Electric Mind Nikola Tesla, who turned on the world with his AC technology, talks about robots, cell phones, and the sacred fire of invention.By Marc J. Seifer and Michael BeharIn 1885, armed with an unproven new device, the alternating-current polyphase generator, Nikola Tesla set out to fight a crucial battle. His foe: Thomas Edison, the inventor/entrepreneur/public hero whose direct-current technology was distributing electricity to hundreds of US cities. But DC was flawed – because its current waned with distance, homes and factories had to be situated within a few thousand feet of generators. Using Teslas AC system, however, electricity could be transmitted for hundreds of miles.Still, Edisons stature gave DC the inside track. But Tesla had an influential backer, George Westinghouse, who in 1893 underbid Edison for the contract to light the Worlds Columbian Exposition in Chicago. Alternating current performed so well at the fair that the technological tide turned. Today, the worlds power grids are based on Teslas AC polyphase system.As for Tesla, a Croatian-born Serb who came to America as a young man, he had just begun to innovate. His inquiries anticipated hundreds of familiar devices and technologies, including lasers, cell phones, artificial intelligence and robots, and remote-control devices. Born in 1856 of a family with extraordinary longevity, Tesla once predicted he would live past age 140. Now, 142 years after he was born, he still has a lot to say.