Amplifier by their physical placement in the signal chain; a preamplifier may precede other signal processing stages, for example. The first practical electrical device which could amplify was the triode vacuum tube, invented in 1906 by Lee De Forest, which led to the first amplifiers around 1912. Today most amplifiers use transistors. The first practical device that could amplify was the triode vacuum tube, invented in 1906 by Lee De Forest, which led to the first amplifiers around 1912. Vacuum tubes were used in almost all amplifiers until the 1960s–1970s when the transistor, invented in 1947, replaced them. Today, most amplifiers
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