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Electronics Basics: The History of AC/DC Current Wars

Alternating current (AC) isn’t only used in electronic devices, it is the worldwide standard for power distribution. This wasn’t always the case, however. Back in the days when electricity was first being put to practical use, direct current was the normal way to distribute electricity.

The biggest champion of direct current was none other than Thomas Edison himself, the Great American Inventor who is credited with inventing just about everything from the light bulb to the phonograph to the motion picture.

In 1880, Edison patented a system of electrical power distribution based on direct current and opened the first public electric utility company in 1882, providing electricity to 59 customers in New York. By 1890, he had more than 100 power plants operating nationwide.

Thomas Edison’s biggest rival was a fellow named George Westinghouse, who advocated the use of alternating current for power distribution and promoted a system developed by the brilliant but eccentric inventor Nicola Tesla.

Westinghouse promoted the benefits of alternating current over direct current — primarily the benefit that alternating current could transmit power efficiently over much larger distances than direct current. Edison’s direct current system required that power plants be located within a few miles of customers. But Tesla’s alternating current system could deliver power hundreds of miles away from the power plants.

Edison responded to the negative publicity of direct current the way any true-blooded American marketer would: by launching a smear campaign. In 1887, a man was accidentally killed when he touched bare power lines. Edison had one of his employees develop a method of intentionally killing people with electricity. Hence, the electric chair was invented.

Of course, the electric chair used alternating current to electrocute its victims. Edison launched a nationwide publicity campaign to convince the public that alternating current was so dangerous that it was used in prisons to kill condemned murderers. He even went so far as to conduct public executions of stray dogs and, in one case, an elephant. The message was clear: You don’t want this dangerous stuff in your house.

Fortunately, the smear campaign didn’t work. The benefits of alternating current eventually won out. The turning point came when the alternating current generators at Niagara Falls began operating in 1896, delivering power 20 miles away to Buffalo, NY. By the early part of the twentieth century, nearly all power distribution worldwide was done with alternating current.

Direct current distribution lasted much longer than you might think, however. Con Edison — one of the largest electric companies in the world and the direct descendant of Edison’s original electric company — did not convert its last few holdout customers over to alternating current until 2007.

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