November 16th can be said to have been the 100th anniversary of electronics. On that day in 1904 Sir John Fleming patented the oscillation valve, later known as the Fleming tube. This first tube was a diode, and in a later improvement by engineer Lee DeForest, was turned into an amplifier.
This invention by Fleming was based on work laid out by his predecessors, one of which included Thomas Edison. Edison had patented the light bulb. One of the problems with his first bulb was that after a while the inside of the glass bulb would turn black. His initial guess, which we now know was wrong, was that carbon was being thrown off by the filament and adhering to the glass. He made several attempts to solve this problem. One of the attempts involved putting a second element in the bulb. He reasoned that if he would charge this second element positively the carbon atoms would be attracted to it. One observation was that there was a current flow between the two elements. He experimented further by charging the second element negatively. It was observed that no current flowed. Edison found the effect curious but did not see a market opportunity for the effect.
Several years later Fleming was also intrigued by this effect. He experimented further and perfected a one way electric valve. He realized that it was not carbon atoms being thrown off, but electrons. A parallel event helped Fleming recognize the importance of this intriguing effect. In 1901 the Marconi company made the first transatlantic radio transmission. Because Fleming was an acknowledged engineer he was hired as a consultant to improve the radio. It was on a November 16 in 1904 that Fleming recognized the market opportunity for the effect he had investigated. The tube could be used to rectify the radio signal thus making a more sensitive radio than was available using the electronics of the time.
The value of the patent though was not realized by Fleming. He spent most of the money in later years fighting patent battles. Three years later Lee DeForest patented an improvement to the Fleming valve, the three element tube. The three element tube, which DeForest called the Auditron, allowed amplification of a small signal or could be made to oscillate. Fleming?s original invention was also surpassed by so called ?cats whisker? detectors invented in 1906. These devices were cheaper and did not generate the heat of the Fleming tubes.