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Comment by frik | Hacker News Reader

Conceptual symmetry between the resistor, capacitor, inductor, and the memristor:

http://en.wikipedia.org/wiki/Memristor#mediaviewer/File:Two-...

The scales fell from my eyes. Now the electronics math makes sense - Memristor was the missing puzzle piece.

I can't help but notice that the region occupied by the memristor is what would be best described as a 'flux-capacitor'. You really can't make this stuff up.

That reminds me of the missing mechanical equivalent of the capacitor, the inerter, which McLaren secretly began using on their formula one cars in 2005. But does this mean there's potentially another missing suspension component?

http://personal.strath.ac.uk/yixiang.xu/talk_HUST_2008_Chen....

edit: Assuming a Force-Current, Velocity-Voltage equivalence, I get the mechanical memristor behavior to be: dx=M.F.dt, with M being a property of the memristor(memdamper?). Or in other words, v=M.F; velocity is proportional to the force. (The dots are multiplication. Asterisks italicize the text)

v = M.F => that's regular inertia isn't it? In the case of the inerter presumably constrained by the stroke of the device. It's like a 'two stroke flywheel' in a nice package.

As explained at http://www-control.eng.cam.ac.uk/~mcs/lecture_j.pdf, mass with respect to the inertial frame is equivalent to a grounded capacitor. However, the single "pole" limited the sorts of mechanical systems that could be designed. The inerter allows a system to be optimized with respect to the difference between accelerations, not simply an absolute acceleration.

I think that two accelerations could also be related with levers, but the quantities involved might make that not so feasible as a suspension component.

It's great material for a T-shirt.

what an awful diagram. it implies there's some kind of symmetry that relates all four, but when you look at the details there are asymmetries. if you think it was helpful look at it again and explain why di appears in two quarants but dq and dv appear once each.

are you sure you're looking on both sides of the equations?

You can rearrange the inductor equation to get di = (1/L) dϕ. Then the quadrants are perfectly symmetrical except for the ugly 1/L. But that's just an arbitrary unit created by humans, you could fix that by defining the unit of inductance as the inverse of what we use now.

ah, thank-you. that makes more sense.

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