Control grid Control grid The control grid is an electrode used in amplifying thermionic valves (vacuum tubes) such as the triode, tetrode and pentode, used to control the flow of electrons from the cathode to the anode (plate) electrode. The control grid usually consists of a cylindrical screen or helix of fine wire surrounding the cathode, and is surrounded in turn by the anode. The control grid was invented by Lee De Forest, who in 1906 added a grid to the Fleming valve (thermionic diode) to create the first amplifying vacuum tube, the Audion (triode). In a valve, the hot cathode emits
David Davies (electrical engineer) 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 1994. 1985-1988: Head of the Department of Electronic and Electrical Engineering at University College London (UCL), and holder of the Pender Chair, having already been lecturing there, in "Communications Systems", for many years prior to that. 1986-1988: Vice-Provost of University College London 1988-1993: Vice Chancellor of Loughborough University 1993–1999: Chief Scientific Adviser for the Ministry of Defence 1994-1995: President of the Institution of Electrical Engineers