Thomas Edison

Thomas Alva Edison is considered one of the greatest inventors in history. He was born in Milan, Ohio on February 11, 1847 and died in 1931. During his life he patented 1,093 inventions. Many of these inventions are in use today and changed the world forever. Some of his inventions include telegraphy, phonography, electric lighting and photography. His most famous inventions were the phonograph and the incandescent light bulb.

Edison did some of his greatest work at Menlo Park. While experimenting on an underwater cable for the automatic telegraph, he found that the electrical resistance and conductivity of carbon varied accordingly to the pressure it was under. This was a major theoretical discovery, which enabled Edison to invent a "pressure relay" using carbon rather than magnets, which was the usual way to vary and balance electrical currents. In February of 1877 Edison began experiments designed to produce a pressure relay that would amplify and improve the audibility of the telephone, a device that Edison and others had studied but which Alexander Graham Bell was the first to patent, in 1876. By the end of 1877 Edison had developed the carbon-button transmitter that is still used today in telephone speakers and microphones.

Many of Thomas Edison’s inventions including the carbon transmitter were in response to demands for new products and improvements. In 1877, he achieved his most unique discovery, the phonograph. During the summer of 1877 Edison was attempting to devise for the automatic telegraph a machine that would transcribe a signals as they were received into a form of the human voice so that they could then be delivered as telegraph messages. Some researchers had theorized that each sound, if it could be graphically recorded, would produce a distinct shape resembling short hand, or phonography, as it was known then. Edison hoped to make this concept real by employing a stylus-tipped carbon transmitter to make impressions on a strip of paraffined paper. To his amazement, the barley visible indentations generated a vague sound when the paper was pulled back beneath the stylus.

In December 1877 Edison unveiled the tinfoil phonograph, which replaced the strip of paper wrapped in tinfoil. Many people would not believe what they were hearing including a leading French scientist who declared it to be a trick device of a ventri...

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...ed whether something might be done, only how.

Edison’s career, the fulfillment of the American dream of rags-to-riches through hard work and intelligence, made him a folk hero to his countrymen. In temperament he was an uninhibited egotist, at once a tyrant to his employees and their most entertaining companion, so that there was never a dull moment with him. He was charismatic and courted publicity, but he had difficulty socializing and neglected his family. His shafts at the expense of the "long-haired" fraternity of theorists sometimes led formally trained scientists to depreciate him as anti-intellectual; yet he employed as his aides, at various times a number of eminent mathematical physicists, such as Nicole Tesla and A.E. Kennelly. The contradictory nature of his forceful personality, as well as such eccentricities as his ability to catnap anywhere, contributed to his legendary status. By the time he was in his middle 30s Edison was said to be the best-known American in the world. When he died he was the venerated and mourned as the man who, more than any other, had laid the basis for the technological and social revolution of the modern electrical world.