Audion 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 vacuum tubes; the
John Snell (electrical engineer) John Snell (electrical engineer) Sir John Francis Cleverton Snell, GBE (15 December 1859 – 6 July 1938) was a British electrical engineer and administrator. He was born in Saltash, Cornwall, the only son of Commander John Skinner Snell, RN and his wife Harriet Cleverton and educated at Plymouth Grammar School, Finsbury Technical College and King's College, London. After working for four years from 1885 with Messrs. Woodhouse and Rawson he was appointed in 1889 a resident engineer at Messrs. Crompton and Co., where he worked on electrical supply projects in London and Stockholm. From 1892 he worked as assistant to