Audio power amplifier inside the chassis of the main product. The audio amplifier was invented around 1912 by Lee De Forest, made possible by his invention of the first practical amplifying electrical component, the triode vacuum tube (or "valve" in British English) in 1907. The triode was a three terminal device with a control grid that can modulate the flow of electrons from the filament to the plate. The triode vacuum amplifier was used to make the first AM radio. Early audio power amplifiers were based on vacuum tubes and some of these achieved notably high audio quality (e.g., the Williamson amplifier of
William Bryson (electrical engineer) had offices at 16 Queen Charlotte Street in Leith. He died on 9 July 1906. He is buried in Warriston Cemetery. The grave lies on the diagonal path joining the lower vaults to the sealed eastern entrance. The stone is currently (2018) vandalised and is lying on the ground in undergrowth. William Bryson (electrical engineer) William Alexander Bryson FRSE (2 March 1855 – 9 July 1906), was a Scottish electrical engineer. He was born on 2 March 1855, the son of Alexander Bryson and Elizabeth W. Gillespie. His grandfather was Robert Bryson. His mother died shortly after he was born,