Menristor Seminar

Professor Leon Chua received his MS and PHD degrees from the Massachusetts Institutes of Technology and the University of Illinois at Champaign-Urbana. He is currently a Professor of Electrical Engineering and Computer Sciences at the University of California, Berkeley.

He was the first recipient of the IEEE Gustav Robert Kirchhoff Award in 2005 and was awarded the IEEE Neural Pioneer Award in 2000. He received many international prizes, including the IEEE Browder J. Thompson Memorial Prize and the IEEE W.R.G. Baker Prize. He is the recipient of seven USA patents and 12 Honorary doctorates from universities in Europe and Japan.

He was elected a foreign member of the European Academy of Sciences and the Hungarian Academy of Sciences. In 2010, he was awarded a John Guggenheim Fellow and the Leverhulme Trust Visiting Professorship.

In 2011, he was awarded a Royal Academy of Engineering Distinguished Visiting Fellowship within Imperial College London.

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). Then, in a brilliant but underappreciated 1971 paper, Leon Chua, a professor of electrical engineering at the University of California, Berkeley, predicted the existence of a fourth fundamental device, which he called a memristor. 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.

            Memristor is a contraction of “memory resistor,” because that is exactly its function to remember its history. A memristor is a two-terminal device whose resistance depends on the magnitude and polarity of the voltage applied to it and the length of time that voltage has been applied. When you turn off the voltage, the memristor remembers its most recent resistance until the next time you turn it on, whether that happens a day later or a year later.

            Chua discovered a missing link in the pair wise mathematical equations that relate the four circuit quantities-charge, current, voltage, and magnetic flux-to one another. These can be related in six ways. Two are connected through the basic physical laws of electricity and magnetism, and three are related by the known circuit elements: resistors connect voltage and current, inductors connect flux and current, and capacitors connect voltage and charge. But one equation is missing from this group: the relationship between charge moving through a circuit and the magnetic flux surrounded by that circuit.

            These Memristor has the properties of both a memory element and a resistor (hence wisely named as Memristor). Memristor is being called as the fourth fundamental component, hence increasing the importance of its innovation.

            Leon Chua said: "Since our brains are made of memristors, the flood gate is now open for commercialization of computers that would compute like human brains, which is totally different from the von Neumann architecture underpinning all digital computers."

Memristor technology also promises dense, compact memory packages, on par with the density capability of a biological brain. Memristors can be made extremely small, at nanometer scales. Already HP labs have designed circuits that mimic aspects of the brain. Transistors are used as neurons, nanowires in a crossbar network act as axons and the memristors at the cross points act as synapses. In the future, even the transistors might be replaced by memristors.