While electronic circuits and nanomachines grow ever smaller, batteries to power them remain huge by comparison, as well as short-lived. But now Cornell University researchers have built a microscopic device that could supply power for decades to remote sensors or implantable medical devices by drawing energy from a radioactive isotope. The device converts the energy stored in the radioactive material directly into motion. It could directly move the parts of a tiny machine or could generate electricity in a form more useful for many circuits than has been possible with earlier devices. This new approach creates a high-impedance source (the factor that determines the amplitude of the current) better suited to power many types of circuits, says Amit Lal, Cornell assistant professor of electrical and computer engineering.
October 16th, 2003