Talk:Negative resistance/Archive 4

message: 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)
thread_title:  Rewrite 

message: 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)
thread_title:  Moving the content about negative differential resistance to its page 

message: 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)
thread_title:  Moving the content about Deborah Chung's "apparent negative resistance" to a new page 

message: 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:
* Negative impedance element is an electronic circuit, not an element (a component). There are not true negative impedance elements; there are only negative differential resistance elements.
* Negative impedance element is a two terminal (1-port) electronic circuit
* Negative impedance elements are sources that inject energy into circuits while the according passive elements (resistors, capacitors and inductors) absorb energy from circuits
* Negative impedance element is not an ordinary, steady source; it is a dynamic source:
** it may be a dynamic voltage source that produces voltage depending on the current passed through it in the same way as the voltage across the resistors, capacitors or inductors depends on the current passed through them;
** it may be also a dynamic current source that produces a current depending in the same way on the voltage applied across it as the current passed through the resistors, capacitors or inductors depends on the voltage applied across them.
* Negative linear resistance is a special but the most popular case of the negative impedance phenomenon
* There are also non-linear negative resistors (e.g., "negative diodes")
* Also, we have to mention the most typical applications:
** Elements with negative impedance are used mainly to compensate the losses in elements having the same "positive" impedance
Please, comment my insertion. Circuit-fantasist (talk) 09:15, 28 January 2009 (UTC)
thread_title:  Reconstructing the top introductory text 

message: 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)
thread_title:  Renaming the title from "Negative resistance" to "Negative impedance" 

message: 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:
* True negative impedance elements do not exist in nature; so, we have to create them
* The basic idea: to "copy" the voltage drop across the "positive" impedance element (by a voltage follower) and to add an equivalent voltage to the input voltage
* Putting in practice the idea: making an op-amp produce a "mirror" voltage by using a negative feedback. Revealing the role of the op-amp in all kinds op-amp inverting circuits witn negative feedback. Circuit-fantasist (talk) 11:00, 29 January 2009 (UTC)
thread_title:  How to create simple negative impedance elements 

message: 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)
thread_title:  How to create true one-port negative impedance elements 

message: 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)
thread_title:  I nominate this page for deletion  

message: 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)
thread_title:  What negative impedance is 

message: 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)
replies: text: I disagree. This is not an unintelligible circuit. It is not a complex subject and therefore does need excessive complexity to explain it. Debating semantics is not the answer either. Madhu (talk) 03:55, 13 February 2009 (UTC)
thread_title:  As a conclusion 

message: :Could you take a look at the negative resistance article and its talk page? The article is on the verge of being completely removed (and hopefully rewritten) and we'd appreciate more opinions. Thanks. -Roger (talk) 18:50, 17 February 2009 (UTC)
replies: text: I have been trying to improve the negative resistance article.  This electrical phenomena that this article is about is generally termed "negative resistance" by Electrical Engineers.  I have found no case where this effect is called negative impedance.  In general negative resistance is a quasi-DC phenomena and the impedance of devices ( ie: scattering parameters ) is a separate matter.  Originally this article was titled Negative Resistance.  In May 2008 I remarked on it's talk page (now archived somewhere) that the article was a real mess, was technically incorrect and mostly OR.  Others agreed and so I asked for a vote to allow me to improve the article.  A couple of editors agreed.  My attempts to improve this article just get reverted immediately by Circuit-fantasist, who after awhile has spun off parallel articles called Negative_impedance and Negative_differential_resistance.  So I restored Negative Resistance and have started working on it.  From your discussions it appears you value the contribution of Circuit-fantasist and don't want to see it changed.  I am not one to fight an uphill battle so I will leave you to your world of Cargo_cult_science articles and go back to doing what real EEs do.Zen-in (talk) 21:42, 17 February 2009 (UTC)
replies: text: This isn't really the place to be discussing this stuff. Let's please communicate via my talk page. -Roger (talk) 22:12, 17 February 2009 (UTC)
replies: text: (ec) (to Zen-in) Please do not be insulting.  If you disagree with the name change you should discuss this on the Negative impedance article talk page.  If you disagree with the split of the article, you should discuss a re-merger on the talk pages.  This is the right way to proceed.  Re-creating the article as you like it at Negative resistance is the wrong way to proceed, this is a fork, there should be only one article. SpinningSpark 22:16, 17 February 2009 (UTC)
replies: text: Sorry if you find my directness to be insulting. I have tried to improve the article and have seen all my changes get deleted.  Do you believe that C-F owns the rights to this article? I don't see any effort on your part to convince him to allow others to edit it.  Instead you have criticized me on a number of small matters.   C-F's writings do not belong in the electronics realm.   They are just a product of his over-active (over-helping?) imagination.  It all needs to be expunged from Wikipedia and re-written by competent authors.   If you are not willing to support this you have no credibility with me. I don't need Wikipedia for anything if it becomes filled with Bizarro Cargo_cult_science articles as written by C-F.Zen-in (talk) 23:09, 17 February 2009 (UTC)
replies: text: I agree that there is a lot wrong with C-F's writings but this needs tackling head-on, not by producing a fork article.  The first thing that needs to happen here is that the fork article is removed and all the discussion and effort is centred around the one remaining article.  I am willing to help but I do not support forking the article and it is against Wikipedia guidelines.  Are you willing to return the negative resistance article to a redirect and move all edits and discussion to negative impedance?, (which can include discussing changing its name).  And please stop accusing me of cargo cult science, I am a trained electrical engineer and fully understand the difference. SpinningSpark 23:23, 17 February 2009 (UTC)
replies: text: Go ahead and do what you want.  I have washed my hands of the matter for the time being.  If I see any improvement in the situation my interest in Wikipedia may be restored.Zen-in (talk) 23:47, 17 February 2009 (UTC)
replies: text: It's not a question of what I want, I had nothing to do with this article until a few hours ago when Roger asked me to look at it.  Your help is needed too to get this improved.  This is only going to work if everyone collaborates.  Washing your hands and leaving it to me is not going anywhere.  I am not about to fight one edit war by starting another and undoing your edits to negative resisitance.  I need you to indicate that you accept there should be only one article and it would be best if you put it back to one article yourself.  That way it is clear to everyone there is no edit warring going on.  We can then all move on and start improving the negative impedance article.  The alternative is to start an AfD which would be just so horribly messy I don't want to think about it and it would be wasting effort better spent on improving the article. SpinningSpark 00:03, 18 February 2009 (UTC)
replies: text: You are asking me to do exactly what I have been trying to do for the past few weeks.  All my edits have been reverted by Circuit-fantasist.  That is not going to change.  Until something is done to change that situation I have more productive things to do.Zen-in (talk) 00:30, 18 February 2009 (UTC)
replies: text: Reverting someones edits without justification is not permitted. If C-f has been doing so, then you simply need to bring it to an admins attention. -Roger (talk) 00:39, 18 February 2009 (UTC)
replies: text: C-F is unlikely to revert the edit I am asking for here.  It is what he wants. SpinningSpark 00:47, 18 February 2009 (UTC)
replies: text: If it is what C-F wants then why are you asking me to do anything?  As I have stated before until C-F is out of the picture entirely I am not wasting any more of my time with this amusing edit war.Zen-in (talk) 00:53, 18 February 2009 (UTC)
replies: text: I am asking because you created the fork and it is far less confrontational if you remove it.  I am asking because a good place to start is something that all sides agree on.  You do agree that there should only be one article for one subject don't you? SpinningSpark 00:59, 18 February 2009 (UTC)
replies: text: I never agreed to having Negative Resistance redirected to Negative Impedance.  You removed my edits without my consent.  The subject matter is negative resistance and the original article was titled negative resistance.   Sorry, I'm not going to be your proxy sock puppet for C-F.  Your credibility with me just took another dive.Zen-in (talk) 01:14, 18 February 2009 (UTC)
replies: text: Oh sorry, Go ahead and do what you want. I have washed my hands of the matter for the time being. seemed quite clear to me that you would not oppose this even if you were not willing to it yourself. SpinningSpark 01:21, 18 February 2009 (UTC)
replies: text: You can use whatever justification you want.  You were going to do it with or without my participation.  Your request "I am asking because you created the fork and it is ..." was completely dishonest.  Before I replied you went ahead and deleted my edit.  I will not work with someone like you.  It will amuse me to see more junk science articles added to Wikipedia.Zen-in (talk) 01:36, 18 February 2009 (UTC)
replies: text: Ok, I don't want you to think I am steam-rollering you so I will put it back.  I need to go to bed now, so I will not respond again tonight (this morning), but if you insist on having both articles around it is going to have to go to AfD.  As I say, it is going to be much more straightforward if there is only one article for everyone to work on. SpinningSpark 02:16, 18 February 2009 (UTC)
replies: text: It was not I who created the forks.  The original article was Negative Resistance.  C-F created Negative Impedance and Negative Differential resistance.  Your statement in Talk:Negative_resistance about xyz impedance, Laplace, complex frequency notation, etc is just nonsense.  The correct title for this subject  is negative resistance, as it was originally.  However I understand why you are so eager to build on what C-F has started.  My earlier assertion has proven to be correct.Zen-in (talk) 05:22, 18 February 2009 (UTC)
thread_title: Edit discussion

message: 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)
replies: text: Oh sorry, if anyone can't find the other discussion it's here. SpinningSpark 18:17, 19 February 2009 (UTC)
thread_title:  Propose move to Negative resistance 

message: 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)
replies: text: Hey, glad to see you're back. Feel free to work on what you like. I'd like to build up some momentum to tackle the other articles that are in exactly the same state as this one (after we finish here) and think that a couple more bodies will lighten the load for the rest of us. If you don't have your heart set on drawing the pics, User:BillC indicated an interest in contributing in this area, and you might like to explicitly invite him to knock up a graph or circuit-diagram (if a c-d is even needed). I'd start on the text but my first impulse is to completely remove what's there now (and then jump up and down on it in my boots before setting fire to it and hurling it over a cliff) but perhaps there is something worth saving? Up to you.  Secret Squïrrel 01:38, 20 February 2009 (UTC)
replies: text: I think everything from "Negative impedance implementations" to "Generalizing" can go, as well as any OR references.  Most of this talk page could be archived as well, some of it is getting old.  The remainder all will be useful once it is tied together.  Rogerbrent and I both started the lede and I'll merge those later tonight. Thanks for jumping in when you did.  I'm happy with how this has progressed and I think almost everyone is in agreement with the outcome.Zen-in (talk) 02:34, 20 February 2009 (UTC)
thread_title: Edits

message: 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)
replies: text: Image numbering is inconsistent at the moment, eg fist image is un-numbered, second figure is labelled as fig 5, text refers to non-existant fig 1a (legacy from a previous article).  Obviously this can't be resolved until the article's structure becomes more stable, so I just mention this as a reminder of a copy-edit task we'll have to keep on the to-do-list. -- Timberframe (talk) 11:30, 20 February 2009 (UTC)

text: Thanks for redrawing the diagrams   SpinningSpark. However I think four variations on the same circuit is too much. I suggest we replace them with one that covers all possible cases (i.e. in terms of Z_1, Z_2 and Z_3). -Roger (talk) 17:44, 21 February 2009 (UTC)
thread_title:  New images 

message: 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)
thread_title:  "Apparent Negative Resistance"

message: 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)
replies: text: Zen-in, I am glad to see that we can already discuss concrete circuit ideas and phenomena; this is quite more useful than talk big. Really, how op-amps work is a key point to understanding op-amp circuits. When I was a student in middle 1970s, reading classical explanations (they still exist) I couldn't understand what and how an op-amp really does in op-amp circuits with negative feedback. Later, in middle 1980s, when I began explaining basic op-amp circuits with negative feedback to my students, I realized gradually a paradoxical fact: although an op-amp is really a proportional and, as they consider, an almost "non-inertial" device, in order to understand how op-amp circuits work, we have to think of it as an integrating, inertial device what it actually is (see also op-amp myths, Integrator inside section). Figuratively speaking, we have to think of the op-amp as a "being" that "observes" continuously its input voltage and changes its output voltage until it manages to zero the input voltage. If we think of the op-amp in terms of UOUT = A.VIN (i.e., VIN and UOUT change simultaneously), we fall into a vicious circle traveling the feedback loop and we can never understand circuit operation. We have to assume that the output voltage stays late regarding the input voltage. More philosophically speaking, we have to see the causality in the op-amp operation; to think of the input voltage as a cause and of the output voltage as a result. Quite later I found this concept in The art of electronics, "The golden rules" section (p. 177): What the op-amp does is "look" at its input terminals and swing its output terminal around so that the external feedback network brings the input differential to zero (if possible). As you can see, Horowitz & Hill have also animated the inanimate op-amp with the sole purpose of showing what it actually does in negative feedback circuits. I will use this technique later to consider your circuit  emulating a negative resistor. Circuit-fantasist (talk) 18:04, 20 February 2009 (UTC)
replies: text: Circuit-fantasistYou have already used this circuit and done your kind of analysis on it.  It's near the bottom of the section on op-amp circuits.  The basic circuit is there but you have added some stuff and created a separate ground for one node.  I like to use Kirchoff's Current Law to analyze op-amps.  It always gives me a result that agrees with what the circuit is actually doing.  And I don't have to add imaginary components.   The goal is to figure out the transfer function of the circuit, so that you know what the circuit will do when you drive it with an input.   I don't see where you have ever been able to do that. Zen-in (talk) 20:55, 20 February 2009 (UTC)

text: The section (now named "Op amp negative resistor") is factual as it stands, but lacks notes on practical applications.  In contrast to the applications suggested in the "Properties" sections such as compensating for telephony repeaters where accurate reproduction of the input signal is a pre-requisite, this circuit converts any input signal which is not extremely close to zero volts to a signal which chops between the supply rails.  Unless we can add some real-world applications for this output function in combination with a need for negative resistance this seems like a trivial and non-notable illustration of negative resistance.  (This is close to my objections to C-F's previous version of the article: negative resistance as an incidental consequence of some other function is non-notable, as is a circuit which demonstates negative resistance but has no practical application.) -- Timberframe (talk) 11:17, 20 February 2009 (UTC)
replies: text:  Thanks for adding the more practical implementation. -- Timberframe (talk) 13:50, 20 February 2009 (UTC)

text: The final paragraph ("Electrical elements with negative impedance are extremely useful... they convert the positive impedance into negative one") seems out of place (it's general introductory stuff, but most of its points have already been made) and unduly laden with peacock phrases.  It also introduces negative impedance which, I think we agreed, clouds the issue.  I hesitate to edit it without discussion in case someone put it there for a good reason which I haven't appreciated.  -- Timberframe (talk) 11:23, 20 February 2009 (UTC)
thread_title:  Basic active negative resistor 

message: 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)
replies: text: You're probably right. I didn't pay any attention to it myself, so it could all be nonsense. -Roger (talk) 15:35, 20 February 2009 (UTC)
replies: text: I agree. In fact I was about to re-iterate the comment near the top of this page about "sources, sources, sources." There's a danger that, like C-F, we end up writing a textbook from our first-hand knowledge rather than compiling an encyclopedic survey of documented knowledge. What we're doing at the moment is not encyclopedic and can't be regarded as more than mapping out the structure and general subject matter of a yet-to-be encyclopedic article. That's not a bad way to do it, but we must keep one eye on tracking down reputable sources to back up our knowledge (sounds like you have one for the history) and the other on ensuring the scope is not limited to what we know. -- Timberframe (talk) 15:49, 20 February 2009 (UTC)
replies: text: Looking back on the original edit by an IP in 2005  I am even more convinced it should go.  It seems to be one of those cases where a dubious edit looks better after the copyeditors have been at it.  Certainly the phrase referring to "the circuits above" was added later by an editor making too many assumptions. SpinningSpark 19:43, 20 February 2009 (UTC)

text: Slightly unfair comment on the sources as I have added four so far, but I agree, we still need more, particularly for the specific circuits. SpinningSpark 19:58, 20 February 2009 (UTC)
thread_title:  History section 

message: 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)
replies: text: Derivations, like paragraphs, aid in understanding. More importantly, they improve transparency (although they are no replacement for citations). Also, don't people turn to an encyclopedia to see how (for example) "lift" keeps a plane in the air? How is that different to asking how an important result is derived? One of the reasons why derivations/proofs are discussed in non-mathematical curriculum is because the derivations themselves add to the result. —TedPavlic (talk) 20:12, 20 February 2009 (UTC)

text: Roger, the answer to that question is at Wikipedia:What Wikipedia is not#Wikipedia is not a manual, guidebook, or textbook, particularly point 4. SpinningSpark 20:46, 20 February 2009 (UTC)
replies: text: You and Ted seem to be at a disagreement over this. I'll wait and see what others have to say. -Roger (talk) 21:06, 20 February 2009 (UTC)

text: I agree with TedPavlic that derivations aid understanding of the stated result.  Furthermore, if I'm understanding correctly the distinction made in Spinningspark's citation it would appear to permit derivations: "Other kinds of examples, specifically those intended to inform rather than to instruct, may be appropriate for inclusion in a Wikipedia article". Derivations inform the reader why the result is as stated rather than 'instructing readers on the techniques of circuit analysis so that they can learn how to derive the result for themselves. -- Timberframe (talk) 21:45, 20 February 2009 (UTC)
replies: text: True, but in many cases the derivations amount to just applying KVL/KCL and some basic algebra. The negative impedance converter article is a good example of how unnecessary this over elaboration can be. -Roger (talk) 17:49, 21 February 2009 (UTC)
thread_title:  Are derivations necessary (or even encouraged)? 

message: === What does "to understand circuits" mean? ===
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)
thread_title:  How do op-amp negative impedance circuits (INIC) work? 

message: 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)
thread_title:  What does "to understand circuits" mean? 

message: 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)
replies: text: I have a better idea: Remove your graffiti Zen-in (talk) 20:45, 22 February 2009 (UTC)
thread_title:  Suggestion for archiving