The memristor—the functional equivalent of a synapse—could revolutionize circuit design | Hacker News Reader

The memristor—the functional equivalent of a synapse—could revolutionize circuit design

spectrum.ieee.org

64 pointsprakash15 comments

Fascinating article. It really gives a great feel for how real breakthroughs are made. And it shows what kind of environment is necessary:

But beyond the comment that “molecular-scale electronics” would be interesting and that we should try to have something useful in about 10 years, I was given carte blanche to pursue any topic we wanted. We decided to take on Moore’s Law.

There aren't many places today where that kind of research is going on. Maybe successes like this will remind some of those in a position to make a difference what kind of commitment is required to discover truly revolutionary ideas.

You see the same sort of environment revealed in the "good old days at Bell Labs" that was posted a few days ago.

This is a fantastic example of exposition. I don't know anything about nanotechnology, but the author made it easy to follow the explanation.

Early in the article:

"[Chua] proved that memristor behavior could not be duplicated by any circuit built using only the other three elements, which is why the memristor is truly fundamental."

Later in the article:

"Emulating the behavior of a single memristor, Chua showed, requires a circuit with at least 15 transistors and other passive elements."

Reconciliation?

The three elements are the capacitor, inductor and resistor.

I think when they say "fundamental elements" they mean the fundamental passive elements of analog circuit theory (mentioned above), as opposed to active elements like op-amps or transistors.

Exactly, it says that at the top of the paragraph.

"For nearly 150 years, the known fundamental passive circuit elements were limited to the capacitor (discovered in 1745), the resistor (1827), and the inductor (1831)... He proved that memristor behavior could not be duplicated by any circuit built using only the other three elements, which is why the memristor is truly fundamental. "

Thanks, think I got it -- the passive elements can't duplicate a memristor, but transistors plus some passive elements can.

ok so the reverse is interesting - the memristor can presumably do what those "active + passive" components could have, but cheaper/smaller/faster better etc? Did I get it right?

Yes. At the moment, only smaller (the devices operate at ~1 Hz but may improve). The end hope is for very high density RAM or solid state memory (depending on how fast it ends up compared to SRAM and DRAM and Flash).

The "three elements" are, I assume, resistors, capacitors and inductors.

http://news.ycombinator.com/item?id=388562

http://news.ycombinator.com/item?id=385322

http://news.ycombinator.com/item?id=362005

Perhaps, but the claims regarding brain emulation and "thinking" are way off. To begin with, we don't even know the biological basis of thinking--neurons firing is something even a slug can do, and has as much to do with thinking as walls and doors have to do with a research institute.

It's like saying: since we understand gravity now, designing spaceships with warp drive is just round the corner.

Yes, calling something "the functional equivalent of the synapse" implies you know the function of a synapse...

The memristor has some functional properties in common with some synapses.

Neither synapses nor memristors have been fully characterized (though probably the memristor is better understood at this point).

The function of synapses in memory formation and information processing is poorly understood, but maybe having a nanoscale electronics component (memristor) that has some synapse-like attributes will increase the size of simulations to the degree that they will make interesting, testable predictions about how neural circuits work.

Yes, the brain analogy is grandiose fluff, which is a pity because the content is mind-blowing enough without it. If the discovery is as fundamental as the article implies, there's no telling what will be made of it.

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