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) Central Electricity Board was established, the national grid created and the supply of electricity standardised. He was made GBE in 1925. In 1928 he began introducing major new electricity power systems in the West of England with his friend and then colleague, Dr John A. Purves. He was awarded the Faraday Medal for 1938 by the Institution of Electrical Engineers (now the Institution of Engineering and Technology). He died after an operation at the London Clinic in 1938. He had married Annie Glendenning Quick of Biscovey, Cornwall, with whom he had at least one son. John Snell (electrical engineer) Sir