What device, invented by Peter Cooper Hewitt in 1902 and obsolete by 1975 with the introduction of devices such as the silicon diode and thyristor, converts alternating current to direct current by means of putting electricity through vapor?
Peter Cooper Hewitt mercury. This was the fluorescent lamp, which is now one of the most widely used lamps in the world. In 1902 Hewitt developed the mercury arc rectifier, the first rectifier that could convert alternating current power to direct current without mechanical means. It was widely used in electric railways, industry, electroplating, and high-voltage direct current (HVDC) power transmission. Although it was largely replaced by power semiconductor devices in the 1970s and 1980s, it is still used in some high power applications. In 1903, the degree of Honorary Doctorate of Science was conferred upon him by the Columbia University in recognition
Peter Cooper Hewitt Peter Cooper Hewitt Hewitt was born in New York City, the son of New York City Mayor Abram Hewitt and the grandson of industrialist Peter Cooper. He was educated at the Stevens Institute of Technology and the Columbia University School of Mines. In 1901 he invented and patented a mercury-vapor lamp; a gas-discharge lamp that used mercury vapor produced by passing current through liquid mercury. His first lamps had to be started by tilting the tube to make contact between the two electrodes and the liquid mercury; later he developed the inductive electrical ballast to start the tube. The efficiency