The first achievement after Maxwell’s theory was the invention of the electric bulbs by another genius Thomas Edison. The lighted the world by his electric bulbs. He invented numerous electrical devices and contributed the most to the consumer electrics. He was mainly using DC and was the greatest advocate of the use of DC. But one of his contemporaries Nicola Tesla had something different in his mind. He used his brain to make AC popular. He invented the induction motor and proved that AC can be used more efficiently than DC. After some years with the help of Westinghouse he took the tender of the Niagara Project and started generating AC. Another big thing had happened at the same time while Edison was trying to light an electric bulb. That was the “Edison effect” or the thermoionic effect. Edison found that in a closed environment even without the physical contact of wires there exist a small current through them when they are heated to a sufficiently high temperature.
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