History of electronic engineering on to develop the first practical and widely used radio wave based communication system. In 1904, John Ambrose Fleming, the first professor of electrical Engineering at University College London, invented the first radio tube, the diode. Then, in 1906, Robert von Lieben and Lee De Forest independently developed the amplifier tube, called the triode. Electronics is often considered to have begun with the invention of the triode. Within 10 years, the device was used in radio transmitters and receivers as well as systems for long distance telephone calls. The invention of the triode amplifier, generator, and detector made audio communication
Vienna valve trombone Vienna valve trombone Vienna valve trombones use Vienna Valves which were one of the earliest valve systems used in wind instruments. These valves were first publicly reported in 1815 and valved trombones were first introduced in the late 1830s. The Vienna valve was invented in Leipzig in 1821 by Sattler, predating the Perinet valve and rotary valve used in France and Germany (and in all French horns). The Vienna Valves (or Double Valves) have two short parallel pistons connected at the bottom by a bar that is moved by a long rod or linkage connected to the spring-loaded finger plate.