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
Gary Birch (electrical engineer) Gary Birch (electrical engineer) Dr. Gary Birch, is a Canadian Paralympian, an expert in Brain-Computer Interface (BCI) technology and Executive Director of the Neil Squire Society. In 1975, Dr. Birch was involved in an automobile accident which resulted in injuries to the C6 and C7 area of his spine making him a low-level quadriplegic. He was one of the original players of Murderball (wheelchair rugby), and won several medals in the 1980 Summer Paralympics in the Netherlands. In 2008, he was appointed an Officer of the Order of Canada. He continues to champion accessibility through his Research and Development work