HISTORY II           

1904: British engineer John Ambrose Fleming invents and patents the thermionic valve, the first vacuum tube. With this advance, the age of modern wireless electronics is born.

Although the Supreme Court eventually invalidated Fleming's U.S. patent -- ruling that the technology he used for his invention was already known -- he remains the acknowledged inventor of the vacuum tube, a diode (having two electrodes) that would have far-reaching applications. The tube was standard equipment in radio receivers, radar sets, early television sets and other forms of electronic communication for at least half a century, until it was replaced by solid-state electronicsin the mid-20th century.

The principle of thermionic emission, essentially the transmission of a charged current using a heated conductor, was certainly well-understood before Fleming incorporated it into his tube. It was first reported in 1873, and a number of other engineers and physicists -- including Thomas Edison -- had experimented with it.

Fleming's vacuum tube, however, represented a major breakthrough in the technology.

For his work, Fleming received a knighthood in 1929 and was awarded the Medal of Honor by the Institute of Radio Engineers (now the Institute of Electrical and Electronics Engineers) in 1933.

Fleming lived long enough to see the fruits of his labor literally save Britain during World War II. Radar sets using Fleming's diodes proved decisive in the Battle of Britain, allowing a relatively small number of British fighter planes to effectively turn back the Luftwaffe's onslaught against the home island.

Fleming died in 1945 at the age of 95.

John Ambrose Fleming

Rogers was born on June 21, 1900, in Toronto, Ontario. His father, businessman Albert Stephen Rogers (1860–1932),[1] was a director of Imperial Oil (after his Rogers Queen City Oil Company was bought out) and formerly a partner in Samuel and Elias Rogers Coal Company (later Elias Rogers and Company), founded in 1876 by his Quaker father (Samuel Rogers) and uncle Elias Rogers (1850-1920[3]) Elias served as a Toronto alderman for St. Lawrence Ward in 1887.[4] The family descends from Timothy Rogers (1756–1834), a Quaker leader who founded Newmarket and Pickering in what is now Ontario.

Rogers first became interested in radio when he saw a receiver at age 11. By 1913, he was noted in local newspapers for his skill at operating a radio station, which at the time was an impressive technical accomplishment. Rogers worked as a radio officer on Great Lakes passenger ships during the summers of 1916-1919 inclusive. In 1921, Rogers operated the only Canadian (and only spark-gap) station to successfully compete in the first amateur trans-Atlantic radio competition. Rogers held the amateur radio call sign 3BP, and joined the Canadian chapter of the American Radio Relay League in 1921.

In the early 1920s, radio transmitters and receivers ran on large and expensive batteries to provide the high voltages needed for the vacuum tubes used. Early attempts at producing a radio receiver to operate on household alternating current were unsuccessful, since tubes designed for the low current supply from batteries were unsatisfactory when operated on 25- or 60-hertz alternating current. The batteries were also extremely large and bulky.


John Ambrose Fleming