Interesting New Passive Component?

It is a new type of diode. Since a diode is any active part with two legs and this part can't really be called passive I suggest that the term diode be applied to it.

The article is full of the usual wild claims that nontechnical reporters tend to put in articles about technical subjects, but reading around those claims, it is an interesting and perhaps useful device.

Well, it seems the guy writing that article doesn't have much of a EE background...

"Hysteresis has been explained away by current circuit theory as an anomaly..." Really? I kinda doubt the folks making ferroresonant transformers or mag amps or core memory considered hysteresis an "anomaly..."

Some of the discussion about passivity looks completely wrong too. "changes in voltage, or flux" -- huh? Maybe they mean electric field flux or something?

Doesn't sound like a two-terminal device, in the intended application. The change of state is delivered by a second current path.

RL

That is not how I read it. Where is the second current path in a crossbar switch? There is only the upper and lower crossbar wires. With the lower layer nonconductive the switch looks like a capacitor with a high value resistor in parallel, when the lower layer is made consuctive with suitable di/dt into the capacitor (programming pulse) then it becomes a capacitor in parallel with a low resistance. State of the resistor then read with a pulse with too low a di/dt to change the state. Sounds like a two terminal device to me. The low power

100 Gbit memory device they claim to have already produced sounds like something I hope goes into production, it will be interesting to see if it does. Interesting article any way you look at it, thanks for the post Mark.

Regards, Glen

Two wires = 4 terminals. Look at the picture.

The changing resistance does not occur within the control wire, but within/between the layers of titanium dioxide. I'm puzzled by the apparent lack of reversibility in the process of creating and erasing 'oxygen vacancies', unless simple reversal of current direction in the 'control wire' suffices.

A two terminal network requiring current flow to block would be a one-shot fuse, to open. Getting a low Z branch to store charge is a contradiction of terms. An infinitely low impedance could store energy, in charge-flow-generated flux, but inductors are not used for this purpose in any lengthy time frame for just that impractical reason.

A two terminal device requiring current flow or charge storage to avalanche-conduct would also be a one-shot, to short.

A third terminal (minimum) is still required for a control, to remove or introduce the charge.

No doubt the aim or the basic acheivment may involve a two wire structure, but the present application does not. Two wire elements with memory (like tunnel diodes and other dynamic elements that serve the purpose) are tricky to actually use, without complex refresh.

"When Chua wrote his seminal paper, he used mathematics to deduce the existence of a fourth circuit element type after resistors, capacitors and inductors"

A resistor isn't a circuit element - it's just a degree of conductor, as 'opposed' to being a degree of insulator. There was never a triangle that needed to be squared. These 'elements' already operate at 90 and 180 degrees to each other. Chua was merely indicating that possible new elements with memory 'memory' of being either one or the other, should be considered.

"a misconception that has pervaded electronic circuit theory(...)is that the fundamental relationship in passive circuitry is between voltage and charge. What the researchers contend is that the fundamental relationship is actually between changes-in-voltage, or flux, and charge."

Thats voltage with stored charge as potential energy, in joules ( C x V^2 / 2 ), and current with stored flux as potential energy, also in joules ( L x i^2 /2 ).

It would be nice to see sensitive linear flux sensors coming out of this. A switch is nice, and efficient switches are essential in power conversion and logic, but a linear effect would show real mastery of the phenomena.

RL