Thomas Alva Edison

American inventor, whose development of a practical electric light bulb, electric generating system, sound recording device, and motion picture projector had profound effects on the shaping of modern society.

In 1879 Edison exhibited publicly his incandescent electric light bulb, his most important invention and the one requiring the most careful research and experimentation to perfect. In 1882 he developed and installed in New York City the world's first large central electric power station. In 1883 he observed the flow of electrons from a heated filament- the so-called Edison effect.