10 Facts About Fleming valve

Fleming valve, called the Fleming oscillation valve, was a thermionic valve or vacuum tube invented in 1904 by English physicist John Ambrose Fleming as a detector for early radio receivers used in electromagnetic wireless telegraphy.

The Fleming valve was the forerunner of all vacuum tubes, which dominated electronics for 50 years.

At high voltages, the Fleming valve could become unstable and oscillate, but this occurred at voltages far above those normally used.

Fleming valve was the first practical application of thermionic emission, discovered in 1873 by Frederick Guthrie.

In 1901 Fleming valve designed the transmitter used by Guglielmo Marconi in the first transmission of radio waves across the Atlantic from Poldhu, England, to Signal Hill, St John's, Newfoundland, Canada.

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In 1904 Fleming valve tried an Edison effect bulb for this purpose, and found that it worked well to rectify high frequency oscillations and thus allow detection of the rectified signals by a galvanometer.

The Fleming valve was used by the Marconi company in its shipboard receivers until around 1916, when it was replaced by the triode.

Fleming valve proved to be the start of a technological revolution.

Fleming sued De Forest for infringing his valve patents, resulting in decades of expensive and disruptive litigation, which were not settled until 1943 when the United States Supreme Court ruled Fleming's patent invalid.

Later, when vacuum tube equipment began to be powered from wall power by transformers instead of batteries, the Fleming valve was developed into a rectifier to produce the DC plate voltage required by other vacuum tubes.