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
Alexander Russell (electrical engineer) was awarded the Faraday Medal of the Institution of Electrical Engineers. He died in 1943 after a long illness. He had married Edith, the daughter of H.B.Ince, MP, and had a son and a daughter. Alexander Russell (electrical engineer) Alexander Russell, FRS (15 July 1861 – 14 January 1943) was a Scottish electrical engineer and educator. He was born in Ayr, Scotland and educated at Glasgow University (gaining an MA in Mathematics and Physics) and Caius College, Cambridge. He was later (in 1924) awarded a doctorate. After teaching mathematics at Cheltenham College and the Oxford Military College, he took a