Little Bits of History

Fleming Valve

Posted in History by patriciahysell on November 16, 2015
Oscillation valve

Oscillation valve Patent

November 16, 1904: John Ambrose Fleming invents an oscillation valve. It was also known as a two-electrode vacuum-tube rectifier, thermionic valve, vacuum diode, kenotron, thermionic tube, and the Fleming valve. Fleming was born in Lancaster, Lancashire, England in 1849 as the eldest of seven children. His father was a Congregational minister and Fleming remained a devout Christian all his life, even preaching on at least on occasion. In 1932 he helped to found the Evolution Protest Movement which is today called the Creation Science Movement and claims to be the oldest creationist movement in the world. He was home schooled until about age ten and showed an early interest in engineering. This was beyond his parents ability and so Fleming worked and studied until he could complete his educational goals. He married twice but remained childless.

The valve he created on this day had a carbon or tungsten filament lamp and he added a metal plate to insulate the filament. A wire was brought through the glass wall to a third terminal outside the bulb. When battery current was applied, the filament became incandescent and the space between the filament and the plate was found to conduct electrons in only one direction. The benefit of this unilateral conduction was that if the circuit used oscillating current, the current would become unidirectional and capable of actuating a telephone receiver. He had begun working with Guglielmo Marconi five years previously at The Marconi Company (a British telegraphy company founded by Marconi) and wrote to his former boss on November 30, telling him of the breakthrough.

Fleming patented his development and received US patent No. 803,684 on November 7, 1905. The patent was granted to Fleming of London but the assignor was Marconi Wireless Telegraph Company of America with headquarters in New Jersey. Eventually the United States Supreme Court invalidated the patent stating the technology was already well known prior to the patent application. The new tube, regardless of the Supreme Court’s judgment, is considered to have been the beginning of the electronics era and this, the first vacuum tube. The tube was used in radio receivers and radars for decades and only went out of use after the invention of solid state circuits.

Fleming taught at University College, London and had the Pender Chair position after it was endowed. The Chair is usually held by the head of the Department of Electronic and Electrical Engineering and remains intact. There have been ten men to take the position with Michael Pepper being the present holder. Fleming retired from University College in 1927 at the age of 77. By then, his tubes (modified and improved) were being used in televisions, another technology he believed in. He served as the first president of the Television Society. He died in 1945 at the age of 95 and bequeathed his considerable estate to Christian charities with a focus on those aiding the poor.

I’m not much into current electronic stuff, what I think of as lounge electronics, mumbling electronics. – Derek Bailey

I think I have this field around me that makes electronics work bad. It’s not like an entropy thing; it happens very quickly. – Cary Fukunaga

The new electronic independence re-creates the world in the image of a global village. – Marshall McLuhan

Certainly the advent of technology and electronic commerce has had an immense impact on the real estate industry. – Michael Oxley

Also on this day: The Fugitive? – In 1966, Dr. Sam Sheppard was finally acquitted of his wife’s 1954 murder.
UNESCO – In 1945, UNESCO was founded.
Wagons, Ho – In 1821, the first Santa Fe trail crossing was completed.
Sentenced – In 1849, Fyodor Dostoevsky was sentenced to death.
The Safe Airline – In 1920, Qantas was founded.

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