Scientists say they see exciting potential for the world's first high-temperature superconducting transistor in the development more advanced supercomputers, microwave components and other electronics. The new transistor was developed at the University of Wisconsin and Sandia National Laboratories in Albuquerque, N.M., and operates at a relatively high temperature of minus 340 degrees Fahrenheit, the scientists said Monday. While superconductive compounds that function at similarly high temperatures have been known for years, the transistor marks the first successful attempt to use such materials to create a transistor. The Department of Energy also backed the project, which now has advanced to the installation of the transistor into a functioning electronic circuit. Transistors, often the size of pinheads, function in supercomputers and other electronic devices as the switches that control current. They also are used to amplify signals from devices ranging from stereos to satellites. Superconductivity, the loss of all resistance to electrical current, occurs in dozens of materials when they are chilled to minus 452 degrees Fahrenheit, or close to absolute zero. Devices that become superconductive at higher, more easily achievable temperatures would allow more practical applications and could open the way to faster supercomputers, microwave components and other electronics products. The new transistor is etched in a thin film of thalium and superconducting copper oxide and is chilled to the temperature of liquid nitrogen. While you still ``can't keep it in your shirt pocket,'' it gives scientists more flexibility because it operates at a higher temperature, said electrical engineering Professor James B. Beyer, who directed the project along with Professor James E. Nordman and university graduate Jon Martens. The new transistor intrigues scientists partly because it functions far differently from conventional transistors. Conventional transistors use alteration in the voltage to control current. The new transistor uses changes in the current to control voltage. Ken Frazier, a Sandia spokeesman, said the new transistor may serve as a bridge between circuitry that functions at room temperature and circuitry being developed using superconductivity close to absolute zero. But Nordman cautioned that scientists are still studying the new transistor and are far fro determining its applications. ``The transistor was invented in 1948, and we've been learning about it ever since,'' he said.