Control grid Control grid The control grid is an electrode used in amplifying thermionic valves (vacuum tubes) such as the triode, tetrode and pentode, used to control the flow of electrons from the cathode to the anode (plate) electrode. The control grid usually consists of a cylindrical screen or helix of fine wire surrounding the cathode, and is surrounded in turn by the anode. The control grid was invented by Lee De Forest, who in 1906 added a grid to the Fleming valve (thermionic diode) to create the first amplifying vacuum tube, the Audion (triode). In a valve, the hot cathode emits
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