Valve amplifier thermionic valves. The simplest valve was invented by John Ambrose Fleming while working for the Marconi Company in London in 1904 and named the diode, as it had two electrodes. The diode conducted electricity in one direction only and was used as a radio detector and a rectifier. In 1906 Lee De Forest added a third electrode and invented the first electronic amplifying device, the triode, which he named the "Audion". This additional "control grid" modulates the current that flows between cathode and anode. The relationship between current flow and plate and grid voltage is often represented as a series
Jim McDonald (electrical engineer) Jim McDonald (electrical engineer) Sir James McDonald FREng FRSE FInstP FIET is a British educator, serving as Principal and Vice-Chancellor of the University of Strathclyde since 2009. He is also a visiting professor at NYU Tandon School of Engineering. After seven years of work within the UK Electricity Supply Industry, McDonald joined Strathclyde University in 1984 and became Professor of Electrical Power Systems in 1993. In 2001 he was invited to deliver the MacMillan Memorial Lecture to the Institution of Engineers and Shipbuilders in Scotland. He chose the subject "Electric Propulsion in Marine Applications: An Electrical Engineer's Viewpoint". In 2006