Battle of the Currents

Alternating Current versus Direct Current

On one level, the battle between alternating current and direct current was a straightforward technical question. Direct current is the more simple and uncomplicated form of current. In it, current flows in one direction, such as in a flashlight, where it flows from the batteries to the light. In the battle of the currents, direct current was developed first and was already on the market—with stations in Manhattan and in other major cities—when alternating current appeared. In Edison's day, direct current required the construction of a power station every mile or two because direct current degraded as it was transmitted down a power line.

Alternating current is much more complex. Current moves not in one direction, but in both directions, alternating approximately 60 times every second. At the time, unlike direct current alternating current was shown to be able to travel large distances with increasing success, which would allow for the development of fewer and hence more cost-effective power stations. Two other advantages stood out for the selection of alternating current: One, it could easily be sent through narrow copper wire, unlike direct current, which at the time needed larger wire; and two, it could be “stepped up” to high velocity, which enabled large volumes to be transmitted over high tension wires and then “stepped down” to low velocity for use in individual homes and applications.

Clearly alternating current enjoyed a technical advantage over direct current. But Edison had “gotten there first” and believed that he had spent too much money developing direct current to abandon it, even at the urging of some of his fellow colleagues at Menlo Park. After 11 patent infringement lawsuits against Westinghouse failed, Edison decided to go public. Such a decision led to the battle of the currents.

The Battle is Joined

The battle, depending on one's perspective, shows public relations at its most innovative and creative, or at its most desperate. As General Electric began to witness the development and popular acceptance of alternating current, Edison and his colleagues went on the offensive with the assistance of his secretary, Samuel Insull. In particular, they claimed that alternating current was unsafe (though ironically, direct current was responsible for the death of 400 people in the great blizzard of March 1988). Indeed, they published a bright red pamphlet, titled “A Warning From the Edison Electric Light Company,” which purported to explain the dangers of alternating current. Harold Passer (1953)

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