Edison, Thomas Alva (1847-1931), US inventor and physicist, considered ???he most prolific inventor the world has ever seen?? famous for inventing or improving devices such as the phonograph, the incandescent electric light bulb and the motion-picture camera, as well as as improving the telegraph and telephone. He founded several laboratories and companies, and filed over 1000 patents. He invented an electric vote-recording machine and a paper ticker-tape for stock exchange prices. Other work included his direct current (DC) electrical distribution systems which was replaced by the cheaper and more efficient polyphase alternating system (AC) of Nikola Tesla. In 1901, Edison created a nickel-alkaline battery for the somewhat slow and restricted electric automobiles his factory was producing. Not all his inventions were successful, but failure did not discourage him.