Radio receiver crude triode, was invented in 1906 by Lee De Forest as a more sensitive detector for radio receivers, by adding a third electrode to the thermionic diode detector, the Fleming valve. It was not widely used until its amplifying ability was recognized around 1912. The first tube receivers, invented by De Forest and built by hobbyists until the mid 1920s, used a single Audion which functioned as a grid-leak detector which both rectified and amplified the radio signal. There was uncertainty about the operating principle of the Audion until Edwin Armstrong explained both its amplifying and demodulating functions in a
Xiaodong Wang (electrical engineer) Xiaodong Wang (electrical engineer) Xiaodong Wang () is an information theorist and professor of Electrical Engineering at Columbia University. He earned a BS degree in electrical engineering and applied mathematics from Shanghai Jiaotong University, an MS degree in electrical and computer engineering from Purdue University, and a PhD from Princeton University in electrical engineering. He formerly served as assistant professor of Electrical Engineering at Texas A&M University before he joined Columbia as an assistant professor in January 2002. He is a Fellow of IEEE and an ISI Highly Cited author. He has won numerous prestigious awards, among them the National