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I find existing explanations of memristors are either overly vague, or an unapproachable mass of academic, mathematical analysis. I want to gain an intuitive understanding of what a memristor is, what it does, and what its applications might be in terms accessible to the ordinary engineer.

If an inductor can be emulated with a capacitor and active components, then I bet it's also possible a sufficiently clever circuit could emulate a memristor, at least within a limited region of operation. Though this circuit may not have the same properties that make memristors potentially useful, it could still be a useful demonstration and platform for experimentation.

Is there something I can build on a breadboard that looks, within some reasonable operating operating parameters, like a memristor? If not, what about something that can be simulated with ideal components? Bonus points for summarizing the theory of operation, and succinctly and intuitively describing what a memristor is without resorting to abstract mathematics or models far removed from even idealized real components.

Phil Frost
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  • This is a similar, less precise question http://electronics.stackexchange.com/questions/74775/is-anyone-producing-discrete-memristors (I know you saw it already, Phil, but for everyone else I am linking it.) – travisbartley Jul 17 '13 at 03:32
  • @trav1s, bad link (here at least). Did you mean this? [Memristor Emulator for Memristor Circuit Application](http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=6183495&url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel5%2F8919%2F4358591%2F06183495.pdf%3Farnumber%3D6183495) – Iancovici Jul 17 '13 at 12:05
  • @echad, sorry about that. That is the one I wanted to share, yes. – travisbartley Jul 18 '13 at 01:31

2 Answers2

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The answer is: Mutator. Or maybe: M-R mutator.

The gyrator, used to emulate some properties of an inductor using a capacitor, is a subset of a mutator. I am not aware of a specific name for the type of mutator that gives you a memristic behavior (other than M-R mutator), but it seems like you can actually build it with real, existing components:

M-R Mutator

Source: Memristor - The Missing Circuit Element, Leon O. Chua, IEEE Transactions on Circuit Theory, Vol. CT-18, No. 5, September 1971.

The paper also shows how you can build a curve tracer for a memristor, i.e. a device that shows you a diagram for charge vs. flux-linkage. While there's a lot of theory in the paper, I like it because there are actual circuits I am sure one can breadboard and hack around with.

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zebonaut
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    I was hoping that the circuit would be simpler, but I guess my hopes don't change reality. – Phil Frost Jul 18 '13 at 18:21
  • @PhilFrost: Well, usually, Chua seems to be one of those who go for the most elegant solution, where elegant = simple. (Just replace the vintage OpAmps ;-) The whole idea of predicting the Memristor back in 1971 would not have happened without this philosophy, I guess. Same with his research on chaos ("Chua's Circuit"): His paper "The Genesis of Chua's Circuit" is a piece of beauty (https://www-inst.cs.berkeley.edu/~ee129/sp10/handouts/GenesisChuasCircuit.pdf). I really like how he rules out everything too complicated and arrives at the easiest circuit to do the job. – zebonaut Jul 18 '13 at 18:55
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People have been working on this. A lot (most) of the stuff you see (as you mention) isn't something that anyone without a huge lab would even think of trying.

Here is a paper by Muthuswamy, who has worked with Chua, I think.

Here is a copy of the circuit schematic:

enter image description here

The circuit looks doable. It does use 2 multipliers (AD633JN) that are probably about $5 each, but it is not too complicated.

The paper has a lot of information about the circuit and its design. If you like Mathematica, it has a model based in that as well.

It looks like to be really up on the Mem_x_technology you will have to read up on Memcapacitors and Meminductors too. (Not kidding, they are out there).

gsills
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