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
Don Carpenter (electrical engineer) dynamics and for development and use of whistler-mode waves as diagnostic probes of the magnetosphere". He was elected a Fellow of the American Geophysical Union in 2002. Don Carpenter (electrical engineer) Donald L. Carpenter is a Space Scientist, Professor (Research) Emeritus in the Electrical Engineering Department at Stanford University. He co-discovered the sharp dropoff in the plasmasphere surrounding Earth. Known as co-discoverer of the “knee,” or sharp dropoff (later called the plasmapause) in the radial profile of the dense plasma cloud (later called the plasmasphere) that surrounds the Earth to typical equatorial distances of several Earth radii. Carpenter was awarded