The late 19th century was an exciting time for electricity and home lighting. Thomas Edison's inventions, like the lightbulb and phonograph, were taking off. But behind the scenes, a bitter rivalry was unfolding between Edison and Nikola Tesla over whose electrical system would power the world. This period became known as the "War of Currents."

Edison favored direct current (DC), which was suitable for short distances. Tesla championed alternating current (AC) that could travel farther. Their clash gave rise to tactics and propaganda that seem shocking today. Ultimately, AC prevailed and helped electrify America. But it came at a personal cost for Edison.

Edison's Direct Current System

Thomas Edison was the legendary American inventor behind the lightbulb, phonograph, and motion picture camera. In 1882, he opened the first central power plant in New York City using direct current to deliver electricity to homes and businesses.

DC flows in one direction from a power source to a device. It has some advantages:

However, DC also has limitations. The generating plants must be close to users. As current travels farther, it loses voltage through resistance in the wires. Edison's plants could only supply customers within about one mile. His Pearl Street Station in New York could illuminate about 5,000 lamps.

Tesla's Alternating Current System

In 1884, Serbian-American inventor Nikola Tesla arrived in America. He had ambitious ideas about using alternating current (AC) for electric power. With AC, the current reverses direction dozens of times per second. This allows it to travel much farther with less power loss.

The transformer, also Tesla's invention, could step up AC to high voltages for transmission along power lines. Then at substations, it could be stepped down to safer levels for consumer use. Tesla partnered with George Westinghouse to commercialize AC power.

AC current had key advantages over DC:
- Could be transmitted over long distances
- Higher voltages reduced wire costs
- Serviced more users from central plants

But AC was controversial. Many thought it was dangerous in homes due to the high voltages. Edison launched a campaign to promote DC and discredit AC power.

Edison's Propaganda Campaign Against AC

When AC first started powering cities in the late 1880s, Thomas Edison went on the offensive. He openly criticized the technology as unsafe, sparking a propaganda war against his rival George Westinghouse's AC system.

Some of Edison's tactics seem shocking today:

Edison aimed to cast doubt on AC to protect his DC power business. But Westinghouse fought back, disputing the claims through his own PR efforts. The "battle of the currents" was now an all-out media war.

AC System Prevails Due to Its Superior Economics

Despite Edison's aggressive lobbying against AC power, it ultimately prevailed due to pure economics. AC could transmit electricity over longer distances, reaching more customers for each generating plant.

Key factors that led to AC's victory:

With AC, massive projects like the Niagara Falls hydro plant became feasible. Within decades, AC networks crisscrossed the nation, bringing electricity to cities and rural communities. Westinghouse won the bid to light the 1893 Chicago World's Fair. This cemented AC as the foundation of modern electric grids.

Personal Toll on Edison and His Reputation

While AC transformed America's electrical landscape, the "War of Currents" took a personal toll on Edison. The Wizard of Menlo Park went from folk hero inventor to ruthless businessman in the public eye.

Edison remained an active inventor into the 1920s. But the brutal AC/DC current war had forever changed his reputation. Despite his many pioneering contributions, the battle highlighted a darker side of his competitive nature.


The War of Currents was one of the most impactful clashes in industrial history. AC power allowed for the widespread electrification that shapes modern civilization. But the heated rivalry also showed how far some will go to gain advantage over competitors. It transformed technology, business, and the public's perception of Thomas Edison.