Most household appliances utilize DC power. So why do we generate AC at power stations?

Let’s go back to the war of the currents in the late 19th century. Edison championed his Direct Current system and Tesla had invented the Alternating Current system which was manufactured and run by Westinghouse.

The first US worlds fair, called the Columbian Exhibition was to be held in Chicago. Edison and Westinghouse bid on lighting the fair. This would be the first time many people would see electric lights. Westinghouse’s bid was half that of Edison’s.

The reason Edison lost is that wires have resistance. The power lost over the transmission wires is calculated by Pdiss = (I^2)*R. So if you lower the current the the losses drop by the square of the current, which is quite significant. Tesla’s secret weapon was the transformer.

At the sending end, he would boost the voltage, which reduces current by the formula I = P/V. It is then sent the distance with lower loses. At the receiving end Tesla stepped the voltage down returning the current back to its original level.

Edison could not do this because a transformer needs an alternating magnetic field to induce a current in its secondary. This is the point at which the world embraced Tesla’s system over Edison.

Edison had run a smear campaign against A.C. power. He electrocuted animals to “prove the dangers” of A.C. power. In the process, Edison invented the electric chair. In the lomg run, it came down to simple economics.

Since we have A.C. coming into our houses, motorized appliances use A.C. motors. It is electronics that must convert the A.C. to D.C.

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