IN, a positive resistor R, a load and a negative impedance converter INIC (R1 = R2 = R3 = R and the op-amp). The input voltage source and the resistor R constitute an imperfect current source with positive internal resistance R that is connected in parallel to the negative resistor INIC and the load. The role of the negative resistance -R is to neutralize the positive internal resistance R of the source. As a result, the load is driven again by a constant current source with infinite internal resistance. Well, let's include some algebra to be more cogent.

The imperfect current source produces a current I_L = (V_IN - V_L)/R = V_IN/R - V_L/R. As you can see, it differs from the ideal result I_L = V_IN/R by the term V_L/R. It is more than obvious that we may compensate this error by adding the same term; then, I_L = V_IN/R - V_L/R + V_L/R = V_IN/R. That means to inject an additional "helping" current I_H = V_L/R that is proportional to the load voltage. What is this circuit that can produce such a current I_H? Of course, it is a voltage driven negative resistor with resistance -R; it is a negative impedance converter with current inversion (INIC) that is connected in parallel to the load.

The generalized version is a combination between the two ones where the output current is proportional to the difference between two input voltages. As a conclusion, Howland voltage-to-current converter consists of two connected in parallel resistors with equivalent but opposite (positive and negative) resistances; Howland voltage-to-current converter = INIC + resistor. The "neutralization" between them produces an infinite resistance and, as a result, a constant current. The circuit is stable since the positive load resistance remains after the "neutralization" (another wisdom: in order to have stability, the negative resistance has to dominate over the positive resistance in a voltage-controlled negative resistor and the positive resistance has to dominate over the negative resistance in a current-controlled negative resistor).

Deboo integrator (see again Fig. 1 of MAXIM's AN1155) is just a Howland voltage-to-current converter driving a capacitive load; Deboo integrator = Howland voltage-to-current converter + capacitor. It has two advantages over the dual inverting integrator: it is a non-inverting circuit and the capacitor is grounded. But it has two disadvantages as well: it requires an op-amp with differential input and it has a bigger error depending on the resistor tolerances (here, the op-amp does not monitor the result of the compensation as it monitors the virtual ground at the inverting circuit).

It is interesting that although there was nothing new in a Deboo integrator (actually, it was just a Howland pump driving a capacitor) Deboo was not aware of the Howland current source when he invented his integrator. I found out this fact in a personal correspondence between me and Deboo a year ago (Deboo was impressed by my comments to an EDN article about his famous circuit and emailed me). By the way, then I also exchanged interesting thoughts with Deboo about the unique feature of negative feedback to reverse the causality in circuits (to swap circuit inputs and outputs). For example, the negative inductance circuit is based on this idea.

Today, I found an extremely interesting source about the invention of the Howland circuit. Although it is nameless, it seems it is written by the very Howland. Circuit-fantasist (talk) 16:46, 1 March 2009 (UTC)

Negative resistance materials

The article states that "Negative resistors are theoretical and do not exist as a discrete component". This is true for standard conductiving and semiconducting materials. However, some amorphous materials and conductive polymers do exibit negative resistance as an intrinsic characteristic. In such materials, conduction depends on localized states, hopping, etc. In fact, IIRC, Neville Mott won an Nobel prize for figuring out how such things work.68.90.51.149 (talk) 17:00, 12 June 2009 (UTC)

Surely you're referring to the same type of negative resistance behavior seen in tunnel diodes, which is already given as an example in the introductory paragraph. Due to conservation of energy, negative resistance can only exist in a small region of any discrete device's operating region, and that is especially true for naturally occurring materials. Does the i–v curve of the materials you're discussing exhibit negative resistance everywhere, and, if it does, does it also intersect the origin (i.e., is it an active device?). Surely it intersects the origin (passive device), has a positive slope at the origin (positive resistance), and has negative resistance away from the origin (negative resistance region, like a tunnel diode), and then goes back to having positive resistance far from the origin (again, like a tunnel diode). If so, then the example at the end of the introductory paragraph should be expanded to include other materials... but certainly the intro paragraph shouldn't be changed to say that true "negative resistors" exist in nature. —TedPavlic (talk) 17:11, 12 June 2009 (UTC)

Much conduction in amorphous semiconductors occurs by localized tunneling and phonon-assisted hopping between localized states. Really stretching the analogy-- a little like a whole bunch of really-small tunnel diodes. I.e., negative conductivity is a collective property of the material and not some engineered barrier effect. Similarly, such materials exibit "switching", even though they are not devices per se . Some conductive polymers show similar behavior.Pproctor (talk) 01:50, 14 June 2009 (UTC)

Right -- that seems like what you'd expect, and the $i$--$v$ curves would still only exhibit negative resistance within a region. Hence, it seems most appropriate to change the claim about tunnel diodes at the end of the introductory paragraph to be more inclusive. —TedPavlic (talk) 14:13, 14 June 2009 (UTC)

Actually, the defining condition for breach of conservation of energy is, as the article says, if and only if the curve enters an even quadrant, not intersecting the origin. Having a negative slope and intersecting the origin are, together, sufficient, but not necesssary conditions, and either one alone is neither necessary nor sufficient. SpinningSpark 17:29, 12 June 2009 (UTC)

That's bikeshedding. Counter examples are pathological in the context of this discussion. The question is how (and if) the article should change to accommodate facts about amorphous materials and conductive polymers. I feel that if anything needs to change, the final sentence of the introductory paragraph needs to be massaged to allow more than just special diodes. Otherwise, things are fine. —TedPavlic (talk) 17:40, 12 June 2009 (UTC)

No need for the insults. SpinningSpark 17:57, 12 June 2009 (UTC)

Fluorescent Bulb

Shouldn't there be a mention of ballasts and their role they play in battling the negative resistance in fluorescent bulbs? 192.91.172.42 (talk) 23:38, 11 August 2009 (UTC)

Interesting... Would you like to discuss the topic here? Circuit-fantasist (talk) 11:36, 13 August 2009 (UTC)

Not just Fluorescent, but other discharge lamps act as negative resistances, e.g. Mercury-vapor lamp links here. Tetrodes also exhibit negative resistance over part of their operating range, which was a design consideration in amplifier applications, and the basis of dynatron oscillator operation.--Theodore Kloba (talk) 16:40, 21 October 2011 (UTC)

Resuming editing

I have resumed editing as the page is poor. I will back up every my edit with a comprehensive summary. If you edit or remove my inserts, I will advance my arguments on the talk page and will invite you to discuss the topic. If you do not react, I will revert to the previous state. I will consider ungrounded and uncommented edits as vandalism and will revert as well. If it occurs again, I will notify administrators. Circuit-fantasist (talk) 17:39, 6 October 2009 (UTC)

Good to see such respect for wiki policies on assuming good faith and owing articles -- Timberframe (talk) 17:47, 6 October 2009 (UTC)

No-one is allowed their own definition of vandalism. WP:VAND is clear: " made in a deliberate attempt to compromise the integrity of Misplaced Pages". This definitely does not come under the changes you have listed above, though leaving edit summaries and discussing edits is strongly encouraged. —BillC  18:23, 6 October 2009 (UTC)

Sorry for my sharp tone above; as I can see, it is not intended for you. I would like only to warn that I will fight for truth and will not allow someone to play fast and loose with this page any more. Thank you for response. Circuit-fantasist (talk) 20:22, 6 October 2009 (UTC)

Resuming discussion

Spinningspark, you know that all I want is to discuss, to reveal the truth about these odd, strange, mystic and never explained circuits and components... And I have been trying (many times) to involve (well-meaning) wikipedians related to this page in such a creative discussion... And should I remember all the questions that I have put under discussion...and what you have (not) done to second me? Instead, you have allowed the truth about the unique phenomenon to be obliterated and the page to be disfigured... The result of this passive contemplation is this mutilated page where there is no structure, no basic ideas, no human explanations, no ... Well, let's resume discussion; I am ready to discuss again...and again...and again... What to begin with? Maybe, with definition: What negative impedance (resistance) is?Circuit-fantasist (talk) 21:27, 6 October 2009 (UTC)

No, you should begin with your sources that back up your statements. Reliable ones, not websites or Wikibooks you have written yourself. I have two immediate objections to your edits to the lede. (1) There is no such thing as a one-port negative resistance circuit. (2) Your use of "true" negative resistance to mean a circuit that produces an I-V curve intersecting the origin is at odds with everyone else, where the meaning is a one-port component that does this - which of course does not exist. Please provide reliable sources for these proposed additions. And please do not again post a detailed description of your theories and views, we can read them in the talk page archive if we really want to know. Instead post links to reliable sources that describe them, if there are any. SpinningSpark 00:30, 7 October 2009 (UTC)

Definition: What negative resistance is?

The first sentence says: "Negative resistance is a property of some electric circuits where an increase in the current entering a port, results in a decreased voltage across the same port." Reading this ubiquitous definition of negative resistance phenomenon I would like to say some remarks:

• It is obvious that elements exhibiting negative resistance property (tunnel diode, SCR, UJT) are 2-terminal (one-port) ones. Also, circuits exhibiting negative resistance property (VNIC and INIC op-amp circuits, SCR-, UJT- and Lambda simulated transistor circuits) are 2-terminal (one-port) devices.
• Current can not only enter the port; it can exit the port as well. So the sentence "current flows through the port" encompasses the both cases.

• To say "...an increase in the current results in a decreased voltage across the NR..." is suitable only in the case of differential negative resistance elements and circuits; but it is confusing and misleading in the case of true negative resistance circuits. The problem is that when people meet words as "increase" and "decrease" applied to current and voltage they usually think of these electrical attributes as quantities with absolute values, not as quantities with signs. An example: imagine that a 12 volt battery is grounded with the positive terminal. If you say that the battery has decreased its voltage, e.g. by 2 volts, people will think of this battery as a 10 volt source not as a 14 volt one. Another example: imagine 1.5 A current flows in some circuit; then say that the current has decreased with .5 A and ask people what the current is. What will people answer? "2 A" or "1 A"? Be sure, no matter whether the current enters or exits the circuit they will answer "1 A" (even in the case of "negative" current) as people usually think in terms of current magnitudes. So, thinking in this way (and especially if they do not see the picture on the right) and reading the ubiquitous definition, people will think of a true negative resistor as of a positive one!

The considerations above are more than obvious and are based on common sense. Don't you think they do not need to be backed up with any citations? Taking account of these remarks I suggest changing the first sentence as follows:

"Negative resistance is a property of some one-port electric circuits where an increase in the current flowing through the circuit, results in a decreased voltage across it."

and to add an explanatory disambiguating footnote:

"In this definition, current and voltage are considered as quantities with signs (not as quantities with absolute values)."

--Circuit-fantasist (talk) 21:29, 7 October 2009 (UTC)

Use of the term "one-port" for these circuits is dubious, as in reality there must be at least one other port which supplies the energy. Even for the tunnel diode, it only appears negative resistance as a small-signal equivalent circuit from which the dc bias has been discounted. So yes, I do think that sources are needed describing negative resistance circuits in this way before it can be used in the article. If there are none, we should not make up terminology.

I agree with you. Really, these circuits are typically but not obligatory one-port networks. They exhibit negative resistance at one port but they can have also another or more ports. Deboo integrator is a good example of such a configuration; power supply port not so much. Thanks, Circuit-fantasist (talk) 04:48, 11 October 2009 (UTC)

I agree with your point about absolute and signed quantities. However, this can be dealt with by a simple addition, for instance, changing "decreased voltage" to "a decrease in the signed voltage". There is no need to make a major issue of this, certainly not in the lede paragraphs which should be kept simple, our readers are not idiots. SpinningSpark 15:18, 8 October 2009 (UTC)

Spinningspark, the most of our readers are not professionals. For example, Bob Pease never will write "negative resistance" in the Google window (although, I'm absolutely sure, he does not really know what negative resistance actually is). Instead, not as famous but curious people as pupils, students, technicians and hobbyists will want to know what it is and the introductory definition is the first explanation that they will meet. So, we have to consider very well the lede paragraph.

In the very beginning, we want to cover the two kinds of negative resistances (true and differential one) with one common definition. But the big problem is that they are completely different (a true negative resistor is a dynamic source while a differential negative resistor is a dynamic resistor). Maybe only the negative slope of their IV curves is the only relationship between them... Circuit-fantasist (talk) 19:32, 11 October 2009 (UTC)

I don't agree with your comments C-F. There are established methods for analyzing and describing electronic circuits. You choose to devise your own. These novel musings don't belong here. I'm sure Bob Pease knows a lot more about negative resistance than you do and I suspect there is some history between you and Bob. I wish you would stop editing perfectly well written articles and reducing them to gibberish. Your command of the English language is marginal and your understanding of electronics is severely lacking.Zen-in (talk) 05:44, 13 October 2009 (UTC)

Negative differential resistance vs negative differential conductance

I think this page is a bit confusing. The primary examples (tunnel and Gunn) diodes are poor examples of NDR: they don't even have a single-valued V(I) curve, and therefore are not monostable in a current bias configuration, so it's hard to argue that there is negative dV/dI (differential resistance) because dV/dI is multivalued: for a set current which has multivalued voltage, the voltage curve crosses at three places: twice with positive slope, and only once with negative. The sentence "Increasing the current causes an decrease in the voltage" is a misleading way to describe these N-shaped curves.

On the other hand, the current is a single-valued function of voltage, and tunnel diodes have obvious negative differential conductance (NDC). In a voltage-bias measurement, this is unambiguous: increasing the voltage causes a decrease in the current.

I realize that the phrase "Negative differential resistance" is used much more frequently in the literature of NDC, but it's worth pointing out at least somewhere on wikipedia that NDC is the correct term. 142.103.140.130 (talk) 03:44, 7 May 2010 (UTC)

Your thoughts are very interesting and valuable, especially about the two dual terms (NDR and NDC). I completely second your opinion. I only regret that I have not taken note of your insertion earlier. Circuit dreamer (talk, contribs, email) 14:58, 24 December 2010 (UTC)

S-shaped versus N-shaped negative resistors

We should not simply say in the negative resistance definition that "an increase in the current entering a port results in a decreased voltage across the same port" since this definition is valid only for S-shaped negative resistors (e.g., a neon lamp, a negative impedance converter with voltage inversion VNIC, etc.) Only in this case, by changing the current through the resistor as an input quantity and measuring the voltage across it as an output quantity, the S-shaped negative resistor will operate in a linear mode (see linear VNIC). Its IV curve will be single-valued (see the section above) and we can observe a negative resistance region in the middle of the curve. If we try to drive an N-shaped negative resistor (e.g., a tunnel diode, a negative impedance converter with current inversion INIC, etc.) in this way, its IV curve will be multivalued (see again the section above). It will act as a bistable circuit with hysteresis (Schmitt trigger, latch); the voltage will "jump" and we will not observe any negative resistance region somewhere on its IV curve (see bistable INIC). Similarly, we should not drive an S-shaped negative resistor (e.g., a neon lamp, VNIC, etc.) by voltage if we want to see a negative resistance region on its IV curve.

So, the definition has to be more general. It should not say what is an input and what is an output (the causality). It has only to say that "current through and voltage across the same port change in opposite directions" when we vary the one of the quantities (the independent quantity) and measure the other (dependent quantity). In this way, it comprises both the S- and N-shaped negative resistors.

The two pictures represent the two kinds of negative resistors (an S- and an N-shaped one). So, the definitions in captions have to be more specific to show that for a neon lamp having S-shaped negative differential resistance the current is an input and for a tunnel diode having N-shaped negative differential resistance the voltage is an input.

So, the problem of the old article version was that the definition in the beginning of the lede has not matched the negative resistor in the figure. It has described the behavior of an S-shaped negative resistor ("an increase in the current entering a port results in a decreased voltage across the same port") but the figure has represented an N-shaped negative resistor (a tunnel diode). BTW it is a very interesting and very indicative fact that an anonymous visitor but not a reputable wikipedian has noted this discrepancy... Circuit dreamer (talk, contribs, email) 13:12, 24 December 2010 (UTC)

The difference is only in the way the graphs are presented, the axes are interchanged, not in any real difference in the I-V relationship. SpinningSpark 13:20, 24 December 2010 (UTC)

You have not taken into consideration that the whole IV curve of a negative resistor consists of three regions - one middle part representing negative resistance and two end parts representing "positive" resistance. Although the middle (negative resistance) parts of the two kinds of negative resistors look the same, there is a very real difference between them: you cannot drive an S-shaped negative resistor by voltage and an N-shaped negative resistor by current if you want to observe negative resistance. Circuit dreamer (talk, contribs, email) 14:10, 24 December 2010 (UTC)

Edits to the lead

I've reverted this edit, as I think it injects far too much wrongness to be worth editing. In particular:

• Negative differential resistance doesn't involve "energy addition"
• It introduces an unnecessary confusion by discussing negative conductance. Resistance and conductance don't imply causality (i.e. whether voltage causes current or vice versa)
• We would need a source for "circuits with negative resistance are current-driven"
• Even if this material were all correct, it is now more detailed than the article body, which is inappropriate for the lead. If we can make some of these additions sensible, then they should be moved to the relevant sections.
• Others have already expressed their opinions on the diagrams and captions
• Bearden is not in any way to be used as a reference!

Oli Filth 00:50, 26 December 2010 (UTC)

You have preferred to restore the poor, misleading and even wrong lede (see the discussions above) instead to improve it (if there was such a need). In addition, as usual, you have not forgotten to make fun of my creation ("...it injects far too much wrongness to be worth editing...")...

• A negative differential resistors does involve "energy addition" like any active (in the sense of amplification) element (a tube, a transistor, etc.) and this is the idea of any tunnel, Gunn, etc., diode amplifier. The only difference is that it is a 2-terminal active element. I recommend to you to read the Amplification section of the old negative differential resistance page (that you have redirected) to see how a NDC amplifier works.

• Obviously, you have not carefully read the discussions above about NDR and NDC. Have you heard about SNDC and SNDR devices? Do you know that there is a Misplaced Pages article about NDC? Negative conductance helps us to distinguish N-shaped from S-shaped negative resistors. There is causality in all these devices: we have to vary the current as an input quantity in an S-shaped negative resistor and the voltage in an N-shaped negative resistor. If we do the opposite, these devices will not act as negative resistors; they will act as bistable circuits with hysteresis (Schmitt triggers).

• About "circuits with negative resistance are current-driven"... Of course, it is obvious that I have used here "negative resistance" in the narrow sense of the word (as a dual of "negative conductance"). How do I distinguish the two kinds of elements as there is no a common word for the both?

• For now, I have inserted this essential data into the lede. How do I insert something sensible in the mess below? The article body needs reorganization, structuring...

• Diagrams and captions illustrate exactly the lede; they are closely related to the lede.

• Bearden's picture is very impressive and informative. It reveals the basic idea of negative resistance phenomenon; so, it is closely related to the lede.

Circuit dreamer (talk, contribs, email) 07:17, 26 December 2010 (UTC)

The material you propose is the wrong place (see WP:LEAD) and makes a rather simple concept unnecessarily obtuse. As Oli Filth points out, Bearden should not be used as a source: see The Final Secret of Free Energy. Johnuniq (talk) 09:04, 26 December 2010 (UTC)

Well, I see... but we have to start somehow. Don't you think it is better to have, as a starting point, a detailed but informative lede instead a short but misleading one? I intend to (re)structure the article body according to the classification described in the lede. Would you join this initiative? Circuit dreamer (talk, contribs, email) 10:17, 26 December 2010 (UTC)

BTW negative resistance (impedance) phenomenon is not at all "simple concept" for people. Actually it is extremely simple but, for some reason or other, people do not (want to) realize it. If you not believe me, browse through the discussions above and through the old archived discussions... Circuit dreamer (talk, contribs, email) 10:51, 26 December 2010 (UTC)

I will use my usual response: if you can find a reputable source that makes this distinction between negative resistance and negative conductance, then we can discuss that further. Also, if you can point out what aspects of the original lead are "misleading", then I will gladly discuss that too. Oli Filth 11:13, 26 December 2010 (UTC)

Have you read the discussions above? Or you just want to waste my time? Do not make me repeat obvious, simple and clear truths again and again and again... Well, we can use with the same success "S-shaped" and "N-shaped" instead "negative resistance" and "negative conductance". What do you think about this classification? Circuit dreamer (talk, contribs, email) 12:53, 26 December 2010 (UTC)

Is there a reputable source that makes this classification? Or at least, a source that uses this classification to come to the same conclusions as you? Oli Filth 11:02, 27 December 2010 (UTC)

Let's first build the classification; then we can find sources that second it (if there is such a need). Here is my proposal. Circuit dreamer (talk, contribs, email) 17:47, 28 December 2010 (UTC)

NEGATIVE RESISTORS

ABSOLUTE NEGATIVE RESISTORS (dynamic sources)

S-shaped absolute negative resistors (voltage inversion negative impedance converter VNIC)

Current-driven S-shaped absolute negative resistors (VNIC in linear mode acting as a negative resistor)

Voltage-driven S-shaped absolute negative resistors (VNIC in bistable mode acting as a latch)

N-shaped absolute negative resistors (current inversion negative impedance converter INIC)

Voltage-driven N-shaped absolute negative resistors (INIC in linear mode acting as a negative resistor, Howland current source, Deboo integrator)

Current-driven N-shaped absolute negative resistors (INIC in bistable mode acting as a latch)

NEGATIVE DIFFERENTIAL RESISTORS (dynamic resistors)

S-shaped negative differential resistors (neon lamp, thyristor)

Current-driven S-shaped negative differential resistors (neon lamp supplied through a ballast resistor)

Voltage-driven S-shaped negative differential resistors (neon lamp relaxation generator)

N-shaped negative differential resistors (tunnel diode, Gunn diode, unijunction transistor)

Current-driven N-shaped negative differential resistors (tunnel diode latch)

Voltage-driven N-shaped negative differential resistors (tunnel diode amplifier)

I intend to base the article on this classification. Circuit dreamer (talk, contribs, email) 17:50, 28 December 2010 (UTC)

I think Circuit-Dreamer has a valid point (which I apologise for having overlooked in a previous exchange above). Both cases have a negative slope of the I-V curve, but there is a difference in the way in which the device is driven/biased into the negative region. A tunnel diode must be voltage driven in order to guarantee that the bias point gets past the first I-V maximum. Neon signs etc must be a high-impedance source (ie current source) since the first peak is a peak in voltage, not in current. This does not, however, detract from the need to provide sources for what we write. Circuit dreamer is entirely wrong to state "Let's first build the classification; then we can find sources that second it". It is completely the other way round, find sources first and then write from the sources. I would say that even the terminology N-shaped and S-shaped needs sourcing. SpinningSpark 20:17, 29 December 2010 (UTC)

There is NO negative resistance, only "negative differential resistance" (NDR)

I am surprised this article came this far with such a misleading and incorrect heading. People are entitled to their ideas and opinions but not to their facts as someone much wiser than me stated. Sometimes the enthusiasm to contribute here seems to go inversely propotional to the qualifications. There is no negative resistance in the universe and there is a very simple reason for it: It is against the laws of theromdynamics. Such a component would be generating energy out of thin air! One can only talk about negative differential resistance and in fact everything told in the article describes NDRs. It is the slope that may go negative, not the ratio of voltage to current. I am very interested in an example of an "absolute negative resistor". —Preceding unsigned comment added by 12.229.112.98 (talk) 19:44, 16 March 2011 (UTC)

Indeed, absolute negative resistors do not exist (for now) as elements. Some 1-port electronic circuits (including the power supply) act as absolute negative "resistors". They add energy to circuits in the same manner as the equivalent resistors subtract energy from circuits. For example, a series connected VNIC adds voltage that is proportional to the current through the port while a parallel connected INIC adds current that is proportional to the voltage across the port. For comparison, the series connected ohmic resistor with the same resistance would subtract voltage that is proportional to the current through it; the parallel connected equivalent resistor would subtract current that is proportional to the voltage across it. So, the true negative resistor is actually not a resistor; it is a dynamic source. In contrast, the differential negative resistor is really a resistor; it is a dynamic resistor. It acts as a 2-terminal active (regulating) element that controls the energy of an additional source (a power supply). The combination of the differential negative resistor and the source acts as a true negative resistor that adds energy to the circuit. Circuit dreamer (talk, contribs, email) 22:12, 16 March 2011 (UTC)

Would it be rude of me to suggest you keep your unique sense of sementics out of a public platform like this? Especially now that we established that there are no negative resistors, which is boldly the title of the article. A power supply is called a power supply and dynamic load is called a dynamic load, these are the terms and terminologies used by the people who actually practice the art. There is no component that is negative resisotr. I am sure there are many other forums where you can freely disseminate your unique interperatations and definitions but a general encylopedia is not a sutiable place for it. Looking at the discussions above, it seem plenty of folks have already tried to give you a hint, so it is a mystery why you would still insist on spreading false and incorrect information. —Preceding unsigned comment added by 12.229.112.98 (talk) 22:25, 16 March 2011 (UTC)

There is nothing unique in these sentences; they just say the simple truth about the negative resistance. There is not a true negative resistor implemented as a 2-terminal component but there are electronic circuits (negative impedance converters) acting as true negative resistors (note I have said "they act", not "they are"). Circuit dreamer (talk, contribs, email) 23:20, 16 March 2011 (UTC)

Hi 12! Thanks for your comments. I haven't had time to check this article lately, but I agree with your assessment of the situation: whereas circuitry with an inexhaustible power input can be rigged up to act as an "absolute" negative resistor would, in practice we would use other names for such things. Please edit the article or comment on specific items if you see something that should be fixed. Johnuniq (talk) 01:42, 17 March 2011 (UTC)

Here are some sources believing there are negative resistors and naming the corresponding circuits "negative resistors":

• Negative Resistor Cancels Op Amp Load - "If your resistive load is "R"Ω and you connect in parallel with it a negative resistor of "-R"Ω..."
• Negative-resistance circuits - "Negative resistors can be implemented by using amplifiers in positive-feedback configuration."
• Negative Resistor - Physics 123 demo with Paul Horowitz
• Negative resistance - "A negative resistor would need to suck in heat and turn it to electrical energy."
• How to build a negative resistor??

Circuit dreamer (talk, contribs, email) 12:26, 12 April 2011 (UTC)

Ah, now there are claims of negative resistance again. Sources "believe"! Now we are in the sipiritual realm finally. Sounds like the Big Foot or Yeti. This farce needs to stop, it is degrading to Misplaced Pages. There is no negative resistance in the universe. It is non-physical, against all rules of thermodynamics and conservation. Negative differential resistance, which this poorly trained editor does not seem to understand, is a totally different phenomena. He is able to list the above outrageously titled articles from hobby magazines and trade journals, only because none are peer reviewed serious reference journals. Is it any wonder there is not a single IEEE reference? This is really shameful. —Preceding unsigned comment added by 173.77.162.40 (talk) 05:56, 7 May 2011 (UTC)

I think the reason for this confusion with terminology is because of misuse of the word differential. An emitter coupled pair is called a differential amplifier because it has inputs that drive a given output in opposite directions. The term you should be using instead of differential is incremental. Electronic circuits have a DC or steady-state behavior and a transient or incremental behavior. Incremental analysis of a circuit takes into account quickly changing behavior. For example there is no DC current flow through a capacitor. But incrementally capacitors do store and release charge. All the dynamic behavior we see in circuits is incremental phenomena. Negative resistance is an incremental effect. It would be correct to use the term incremental negative resistance but the term incremental is always implied when discussing behavior that is not steady-state (DC). Zen-in (talk) 14:20, 11 May 2011 (UTC)

The problem is not if NDR is named differential or incremental; both the words serve well to denote this phenomenon. The problem is that people (including you) do not understand what actually the differential and absolute negative resistances (resistors) are. They do not see the essential difference between them (that NDR is just a positive resistor while the true negative resistor is just a source); as a result, they even do not suppose the absolute negative resistance can exist! Imagine they accept that there are sources but they cannot accept that there are negative resistors because they do not know (because of you and the likes of you) the simple truth that negative resistors are nothing else than sources! The only difference between them and the ordinary sources is that negative resistors are dynamic sources (whose voltage is proportional to the current through them or whose current is proportional to the voltage across them) while the ordinary sources are constant sources (constant voltage or constant current).

"Negative resistance is an incremental effect" is not true (if you mean true negative resistance). If you suppose its IV curve passes through the origin of the coordinate system (the usual case), then the negative resistance is not differential one; it is just a bare static resistance (exactly as ohmic resistance but with a negative slope). I.e., in this case, the differential and the static (chordal) resistance are the same. Only in the case when the IV curve does not pass through the origin (it is possible for true negative resistance as well!) we have two kinds of resistances - differential and static. Circuit dreamer (talk, contribs, email) 17:02, 11 May 2011 (UTC)

Sure, but it's still unhelpful for this article. Is there a suitable source to provide guidance regarding how much coverage would be due for "absolute" negative resistance in this article (as opposed to NDR which is what people mean 99% of the time)? Johnuniq (talk) 04:58, 12 May 2011 (UTC)

There are a lot of resources about negative impedance converters, Howland current pumps, Deboo integrators, load cancellers and maybe other circuits acting as true negative resistors (additional sources that add proportional voltage or current to the main source). Circuit dreamer (talk, contribs, email) 05:38, 12 May 2011 (UTC)

"...as true negative resistors"? There seems to be a mental block of some sorts involved, maybe an obsession. Neither belong to these pages. There is no such thing as a negative resistor. There is no such thing as a negative resistors or "acting like one". That would be called a source. This article is a candidate for deletion. Amazing it has come this far. Murat (talk) 03:37, 27 May 2011 (UTC)

I marvel over how stupid someone has to be to not understand the so simple but genius idea - connecting a varying source with voltage -2V_R in series to a resistor R with voltage drop V_R gives a total voltage -V_R! The combination of the two elements behaves as an element producing voltage proportional to the current (V_R = -R.I) while the humble resistor R "produces" voltage drop proportional to the current (V_R = R.I).

How do we name this element? Of course, "negative resistor"! But this is a figurative name since our creation is actually not a resistor; it is a source. But it is not an ordinary constant voltage source; it is a proportional to the current voltage source...

How do we use it? If we connect it in series to a "positive" resistor with resistance R1 > R, our negative resistor will "eat" only a part R from the whole R1; the result will be positive resistance R_tot = R1 - R > 0. Then, if we connect it to a resistor with resistance R1 = R, the negative resistor will absorb it entirely and the result will be zero resistance R_tot = R1 - R = 0. Finally, if we connect it to a resistor with resistance R1 < R, the result will be smaller total negative resistance R_tot = R1 - R < 0... and you can only guess what will happen in this circuit... Circuit dreamer (talk, contribs, email) 18:05, 27 May 2011 (UTC)

You are skirting too close to an attack in the above (yes, you didn't actually call anyone stupid, but your meaning is clear). I do not see anyone here who fails to understand the topic, and your explanations of why the term "negative resistance" is appropriate are not needed or relevant. What is needed, are reliable sources to justify text in the article. Johnuniq (talk) 04:02, 28 May 2011 (UTC)

A source for a battery connected in series to a resistor? Here is one. Circuit dreamer (talk, contribs, email) 04:51, 28 May 2011 (UTC)

I think you have just ruled out any chance of being taken seriously. By all means strike the above comment as a misplaced joke if you like, but taking it at face value, Misplaced Pages is not included at WP:RS, and the issue concerns using the name "negative resistance" to refer to what most people would call a source. Johnuniq (talk) 05:20, 28 May 2011 (UTC)

Sorry for joking... The problem is that this device is not simply a source; it is a very special kind of source; it is a proportional source. It can be a voltage source that changes its voltage proportionally to the current flowing through it or it can be also a current source that changes its current proportionally to the voltage across it. Due to this proportionality such a device can compensate a proportional voltage drop across or a proportional current through an equivalent resistor. Also, they are not independent sources; they are auxiliary sources connected in circuits supplied by main sources (they begin producing voltage/current when a current begins flowing through them or a voltage is applied across them).

So, we have somehow to draw attention to this proportionality by choosing an appropriate name for this so odd source. Of course, we may use some descriptive names as two-terminal current-controlled voltage source (two-terminal voltage-controlled current source) or one-port current-to-voltage converter (one-port voltage-to-current converter), etc. But if we note that it has an inverse to a resistor behavior, we can name it figuratively negative resistor. And to distinguish it from NDR, we have to add some word as true, absolute, etc., before it. Then we can say that the group of negative resistors consists of two subgroups - true negative resistors and differential negative resistors, and we have to structure the page according to this taxonomy. BTW all these names are already in use:

"negative resistance" - 374,000 results

"true negative resistance" - 3,600 results
"absolute negative resistance" - 5,200 results

"differential negative resistance" - 25,500 results

Circuit dreamer (talk, contribs, email) 16:07, 28 May 2011 (UTC)

About 89,800,000 results for Black Magic Zen-in (talk) 04:48, 2 June 2011 (UTC)

Unfortunately, my browser shows only 14,000,100:( Circuit dreamer (talk, contribs, email) 07:14, 2 June 2011 (UTC)

First, you should read Google result counts are a meaningless metric, so you will understand that, well, Google counts are almost meaningless.

Next, you should read some of the links.

For example, when I searched for "negative resistance", the first hit was a Misplaced Pages page. Not a reliable source.

The second hit was Negative Resistance oscillators. Is it reliable? Probably not, but the more important point is that it says: "For this reason, although it is conventional to call this effect ‘negative resistance’ it should more strictly be called Negative Differential Resistance or Negative Differential Conductance. "

I'm not going to look further. Your own links are disproving your point.--SPhilbrickT 21:19, 11 August 2011 (UTC)

When you make a list of things to support your point, and the first two do not support your point, I'm going to stop reading the list, and put the burden on you. Which links support your point?--SPhilbrickT 11:55, 12 August 2011 (UTC)

After 5 years, it is time to reorganize the page...

I am hopeful that after all the discussions about the nature of negative resistance that I started in 2006 and finished yesterday, there are no people that do not adopt the simple truths below about negative resistance phenomenon:

• There is nothing mystic in negative resistance phenomenon and in negative resistors; they are simple devices that can be explained by means of common sense and intuition.
• The general property of negative resistors is their ability to add (their own or else's) energy into circuits.
• True negative resistors add their own energy while differential negative resistors add else's (external) energy.
• True negative resistors exist as they are nothing else than sources that do not violate thermodynamics laws.
• These "sources" are not simple sources; they are proportional sources (voltage sources changing its voltage proportionally to the current flowing through them or current sources changing its current proportionally to the voltage across them).
• Due to this proportionality true negative resistors can compensate proportional voltage drops across or proportional currents through equivalent "positive" resistors.
• True negative resistors are auxiliary sources connected in circuits supplied by main sources; they begin producing voltage when the main source begins passing a current through them or they begin producing a current when the main source applies a voltage across them.
• Differential negative resistors are nonlinear positive resistors with extremely varying resistance in the negative resistance region.
• They are not used independently; they are used in a combination with a power source.
• This combination forms a true negative resistor... (to be continued)...

IMO five years are enough to realize these simple truths and already it is time to tidy up the page. Spinningspark? Circuit dreamer (talk, contribs, email) 10:24, 29 May 2011 (UTC)

The dispute does not concern whether the ratio of voltage to current can ever be negative. Instead, the issue concerns the encyclopedic value of an exposition on a "true negative resistor": Does the topic satisfy WP:DUE? Do the sources satisfy WP:SECONDARY? Johnuniq (talk) 10:37, 29 May 2011 (UTC)

I think I have said through these years a little something more than "whether the ratio of voltage to current can ever be negative":) As for the name, it is widely used (3700 Google results). As for the exposition on a "true negative resistor", I will work out it in the page about negative impedance converter (the most popular circuits acting as true negative resistors). I have explained in details these circuits in three Wikibooks modules - Negative impedance, VNIC and INIC. Circuit dreamer (talk, contribs, email) 10:54, 29 May 2011 (UTC)

Merge from negative differential conductivity

I've proposed that content from Negative differential conductivity (edit | talk | history | protect | delete | links | watch | logs | views) be merged into this article, and that article redirected here. Please indicate whether you think this is a good or bad idea below.

By all means add a short rationale; that said, extended discussion should probably go in its own section (I've added one below). Litmus test is, if you're responding to someone else's comment, putting it in the comments section probably works best. --Christopher Thomas (talk) 06:21, 16 June 2011 (UTC)

Brief statements

• Support merge into negative resistance. The "negative resistance" article has a far clearer explanation of the phenomenon, and I usually see it described as "negative resistance" or "negative impedance" in (US) academic publications, so keeping it here seems to match WP:TITLE best. --Christopher Thomas (talk) 06:21, 16 June 2011 (UTC)
• Support Per CT. The main point is that it is negative resistance, whether this is expresses as (differential) conductance, impedance, or whatever, is somewhat secondary.TR 08:09, 16 June 2011 (UTC)
• Support Xxanthippe (talk) 09:25, 16 June 2011 (UTC).
• Support Resistance is the more common; same idea. Glrx (talk) 13:55, 16 June 2011 (UTC)
• Oppose Ths whole articles is in desperate need of deletion. It basically claims Earth is flat. No need to make it more complicted and spoil other articles. — Preceding unsigned comment added by 12.229.112.98 (talk) 16:32, 17 June 2011 (UTC)
• Support Absolutely. As TR says, "negative differential conductivity" is really just a more technical term for negative resistance. --Chetvorno 21:46, 7 March 2012 (UTC)

Discussion

Comment - With regards to "negative resistance", "differential resistance", etc, I've usually seen this type of measurement referred to as "small signal resistance". When performing AC analysis (at least up here), it's customary to split signals into a large signal DC component (which can assume any bias value), and a separate AC component that is assumed to be small enough for linear approximations of circuit component behavior to hold. Per this article, that can sometimes result in a negative small signal resistance. In papers that give ac analyses, the words "small signal" are usually omitted (mentioned once at the beginning of the analysis to make context clear).

That said, it's possible this is a regional thing. The papers I read are generally from IEEE journals and other North American sources. --Christopher Thomas (talk) 08:36, 16 June 2011 (UTC)

Not true. One will never find an article on "negative resistance" in a proper journal, since it does not exist. Words have been taken out of content. In fact, most of the references are not from respectable peer-reviewed magazines, where writers are careful about their choice of words. I seriously doubt if the above editor actually follows any IEEE journals, it is not reflected in references or in discussion.Murat (talk) 21:09, 18 June 2011 (UTC)

Rather than address the assumptions you're making, I'll just point you over to IEEE's search engine, where "negative resistance" gets upwards of 1500 hits (1000 journal publications, 550 conference publications). Enjoy. --Christopher Thomas (talk) 00:23, 19 June 2011 (UTC)

Negative resistance could be distinguished from negative resistivity/conductivity in the same way that we distinguish resistance from resistivity/conductivity and give them separate articles. Resistivity is a property of materials whilst resistance is a property of devices. However, negative differential conductivity does not really discuss materials, it discusses devices so does not really work as its own article. SpinningSpark 16:49, 16 June 2011 (UTC)

The fact there is a graph that shows the IV curve going straight through the origin continuing into the third quadrant should be grounds for deletion. Various concepts, suchs as NDR, NR circuits, and negative resistance and negativity all jumbled here by an unqualified editor.Murat (talk) 21:13, 18 June 2011 (UTC)

I can't see any "IV curve going straight through the origin continuing into the third quadrant" in this page. Circuit dreamer (talk, contribs, email) 11:52, 23 June 2011 (UTC)

How ingenius! Becasue it has been REMOVED! After a long time defending the integrity of the article and claiming factuality, the un=physical plot has been finally removed. A very small step in the right direction! Murat (talk) 15:42, 2 July 2011 (UTC)

If you mean the picture on the right, it illustrates the operation of an S-shaped true negative resistor (Fig. 7b) in the middle part of its IV curve (in blue). In this region, the IV curve has a negative slope and passes through the origin of the coordinate system. The green line represents the IV curve of the input real current source and the red line represents the IV curve of the internal dynamic voltage source. The multitude of lines gives an impression of line movement (animation). When the input current varies, its green IV curve moves vertically remaining parallel to itself. The internal voltage source varies its voltage and moves its red IV curve horizontally in the according direction so that the intersection (operating) point pictures the blue negative resistance IV curve. As you can see, the negative resistor IV curve lies completely in 2nd and 4th quadrants. The other curves cross the 3th quadrant but they are "positive". I have replaced this "ideal" IV curve with the more practical N- and S-shaped curves of INIC and VNIC. Circuit dreamer (talk, contribs, email) 14:19, 9 July 2011 (UTC)

About the last major edits

I have reconstructed the article according to the dicussions. I have explained what negative resistance actually is, how it is implemented in two versions and how negative resistors operate. I have structured the article according to the idea that there are two kinds of negative resistance circuits (differential and true) that are closely related but yet they are quite different.

I have removed the top picture about resonant tunneling diode as it is too detailed for this place. I have also removed some manifestly promotional external links presenting specific circuit solutions. I have tried to salvage all useful insertions from the previous version. Circuit dreamer (talk, contribs, email) 10:09, 2 July 2011 (UTC)

I think you should self-revert this series of edits and request that you do so right away.

• You have once again inserted whiteboard drawings which have been discussed before. Previous discussions resulted in their removal for their unprofessional look with freehand sketches and stick-men figures.
• Much of the prose is unfathomable, making a simple idea completely obtuse: an example is the opening sentence of the background "Negative resistance can be created in some limited region of resistor IV curve by vigorously changing the resistance or the magnitude of additional voltage."
• While I agree that there are two different things being discussed on this page and they need to be clearly separated, the current article really fails completely in the clarity department.
• The use of the terms "true negative resistance" and "absolute negative resistance" have been opposed on this talk page by about every editor that has commented on the subject and yet they have been inserted in the article "according to discussions" as if everyone now agreed. Just because you have written your views on this page does not mean else everyone agrees.
• "True negative resistor" is even more unacceptable - there is no such component.

I do agree with your removal of the top picture, that really was not very helpful to the reader. I also agree on the need to distinguish negative differential resistance from negative resistance circuits but it needs to be done with standard terminology with reference to good sources, not our own OR. SpinningSpark 13:34, 2 July 2011 (UTC)

It all seems like rather desperate attempts at saving a totally irrelvant article that did not belong here (or anywhere) in the first place. The fact that Misplaced Pages is not exactly a scinetific or engineering reference source or visitied by scientists (here is a good example why) makes these oddities survive here this long I think.

• The name of the article is still the biggest problem with it, and not the only one. It is simply wrong and misleading.
• There is confusuion about "negative resistance", negative differential resistance" and "negative resistance circuits".
• The editor who seems to have been emotionally vested into this creation does not seem to seperate these concepts and uses them interchageably
• Some of the information belongs to a NDR article.
• Some of the rest belong to a "Negative Resistance Circuits" article, though not sure if there is such an obvious need in Wkipedia for it.
• Whatever remains should then be expunged from here and the travesty should end.

Murat (talk) 15:56, 2 July 2011 (UTC)

I support the statement by SpinningSpark: this article has gone off the rails. There is bad writing ("dynamizing the resistance or voltage") and unhelpful OR (NDR and ANR—yes we understand, but the presentation gives a false picture of the real world). Johnuniq (talk) 01:57, 3 July 2011 (UTC)

support revert. I am not troubled by the article title because it is a WP:COMMONNAME. I agree with SpinningSpark's comments. I am not saying the previous version is good; I have trouble with both versions. Although CircuitDreamer is well-meaning, he has gone too far, continues to add his original research, and does not cite to reasonable secondary sources. If I recall correctly, he has been cautioned about those problems in the past. I can overlook some of his awkward English, but not his lack of clarity. Glrx (talk) 03:20, 3 July 2011 (UTC)

support revert. Negative resistance is a commonly accepted term. This was all discussed ad naseum a couple of years ago. Multiple articles on the same subject with different names are not needed. Negative impedance, negative differential resistance, negative differential conductance... have I missed one? Oh yes- negative differential immittance. Whatever happened with the Misplaced Pages Administrator's noticeboard/incident archive 570 where circuit-dreamer was asked to refrain from this very same behavior? Can SpinningSpark explain why circuit-dreamer is able to do whatever he pleases? Zen-in (talk) 04:10, 3 July 2011 (UTC)

Spinningspark, I will answer first to you since you, as an administrator, bear the full responsibility for the final deplorable state of this article. As always, your instant response to my edits predestines what will happen after...

• You have given me an opportunity to self-revert... but to what? To the previous mess where there is no structure, no hierarchy, no classification, no one basic idea, no reasonable explanations of basic implementations and circuit operation, no one picture illustrating the operation...?
• You have said that my "whiteboard drawings have unprofessional look with freehand sketches and stick-men figures". Imagine you have said so much about the form and nothing about the contents! I would like to ask you to answer honestly and responsibly, accordingly to your position in Misplaced Pages, to my simple questions: Have you ever seen such simple, clear and self-explaining illustrations revealing the basic idea (dynamic resistor and dynamic source) behind negative resistance? Pictures that show the motion in operation thus revealing how the negative resistance is created in the middle part of the IV curve? If yes, please give a permission from these sources and place their instead my "whiteboard" pictures; if no, help me to improve them.
• There is no problem with "unfathomable sentences" if only there is a good faith. I am ready to comment them, to explain what I mean and (all together) to improve them. Let's try to do it just now.

In the very beginning, I have tried to show in only one definition the general idea behind the two possible kinds of negative resistances (differential and true): "Negative resistance can be created in some limited region of resistor IV curve by vigorously changing the resistance or the magnitude of additional voltage." Here is what I mean.

I would like to say that negative resistance is created on the base of (by modifying) some positive resistance. Negative resistance cannot exist independently. It cannot exist in the whole operating range; it can exist only in a limited region of the range. Accordingly, negative resistance cannot occupy the whole IV curve; we can create a negative slope (fold up the curve) only in some limited middle part of the whole IV curve of a positive resistor. In the end parts, the resistance is positive; thus the odd "S" or "N" shape.

For this purpose, we have somehow to change the monotonous motion of the operating point (that draws the IV curve) when the input quantity (voltage or current) changes within the negative resistance region; we have to revert its direction. The trick is simple but clever: in the one-variable function I_OUT = V_IN/R (Ohm's law) we begin changing another (second) variable simultaneously with the first one. For example, we can change the very resistance R or we can change the voltage of an additional voltage source connected in series with the resistor. Thus, in this region, we actually have a function of two variables (I_OUT = V_IN/R_IN or I_OUT = (V_IN1 + V_IN2)/R) but we consider it as a function of one variable (we see only the one variable - the input voltage). Thus, we have artificially changed the resistance in this region; we have made dynamic resistance. As a result, the curve changes its slope up to negative but only within the borders in the negative resistance region where we have what (resistance) to change. After the end of the region, the reserve of high resistance (S-shaped curve) or high conductance (N-shaped curve) is depleted and the resistance reaches its minimum (S-shaped curve) or maximum (N-shaped curve). The magic of negative resistance ceases and the ordinary positive resistance establishes in the final part of the IV curve (the negative resistor is saturated). Similar considerations can be written for the first part with positive resistance where the initial resistance is maximum (S-shaped curve) or minimum (N-shaped curve) and the negative resistor is saturated. These end parts of saturation can be seen very well in the IV curves of the op-amp negative impedance converters - INIC (Fig. 5a) and VNIC (Fig. 5b).

So, I have tried to put all the wisdom above in one sentence.

• "The use of the terms "true negative resistance" and "absolute negative resistance" have been opposed..." Please, suggest the right terms then to denote the existing phenomenon. I have tried everything to solve the problem: I have explained that actually there is no true negative resistance exactly as there are no true sources; I have explained what a true negative resistor is (a circuit with power supply); then, I have put "true" in quotes to show that this is a metaphoric name... But what have you done to solve the problem? You continue repeating, "True negative resistor" is even more unacceptable - there is no such component." There is no a component but there is a circuit that can be figuratively named "true negative resistor". See this funny movie of Professor Horowitz (in contrast to wikipedians, he has a sense of humor:) where he has hidden an op-amp NIC supplied by two 9 V batteries in a cardboard box with a label of 10 kΩ to mimic a component (a resistor).

Circuit dreamer (talk, contribs, email) 18:20, 3 July 2011 (UTC)

Please put this on your personal website as it is not suitable for an encyclopedic article. In fact, it is complete nonsense, and you are failing to acknowledge that many of the editors here are totally comfortable with negative numbers, and we understand that a black box can be rigged up to do unusual things. This article will end up being based on traditional and reliable sources, without confusing readers. Johnuniq (talk) 02:36, 4 July 2011 (UTC)

It seems to me we have a run away editor here, devoid of simple common sense and ability to heed to good advice. All of the above plus whats in the logs way before my encounter with this oddity, should have been enough reason to hit the re-start button. I think Misplaced Pages could have been served better by those who are given the authority and responsibility to prevent these monstrosities. Murat (talk) 03:49, 4 July 2011 (UTC)

"It is complete nonsense..." Can you cite here only one nonsense assertion and explain what is nonsense? If you can't, please apologize for the insult. Circuit dreamer (talk, contribs, email) 04:31, 4 July 2011 (UTC)

This has been going on for a long time and it doesn't look like anything will change. The administrators don't seem to want to do anything about this problem. It's not surprising the stickmen drawings are back. No amount of talking will stop this vandalism. The only solution is a permanent ban. That won't happen though. Zen-in (talk) 05:22, 4 July 2011 (UTC)

We just need someone to take the time to work out what would be best in the article (how far back to revert; whether any recent material should be retained). Then some regular "revert to consensus version" will produce results (an editor resisting that would get admin attention). I'm tied up with trivia for a few days and can't do it myself now. Johnuniq (talk) 07:53, 4 July 2011 (UTC)

I disagree with Zen-in; Circuit dreamer's edits are not vandalism. His edits are certainly good faith. The primary problem is his edits reflect his view of the material and not necessarily the view of reliable sources. That is one of the reasons why his edits do not contain references to reliable sources. His edits combined some of his observations with his understanding of theory; he believes those edits are appropriate, but often they are not. Circuit dreamer then compounds the problem by making extensive edits to an article. To me, Circuit dreamer needs to be much more circumspect. I also think that Zen-in should tone things down a little.

I suggest starting with a revert to the last June 16 edit.

Glrx (talk) 17:46, 4 July 2011 (UTC)

The beginning is very good but the final is poor:) I have the feeling that you have started your comment with honourable intentions towards me but then you have forgotten them:) Have you read above how poor just this June 16 edit was? If yes, why have you suggested to revert to it? Please, stop playing the demagogue. Circuit dreamer (talk, contribs, email) 21:32, 4 July 2011 (UTC)

There you go Glrx. I guess you owe someone an apology. Zen-in (talk) 04:50, 5 July 2011 (UTC)

Please read WP:vandalism: "Even if misguided, willfully against consensus, or disruptive, any good-faith effort to improve the encyclopedia is not vandalism." Glrx (talk) 18:05, 11 July 2011 (UTC)

I'm still for the major revert that backs out all C-D's recent edits / WP:OR. Glrx (talk) 18:05, 11 July 2011 (UTC)

• Consensus of 4 to 1 clearly supports reverting this article to some workable version (5 to 1 including me). June 16 was the last meanigful edit without untenable amounts of WP:OR, obtuse verbiage, and other undesireable content. I reccomend that Circuit dreamer's edits concur with consensus on this talk page before being placed in the article. Otherwise, I think it would be appropriate to immediately revert unacceptable edits that are placed in the article with a only a short explanation in the edit history. In other words, I reccomend not wasting anymore time here unless this person's edits are vetted here first. It does not seem to be fair or appropriate to wear down other editors and then take over an article, or a set of articles. For interested parties I have made more general remarks about this situation here. ---- Steve Quinn (talk) 05:28, 8 August 2011 (UTC)

Also, it appears that Circuit dreamer has made over 185 edits to this article beginning on June 23. Most of these or all of these have occoured without some sort of agreement with the other four dissenting editors. ---- Steve Quinn (talk) 05:43, 8 August 2011 (UTC)

Negative resistance was taught in universities fifty years ago. Mathematics and logic was used then. Try v = i . r

71.166.38.174 (talk) 19:58, 20 August 2011 (UTC)

Confusion between V/I and dV/dI

There is a lot of discussion on this page, and I'm sure this topic has been discussed to death already, but I just want to point out that the article in its current state confuses two definitions of negative resistance without flagging this up for the reader, and as a consequence ends up making some false claims. The two possible definitions of negative resistance are

(1) "an increase in the current entering a port results in a decreased voltage across the same port" (taken from the lead), or equivalently, a section of negative slope on the V-I curve of a component or section of a circuit, i.e. negative dV/dI. This is what I normally understand by "negative resistance".

(2) A negative value for V/I.

The lead of the article uses definition (1), but the first section (Properties) is clearly using definition (2), since the figure shows a linear V-I curve passing through the origin, and it makes the claim that "current through a negative resistance implies a source of energy just as current through positive resistance implies that energy is being dissipated." This is true for definition (2) but not for definition (1) - there are passive one-port components such as tunnel diodes that exhibit negative resistance according to definition (1) without adding extra energy to the circuit. This is because, for a nonlinear V-I curve, dV/dI can be negative while V/I is still positive. The confusion probably arises because, for a linear resistor, V/I and dV/dI are always equal.

The next section, History, uses both definitions, referring to (1) as "differential negative resistance" and (2) as "true negative resistance". I think this is a sensible convention, but it needs to be done consistently throughout the article, and the terms need to be properly defined at the beginning.

Nathaniel Virgo (talk) 16:04, 20 December 2011 (UTC)

Neon lamps are a bad example of negative resistance

I did this edit (since reverted) because a gas discharge tube does not have a static I/V characteristic; it is not like a tunnel diode. Some references claim that the subnormal glow is a negative resistance region; others characterize the dark to glow transition as a breakdown (a binary state change); still others characterize subnormal glow as unstable (and map gas concentration and voltage levels). In any event, the distribution of ions is dramatically different between the ordinary dark discharge and the normal glow discharge (which has a cathode fall). It takes time for the organization.

Consider a black box relay circuit with a 1000 ohm resistor in series with a 1000 ohm coil. As the voltage rises across the input, the current increases. When the current gets high enough, the relay actuates and some contacts short out the 1000 ohm resistor. (Increasing current leads to terminal voltage drop.) One can make a relaxation oscillator out of the black box, but I wouldn't call the black box a negative resistor. The I/V characteristic is not static.

I think it is poor practice to claim a gas discharge is a negative resistance. Sources are not clear. Glrx (talk) 23:46, 9 March 2012 (UTC)

Arcs are well-known negative resistance devices (there was at least one amplifier device based on a mercury arc, and the Poulsen arc used for radio transmitters). Neon lamps don't arc (at least, not for very long). In a glow discharge, if I goes up and V stays the same, R has decreased - this is negative resistance behavior, distinct from the initiation of the glow discharge. --Wtshymanski (talk) 15:22, 10 March 2012 (UTC)

Obviously confsing a NDR with a non-existent negative resistance. It does not exist for the same reason a "perpetual motion machine" does not exist! — Preceding unsigned comment added by 173.77.159.236 (talk) 19:26, 22 July 2012 (UTC)

There is NO negative resistance!

There is NO negative resistance. No such element. No such phenomena.The very concept is a violation of numerous fundemental laws of physics. No engineer has ever designed a circuit with a negative resistance. There is no element or circuit that produces V/i < 0! So the real question is why is this article still here? The length of the discussion above should have given someone a clue! It is a shame this platform has been hijacked in this manner. It is a shame that all the elaborate checks and balances have miserably failed to erase this travesty form such a popular reference of truth and knowledge - supposedly! — Preceding unsigned comment added by 173.77.159.236 (talk) 19:23, 22 July 2012 (UTC)

I will reply on the off chance this is a serious comment. If you have a question about the topic of this article, please ask at a forum on some other website, or ask at Misplaced Pages:Reference desk/Science. Electrical engineers talk about things like amplifiers as "devices", despite the fact that more comes out than goes in—no doubt another violation of fundamental laws, or possibly due to the power supply. Johnuniq (talk) 00:55, 23 July 2012 (UTC)

You can buy negative (variable) resistance devices at most drugstores...this one in my pocket now will produce a voltage drop of -1.5 volts when a current of 100 mA flows out of it. That's a negative resistance of -15 ohms. But it will only do that until all the zinc dissolves. --Wtshymanski (talk) 18:53, 23 July 2012 (UTC)

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