Alexander Graham Bell

220px-Alexander_Graham_BellAlexander Graham Bell (Scottish; March 3, 1847 – August 2, 1922) Scientist and inventor. He is widely believed to be the inventor of the telephone system, though there were many at the time working on similar systems. Antonio Meucci and Elisha Gray (the founder of the Western Electric Manufacturing Company) also made significant contributions, and can be argued to be inventors of the telephone as well. While in his twenties, and living in Canada, Bell designed a piano which could transmit its music electrically. He continued his research at Boston University and produced a working telephone which could transmit the human voice as well as musical sounds. On March 7, 1876, the U.S. Patent Office granted him Patent Number 174,465 covering “the method of, and apparatus for, transmitting vocal or other sounds telegraphically … by causing electrical undulations, similar in form to the vibrations of the air accompanying the said vocal or other sound”. Bell had many other patented inventions as well. There were eighteen patents granted in his name alone and twelve that he shared with his collaborators. These included fourteen for the telephone and telegraph, four for the photophone, one for the phonograph, five for aerial vehicles, four for hydro-airplanes, and two for a selenium cell. The photophone was a precursor to our modern fiber optic communication system. It enabled the transmission of sound over a beam of light, and was developed together with Charles Sumner Tainter. The device employed light-sensitive cells of crystalline selenium, which have the property that its electrical resistance varies inversely with the intensity of illumination. The beam of light was modulated through the use of a vibrating mirror or rotating disk. Today we use an electronically modulated solid-state laser, and send the beam through glass fiber optic cables rather than line-of-sight through the air. Otherwise the principle is the same as what we use now. Bell is also credited with the invention of the metal detector in 1881. The device was hurriedly put together in an attempt to find the bullet in the body of U.S. President James Garfield after his attempted assassination. Read more…

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