Friday, May 16, 2008

Electrical Engineers, Rejoice!

The long-sought-after fourth component has been found!

Seriously. No, I'm not joking.

It's called a memrister.

And it's going to render every electronics/circuits book in the world obsolete. Well, maybe not obsolete, but definitely in need of revision. I'm not going to bother discussing its merits/uses in this post. The articles do a darn good job of that.

But please feel free to start a discussion in the comments.


Junyor said...

I don't know about it being the forth element. One concern is that the fundamental elements should be linear devices, which represent different cases of general AC impedance, or at least that an ideal linear device should be possible. A memristor should then be classified as a non-linear two terminal device, instead of as a "basic element", because a perfectly linear memristor is equivalent to an ideal resistor.

Hold on...I am not an eletrical engineer, I just stayed at a Holiday Inn Express last night.

Barrett B. said...

If you'll notice, the equation for memristance (M) is given as the change in flux with respect to the change in charge.

There are two possible cases in which this device can be included. The first is a simple DC circuit where there is only a change in charge when the circuit has voltage applied to it or not. The activated/non-activated states are the only situations that will have an effect on the memristor, and thus it will behave like a simple resistor after activation. Except that its resistance will be determined by the current through the circuit at start-up rather than being inherent to the component.

The second is in an AC circuit. In these circuits, the change in flux is determined by the inductance of the circuit with respect to the change in current. The change in current is limited to linearity by the very inductive nature of the circuit. The change in charge is determined by the capacitance of the circuit with respect to the change in the voltage. The change in voltage is limited to linearity by the very capacitive nature of the circuit.

Ergo, a circuit that utilizes all four components is linear.

Actually, now that I think about it, I don't believe there's a single case using any possible combination of components that will not be linear. I could be wrong and would love to see the math on that proof.

Junyor said...

I don't know if Mr. Faraday would agree. Your argument is that it doesn't matter if resistance, capacitance or iductance is a constant value. A fundamental circuit element is characterized by a specific relation between voltage, current and/or time. Memristance relates in the same way as resistance and its identity can only be expressed when it is a certain type of function.

Barrett B. said...

Ummm...Are you sure you stayed at a Holiday Inn Express last night? 'Cause that's not at all what I was getting at.