The Evolution of an Electronic Miracle
The microprocessor evolved over the course of many years of research, and people all over the world enjoy the benefits of this electronic miracle. It is difficult to think of anything that has affected modern life more than this invention. Cellular phones, wristwatches, calculators, automobiles, stereos, televisions, and computers are just a few of the thousands of electronic devices that have a microchip at the heart of its operation. Over the years, three major breakthroughs occurred to accelerate the birth of the microprocessor: the vacuum tube, the transistor, and the integrated circuit.
The Vacuum Tube
American physicist Lee De Forest invented the vacuum tube in 1906. However, one must look back to 1879 when Thomas Edison first revealed the incandescent electric light bulb to understand how De Forest developed his idea. Edison 's invention consisted of a conducting filament mounted in a glass bulb. Electricity passing through the filament caused it to heat up and created a vacuum that prevented the filament from oxidizing and burning up. In 1883, Edison detected electrons flowing through the vacuum from the lighted filament to a metal plate mounted inside the bulb. This became known as the Edison Effect, but he did not develop this particular discovery any further. However, British physicist John Fleming found that the Edison Effect also detected radio waves and converted them to electricity. In 1904, Fleming first showed off his two-element vacuum tube known as the Fleming diode that converted an alternating current (AC) signal into direct current (DC) (Kuphaldt).
The Fleming diode consisted of an incandescent light bulb with an extra electrode inside. Electrons boiled off the surface of the metal plate and into the vacuum inside the bulb as the filament became white-hot. When the extra electrode became more positive than the filament, a direct current flowed through the vacuum proving
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