This was from a FB comment I made in Sept 2016.
Watson Fixer
There was nothing false about Edison’s legacy, unless you consider electrocuting elephants false. Many if not most of Edison’s ideas failed to become inventions. But his invention factory was so prolific that the successful inventions were large in number and importance.
In one of Edison’s experiments with the light bulb, he put a metal plate inside of the bulb. He found that the electric current could flow from the filament to the plate, but not from the plate to the filament. This thermionic emission (November 15, 1883, U.S. patent 307,031, the first US patent for an electronic device) became the basis for all of electronics for the first half of the 20th century. And if you don’t believe me, just go look up thermionic emission or the Edison Effect.
This thermionic emission is the grandfather of all modern electronics – everything.