A MISSED OPPORTUNITY

Hawke's Bay Tribune, Volume XIX, Issue 305, 11 December 1929, Page 10

A MISSED OPPORTUNITY

Shortly after Edison's invention of the electric light bulb fifty years ago he began a series of experiments with various arrangements of the filaments in the bulbs. In one experiment, in IS-'it). tne invwiwi incrodi oed an extra element within the lb. 13 chance he happened to connect » galvanometer to a wire leading to the plate and noted a flow of negative current. His first thought was that it was introduced by the negative pole connected to the filament but further experimentation revealed, regardless di the position of the plate and its relation to the positive or negative wire of the filament, its current was always negative.

The inventor, who was busy with other problems, merely noted the phenomena down in a notebook, and continued his experiments along other lines. The discovery was known as the “Edison effect,” and to-day is the sole principle of tlfe modern vacuum valve. It virtually was the discovery of the flow of electrons from a heated cathode to an anode within a vacuum. To-day there are over 100,000.060 vacuum tubes in use in the United States and probably as many more in the remainder of the world which employ the principle of the fundamental discovery of Edison. First vacuum tubes invented by Dr. Flemming, British inventor, were practically duplicates of Edison’s electric lamp with a plate element.

it was Dr. Flemming who first discovered the effect of electron emission, and its relation and value io radio reception. Dr. DeForcst, an early experimenter, also made many experiments and discoveries alopg this line, and was the first to devise ft means of the electron flow from the cathode to the anode by introducing a third element known to-day as the •grid.”