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
David Davies (electrical engineer) (IEE) 1996-2001, President of the Royal Academy of Engineering He has subsequently been Chairman of Railway Safety, a non executive director of Lattice plc, a non-executive director of The ERA Foundation, Chairman of the Hazards Forum (2002-2010), and safety advisor to the Board of National Grid plc. The Sir David Davies building at Loughborough University, housing the electrical engineering department, is now named after him. David Davies (electrical engineer) Sir David Evan Naunton Davies , known as Den Davies or David "DEN" Davies, (born 1935) is a British electrical engineer and educator. He was knighted for services to science in