Radio receiver crude triode, was invented in 1906 by Lee De Forest as a more sensitive detector for radio receivers, by adding a third electrode to the thermionic diode detector, the Fleming valve. It was not widely used until its amplifying ability was recognized around 1912. The first tube receivers, invented by De Forest and built by hobbyists until the mid 1920s, used a single Audion which functioned as a grid-leak detector which both rectified and amplified the radio signal. There was uncertainty about the operating principle of the Audion until Edwin Armstrong explained both its amplifying and demodulating functions in a
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