# How Nikola Tesla changed the world? AC power

“I don’t care that they stole my idea, I care that they don’t have any of their own”, said by one of the greatest inventors to have ever lived, the Serbian inventor Nikola Tesla who developed the framework for modern-day electrical engineering. When Nikola Tesla began work at Edison’s DC (direct current) power plant in the United States, his new employer was not interested in his ideas for a new type of power called AC (alternating current). At the time DC was the only electrical supply, but it could only be transmitted across short distances before it lost power. To Edison, AC sounded like competition and he persuaded Tesla to work on improving his DC system by offering him a huge sum of money. But when Tesla had done what he had been asked, Edison reneged on his promise. Tesla resigned and returned to his AC power concepts. DC power is constant and moves in one direction and the resistance in wires causes it to lose power over distance. AC power does not have this problem as it varies in current so the resistance is less, and yet it varies in current so the resistance is less, and yet it delivers the same amount of power.

How AC current works?

In an atom, the negatively charged electrons are bound to the nucleus due to their electromagnetic attraction to the oppositely charged nucleus. But the electrons in the outer most shell called valence shell can sometimes become free due to external forces. These electrons that escape from the valence shell are called free electrons and they can move from one atom to another. This movement is called charge and the flow of electric charge is called electricity. Materials that allows many electrons to move freely are conductors and don’t allow are called insulators. That why copper is a great conductor. Alternating current would flow back and forth 50-60 times per second, this is called the frequency. Even though Thomas Edison one of the famous and powerful men of the 19th century, he tried his best to compete with Tesla. The mathematic formula of the current is P = I×V, with this formula, the same amount of power can be transmitted either at high current and low voltage or low current and high voltage. But when you transmit current through wires, there will be also loss of heat. To overcome this problem, we have to higher the voltage to reduce the heat loss.

In modern electric power grids, electricity is transmitted at hundreds of thousands of volts. But the voltage cannot be this high when it arrives at your home. So a transformer steps down this high voltage to typically between 100 and 240 volts. The step down process of AC current is way easier than the DC current. Transformers require a time varying voltage to function, and since direct current is constant, and only alternating current is time varying, transformers like these only work with AC electricity. In Edison and Tesla’s time, there was no easy way to transform voltage with direct current. And this is the primary reason Tesla’s AC won out over Edison’s DC in the early era of electrical transmission.

AC current – a scientific breakthrough

This made AC power more cost effective, as fewer power plants were needed. Entrepreneur George Westinghouse saw the potential of Tesla’s AC power and bought his patents for AC motors. Edison began a propaganda war in an attempt to keep DC power on top, but it was inevitable that ac power would win. Almost all electricity is now delivered as Tesla’s AC power. Edison’s place in history as an inventor and electrician is secure. But in many ways Tesla went even further. He envisioned fluorescent lights, technology of the radio, and remote control. Nikola Tesla was one of the most forward thinking, and dynamic visionaries that ever lived.

“If your hate could be turned into electricity, it would light up the whole world”. – Nikola Tesla

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