Aquila Children's Magazine The Electric Issue - Page 14

A REAL DING-DONG: EDISON, TESLA AND THE WAR OF CURRENTS In the late 19th century two great inventors engaged in a heated battle of wits, but who came out on top? Let’s take a look. EDISON One of these inventors was Thomas Edison. Born in the United States in 1847, he had already fallen out with another inventor, the Englishman Joseph Swan, over which of them had invented the electric light bulb*. But in 1883, the two joined forces to form the Edison and Swan Electric Light Company. One rivalry was settled, but another was just beginning. Enter Nikola Tesla (1856-1943). Tesla had been born in a village in present-day Croatia and his early life had been challenging, not least because of illness. He was still in his twenties when he arrived in the US in 1884, carrying only his own engineering genius and a letter of introduction to none other than, yep! You guessed it: Thomas Edison. The burning question of the day was this: How should we supply all the electric power that people need for lighting their towns, streets and homes? To his credit, Edison recognised the younger man’s brilliance. Here was someone who could work on an idea without needing to make models first, or conduct experiments, or even put pen to paper. Looking back, Tesla himself said: ‘I could do it all in my mind’. This was the best way, Tesla thought, because then he never lost sight of his inspiration, ‘the great underlying principle’ of what he wanted to create. For his part, Tesla admired Edison’s drive and determination, and worked with him during his early days in the US. And yet, when it came to the urgent problem – how to supply an efficient amount of energy – the two men disagreed completely. EDISON AND DIRECT CURRENT Edison wanted electricity to be distributed on the direct current (or DC) system. This is the kind produced by batteries. When they were first invented, these were the only sources of electric power. DC comes from a reaction that is easily contained. It is still used today for everything from torches to mobile phones but it has some disadvantages. Batteries produce a certain fixed amount of energy and then run out: they die, and need to be replaced or recharged. When Edison started building power plants on his system, he needed to use thick copper cables to conduct the electricity, and even then the current only ran for a short distance. Worse still, there was no way to vary the amount of power to suit different purposes. TESLA AND ALTERNATING CURRENT Tesla, on the other hand, supported the large-scale use of an alternating current (or AC) system of transmitting electrical energy. This involves a charge of electricity that changes back and forth regularly, flowing out along a circuit. This may sound more complicated but it is actually easier to run. The power can speed along thin wires for much greater distances. What is 14