“Unlocking the Future: How a Simple Discovery Revolutionized Technology and Changed Our Lives Forever”
In the first half of the 20th Century, electronics design was dominated by one key piece of technology: the vacuum tube.
During Thomas Edison and his team’s thousands of experiments trying to create an economically viable incandescent lightbulb, there was a rather insanely revolutionary and far more unique device Edison accidentally invented in parallel with the lightbulb that was just one of his lightbulbs with a slight twist. But unfortunately for Edison, he did not realize the implication of what he’d just made in one of his thousands of tests, and how revolutionary it could be if refined a bit, and in the right applications. Because of his failure to realize any of this, nor be the one to perfect it for commercial use, despite his patent for the device, Edison is almost never given credit for his contribution on this world changing invention. Which is unsurprising as, as is a theme you’re probably picking up on, it’s the person who ultimately did the thing in its perfected commercial form, rather than was the first to come up with the thing, that usually gets credit in popular history.
On this one, enter English physicist John Ambrose Fleming, who was an advisor to Edison Electric Light. He would be inspired by Edison’s device to create his revolutionary Fleming valve vacuum tube in the early 20th century.
But going back to Edison’s original device, at one point during his experiments on the lightbulb, he and his staff were trying to figure out why carbon from the filament seemed to be jumping across the vacuum to the walls of the bulb. Clearly some current flow was involved. So in order to try to figure out what was going on here, Edison created a special bulb with a third electrode placed in between the legs of the filament, and then connected that to a galvanometer to measure the current. What he found was that if, relative to the filament, the plate was put at a negative potential, there would be no current between the plate and the filament. However, if the plate was at a positive potential, and the filament heated up enough, there would be a large current flow between the filament to the plate through the vacuum. Importantly in this, the electrons can only flow one way, from the hot element to the cold one, creating a rudimentary diode.
