HP's fourth element

All electronic engineers have heard of the resistor, the capacitor and the inductor. Now, researchers at HP Labs claim to have proved the existence of a fourth basic electronic device.

The so-called memristor - short for memory resistor - could make it feasible for engineers to build systems with memories that retain information even after the power is off.

A mathematical model and a physical example that prove the memristor's existence appear in a paper published in the April 30 issue of the journal Nature.

'To find something new and yet so fundamental in the very mature field of electrical engineering is a big surprise,' said R. Stanley Williams, an HP Senior Fellow and director of the Information and Quantum Systems Lab (IQSL).

The memristor first appeared in a 1971 paper published by Prof Leon Chua, a distinguished faculty member in the Electrical Engineering and Computer Sciences Department of the University of California Berkeley.