Audion fidelity audio equipment. Audion The Audion was an electronic detecting or amplifying vacuum tube invented by American electrical engineer Lee de Forest in 1906. It was the first triode, consisting of an evacuated glass tube containing three electrodes: a heated filament, a grid, and a plate. It is important in the history of technology because it was the first widely used electronic device which could amplify; a small electrical signal applied to the grid could control a larger current flowing from the filament to plate. The original triode Audion had more residual gas in the tube than later versions and
Harold Rosen (electrical engineer) him with hands-on experience with radio communications and the then-new field of radars. In 1949, Rosen married Rosetta, and they had two sons, Robert (born 1950) and Rocky (born 1966). Rosetta died in 1969. In 1984 he married Deborah Castleman, a satellite systems engineer also working at Hughes Aircraft Company. Rosen died on January 30, 2017 due to complications from a stroke, aged 90. Rosen has more than 80 patents. He was a Fellow of the IEEE and the AIAA, and a member of the National Academy of Engineering. Rosen has received numerous awards which include: Harold Rosen (electrical engineer)