A Primer on AC/DC

In the late 1880s, a war was quietly brewing—a battle of three of the world’s greatest minds that would change the world and the way we lived.

Through late into 1887, direct current was the only way to go when it came to electrical power. Thomas Edison, the inventor of DC, established 121 power generators in strategic areas of the U.S. to service customers as an alternative to candle or gaslight. But his product had one major drawback: DC was weak and couldn’t be transmitted very far before it began to fail.

That same year, Nikola Tesla filed several U.S. patents for a system of products—lights, generators, transmission equipment and the like. The plans were so revolutionary that George Westinghouse instantly believed they might be what he needed to finish his work on electrical power that could be transmitted longer distances. For $60,000 (more than $1.6 million today) and shares in Westinghouse stock, he purchased some of Tesla’s patents.

It turned out to be exactly what Westinghouse needed to perfect his alternating current, a system in which the electrical charge changes direction periodically, as opposed to direct current, which only moves in one direction.

But when Westinghouse debuted his invention, Edison grew quite unhappy with the new upstart. Afraid of losing money and a place in the market, Edison began to sow seeds of discontent by falsely claiming that AC was dangerous. In an effort to “prove” his claims, he executed a few stray dogs and cats with the newfangled electricity.

Despite Edison’s fight, Tesla and Westinghouse were making great inroads on their alternating current. In 1893, Westinghouse Corp. won the bid for the right to illuminate the Chicago World’s Fair.

Today, more than 75 percent of our electrical devices utilize AC power. Yet, Edison’s DC—though not as strong as AC—is still valuable, used today to power cell phones, solar lights, laptops, car batteries and flashlights.