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In my opinion whatever thing you want to call fundamental circuit element should have a relationship to the physical reality strong enough that theoretical mode
by dfox 8y ago
In my opinion whatever thing you want to call fundamental circuit element should have a relationship to the physical reality strong enough that theoretical model consisting of some idealized conductive solids of trivial-ish geometry works for most of the practical problems. L, C and R satisfies this test with various levels of "-ish" (with R being the hard one) and handwaving, while nobody even knows how to model an memristor in that view.
- ndesaulniers 8y ago> while nobody even knows how to model an memristor in that view. Isn't hysteresis the model? Pretty sure that model was in the original paper introducing the concept of memristors by Chua, IIRC.
- dfox 8y agoMy point is that you can take length of insulated wire, do something relatively trivial to it and end up with single port device that is decidedly mostly L, C or R. You can not construct practical memristor that way.
- function_seven 8y agoJust to make sure I'm following you: R would be a long piece of wire, L would be a coiled piece of wire, and C would be two wires in parallel, for some distance?
- dfox 8y agoIn my original idea, C would be twisted pair, but from the theoretical standpoint, that does not matter, so yes. The idea is that the whole circuit theory is motivated (as is the rest of physics) by ability to describe phenomena that can be practically observed, and should not invent things that only should exists to preserve mathematical purity when such concepts have no real world equivalent nor are useful as simplified model for something.
- milesvp 8y agoI’m not sure I agree with you on this. I once read that pure maths tends to preceed applied maths by about 50 years. I don’t know how true it is, but if the practitioners aren’t constantly chasing some ideal version of reality, I’m not sure we would get the same major advances in industry. I think you may also have a dated idea as to ‘real world equivalent’. We’re in a very interesting time for meta materials. Things like negative index of refraction was pure science fiction 20 years ago, but today we can make multilayered substances that behave as though they have a negative index. Which is to say, that if we can make it, it now has a real world equivalent. Even your example of a wire ignores the enormous amount of materials processing necessary to produce wire. Wire was unimaginable maybe as recently as 10k years ago.
- function_seven 8y agoI'm on the fence between you two. On one hand, it's true that missing pieces in a mathematical symmetry often motivate us to go find the real-world thing we haven't observed. On the other hand, your example of a multi-layered substance that exhibits negative refraction does seem like "cheating". We can make transistors by layering different doped silicone variants together, but it's not considered a fundamental electrical component. If memristors require the same amount of engineering, are they "natural"? What would be fascinating is, what if the missing puzzle piece implies an exotic shaping of "just" wire that would act as a memristor? Some crazy contortion like the magnetic field designs I've seen for containing fusion reactions.
- TheOtherHobbes 8y agoIndeed you can't. You also can't construct a diode or a transistor. There are two parallel arguments here. One is yours. The other is whether or not it's possible to construct a resistor with memory at all. It clearly isn't if you all you have is copper wire. But copper wire is only fundamental in the 19th century pre-semiconductor sense. None of the practical memristor models assume that. They all rely on junction effects, spin effects, and other exotica.
- fhars 8y agoYou are arguing that the memristor is an interesting active device like a transistor (which it may be, and which isn't addressed by the article). What the article argues against is the claim that is a the long missing last fundamental passive device.
- mmusson 8y agoThe paper has an interesting perspective but much of it felt wierd. I looked in my old Basic Circuits textbook and the phrase fundamental circuit element isn’t used at all. From an EE perspective, the usual basic groupings are passive and active, and linear and non-linear, because that directly relates to how to mathematically solve circuits including the components. They ignore diodes in the paper because they do not cleanly fit any of their categories. Also the frequency domain behavior/description of each component is perhaps more important.