You probably would not think of building a radio detector from a light bulb, but that is what Ambrose Fleming did 100 years ago in 1904. The result was what he called the 'oscillation valve', now better known as the thermionic diode. It was only two years later when Lee De Forest added a third electrode to make the first primative triode. These two classic inventions led to a fight between the two inventors, but they also led to the now-vast, worldwide industry we call electronics.