Valve amplifier thermionic valves. The simplest valve was invented by John Ambrose Fleming while working for the Marconi Company in London in 1904 and named the diode, as it had two electrodes. The diode conducted electricity in one direction only and was used as a radio detector and a rectifier. In 1906 Lee De Forest added a third electrode and invented the first electronic amplifying device, the triode, which he named the "Audion". This additional "control grid" modulates the current that flows between cathode and anode. The relationship between current flow and plate and grid voltage is often represented as a series
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