Fleming Valve Vacuum Tube
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Fleming valve - Wikipedia, the free encyclopedia
The Fleming valve was the first practical application of the " ... reading Fleming's 1905 paper on his oscillation valve, American ... Fleming Valve, 1904 ...
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Fleming
Fleming calls the device a valve because it allows electrical currents to pass ... Fleming made many adjustments to his valve over the next few years. ...
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Fleming Valve
The Fleming Oscillation Valve was the first practical application of the Edison ... The Fleming Valve is considered by most wireless historians to be the ...
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IEEE - IEEE History Center: Fleming Valve, 1904
fleming diode, valve, engineering milestone ... After reading Fleming's 1905 paper on his oscillation valve, American engineer ...
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Fleming Valve
The Fleming Valve. The Fleming Valve is a diode that was used as a radio signal detector in the ... In 1899, John Ambrose Fleming, who worked for the British ...
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Professor Sir John Ambrose Fleming :: Radio-Electronics.Com
The life of Professor Sir John Ambrose Fleming, inventor of the oscillation diode valve or vacuum tube. Some say he is the founder of electronics.
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Tube Amplifiers by Milbert Amplifiers
Vacuum tube car stereo equipment since 1986 ... Fleming patented the device, ultimately named the "Fleming valve," "oscillation ...
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John Ambrose Fleming: Biography from Answers.com
Sir John Ambrose Fleming British physicist and electrical engineer (1849-1945) Fleming, who was born ... "Fleming Valve, 1904," IEEE History Center Web site. ...
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History of the Vacuum Tube :: Radio-Electronics.Com
The history of the vacuum tube or thermionic valve from the first observations of the Edison Effect through early developments such as Fleming's Oscillation Valve ...
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The Fleming valve, also called the Fleming oscillation valve, was a vacuum tube diode invented by John Ambrose Fleming and used in the earliest days of radio communication. As the first vacuum tube, the IEEE has described it as "one of the most important developments in the history of electronics", IEEE History Center: Fleming Valve, 1904 and it is on the List of IEEE Milestones for electrical engineering.

Description Applications The Fleming valve was the first practical application of the "Edison effect" (thermionic emission) discovered in 1883 by Thomas Edison shortly after his invention of the incandescent light bulb, that is, the emission of electrons by a lamp's heated filament to a nearby metal plate. Edison was granted a patent for this device as part of an electrical indicator in 1884, but did not hit upon any practical use. Professor Fleming of University College London consulted for the Edison Electric Light Company from 1881-1891, and subsequently for the Marconi Wireless Telegraph Company.

In 1901 Fleming designed a transmitter for Guglielmo Marconi to attempt transmission of radio waves across the Atlantic from Poldhu, England, to Nova Scotia, Canada. The distance between the two points was about 3,500 kilometres (2,100 miles). Although widely heralded as a great scientific advance, there was also some skepticism about this claim, in part because the signals had only been heard faintly and sporadically. In addition, there was no independent confirmation of the reported reception, and the transmission, which merely consisted of the three dots of the Morse code letter S sent repeatedly, came from a transmitter whose signals were difficult to differentiate from the noise made by atmospheric static discharges. (A detailed technical review of the early transatlantic work appears in John S. Belrose's work of 1995.) Fessenden and Marconi: Their Differing Technologies and Transatlantic Experiments During the First Decade of this Century The receptions of signals were difficult to detect with a galvanometer. Fleming researched on a way that he could get the received signal to flow in only one direction, its oscillations could be detected with less trouble. Radio Communications: A Brief Synopsis John Ambrose Fleming (1849-1945) By W A Atherton, Published in Wireless World August 1990Do note that Nikola Tesla had already discovered that oscillations, damped or undamped, could be detected after being made to flow one direction or being developed as alternating in direction. For more, see "Nikola Tesla on His Work With Alternating Currents and Their Application to Wireless Telegraphy, Telephony and Transmission of Power : An Extended Interview". ISBN 1893817016

In 1904 Fleming 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. On November 16, 1904, he applied for a US patent for what he termed an oscillation valve. This patent was subsequently issued as number 803,684 and found immediate utility in the detection of messages sent by Morse code.

Oscillation valves The Fleming valve proved to be the start of a technological revolution. After reading Fleming's 1905 paper on his oscillation valve, American engineer Lee DeForest in 1906 created a three-element vacuum tube (the Audion tube) by adding a modulation grid. It could act as an amplifier and oscillator as well as detector. De Forest quickly refined his device into the triode, which was then central to the creation of long-distance telephone and radio communications, radars, and early digital computers. Similarities and differences between the Fleming valve and DeForest's triode caused decades of expensive and disruptive litigation, which were not settled until 1943 when the United States Supreme Court ruled Fleming's patent invalid.The Supreme Court invalidated the patent because of an improper disclaimer and later maintained the technology in the patent was known art when filed. For more see, Misreading the Supreme Court: A Puzzling Chapter in the History of Radio. Mercurians.org.

References and notes Citations

Patents Issued

• - Instrument for converting alternating electric currents into continuous currents (Fleming valve patent)

Cited by

• , Jan 7, 1910 : Fleming valve improvement by Roy Alexander Weagant
• , Apr 12, 1910 : John Ambrose Fleming patent
• , Mar 10, 1917 : Fleming valve improvement by R. A. Weagant
• , Jan 8, 1918 : Fleming valve improvement by R. A. Weagant
• , Sep 10, 1918 : Fleming valve improvement by R. A. Weagant
• , Dec 31, 1918 : Fleming valve improvement by R. A. Weagant
• , Jun 10, 1919 : Fleming valve circuit improvement by R. A. Weagant
• , May 4, 1920 : Fleming valve improvement by R. A. Weagant
• , Jul 27, 1920 : Inverter converter by Lewis W. Chubb
• , May 31, 1921 : Fleming valve improvement by R. A. Weagant
• , Jun 15, 1926 : Inverter converter by L. W. Chubb
• , May 1, 1928 : Fleming valve circuit improvement by Philip E. Edelman
• , Jun 7, 1949 : Electrode improvement by Harry L. Ratchford

External links

• IEEE History Center
• Spark Museum
• Reverse Time Page