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
Bjork–Shiley valve Bjork–Shiley valve The Björk–Shiley valve is a mechanical prosthetic heart valve. The valve was co-invented by American engineer Donald Shiley and Swedish heart surgeon Viking Björk. Beginning in 1971, it has been used to replace aortic valves and mitral valves. It was the first successful tilting-disc valve. It was manufactured first by Shiley Laboratories, then later by Pfizer after that company purchased Shiley. One model of the Bjork–Shiley valve became the subject of a famous lawsuit and recall after it was shown to malfunction. The Björk–Shiley valve consists of a single carbon-coated disc in a metal housing. The disc is