1883 AD to 1906 AD |
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| In 1879, the legendary American inventor Thomas Alva Edison publicly exhibited his incandescent electric light bulb for the first time. (If you ever happen to be in Dearborn, Michigan, you should take the time to visit the Henry Ford Museum, which happens to contain the world's largest and most spectacular collection of light bulbs.) |
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| Edison's light bulbs employed a conducting filament mounted in a glass bulb from which the air was evacuated leaving a vacuum. Passing electricity through the filament caused it to heat up enough to become incandescent and radiate light, while the vacuum prevented the filament from oxidizing and burning up. | ||
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| Edison continued to experiment with his light bulbs and, in 1883,
found that he could detect electrons flowing through the vacuum from the lighted filament
to a metal plate mounted inside the bulb. This discovery subsequently became known as the Edison Effect. Edison did not develop this particular finding any further, but an English physicist, John Ambrose Fleming, discovered that the Edison Effect could also be used to detect radio waves and to convert them to electricity. Fleming went on to develop a two-element vacuum tube known as diode. |
In 1906, the American inventor Lee de Forest introduced a
third electrode called the grid into the vacuum tube. The resulting triode could be used as both an amplifier and a switch, and many of the
early radio transmitters were built by de Forest using these triodes (he also presented
the first live opera broadcast and the first news report on radio). De Forest's triodes revolutionized the field of broadcasting and were destined to do much more, because their ability to act as switches was to have a tremendous impact on digital computing. |
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| These notes are abstracted from the book Bebop BYTES Back (An Unconventional Guide to Computers) Copyright Information |
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