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Thomas Alva Edison


  Milan (Ohio) 11.February.1847-  West Orange (New Jersey) 18.October.1931
1879 Microphone coal


Railway Boy to 12 years, then long telegrapher    the railway   lines Americans, self-taught.  In 1876 it creates the laboratory of Menlo Park, still  today working. After two years from this creation it was dedicated to the problem of the light,  already was begun    the search in Europe in this   field, in   the 1860  Swan was already successful to construct to a light bulb electrical worker having for filament a coal strip    , but its duration was too much short. Edison resolved the problem in practical way carbonating  a bamboo  filament    obtained    a extended life   of  the lamp,  thanks  also  to the improvement of the pumps   to high empty that were available in 1878. Edison realized its lamp electrical worker 21 October 1879,  after two months illuminated the roads of the city of Menlo Park.

November 11, 1878 introduces license question that obtains 9 December 1879  Carbon telephone  (cap to coal) N° 222,390 with which the telephone systems I obtain   great improvement in the transmission and audio reception.