AC/DC, Edison, and Tesla- an Introduction to Modern Electric Current

Direct Current vs. Alternating Current

• Direct current (DC) is the unidirectional flow of electric charge.

• Direct current is produced by sources such as batteries, solar cells, and other electric machines

• Direct current may flow in a conductor such as a wire, but can also flow through semiconductors, insulators, or even through a vacuum

Direct Current vs. Alternating Current• In the alternating

current distribution system power could be transmitted more efficiently over long distances at high voltages, around ten times that of the loads, using lower current. • With AC current, a transformer is used to down step

the high voltage to low voltages for use in homes and factories. This has the practical significance that fewer, larger generating plants can serve the load in a given area.

Thomas Edison- Inventor or Salesman?• During the initial years of

electricity distribution, Edison's direct current was the standard for the United States, and Edison did not want to lose all his patent royalties.

• The Direct Current system required a power plant every square mile and couldn’t transmit electricity very far- which meant more money for Edison

Meet Nikola Tesla• Nikola Tesla was a Serbian

American inventor, electrical engineer, mechanical engineer, physicist, and futurist best known for his contributions to the design of the modern alternating current electricity supply system

• He was one of the greatest inventors to have ever lived- but, he was totally crazy. And because of this, often wasn’t given credit for many of his inventions

• Tesla came to the USA to work for Edison, who had control over most big inventions and patents being created at the time.

• Edison, intimidated by Tesla’s idea for the AC system and his general intelligence, fired Tesla.

War of Currents- who won?

• The International Electro-Technical Exhibition of 1891 featured the long distance transmission of high-power, three-phase electric alternating current.

• By this time, everyone agreed that AC current was the more efficient and adaptable, despite Edison’s efforts

• In Europe, the three-phase system of 60 Hz at 120 volts became the dominant system in North America because it was still thought to be safer, while 220-240 volts at 50 Hz became the standard in Europe.

• While DC current did not prevail, Edison still owned patents to most advances in electricity at this point

International Electro-Technical Exhibition

• By the end of his life, Tesla arguably invented or came up with the plans for: radar, x-rays, hydroelectric power, the transistor, the remote control, the modern electric motor, and wireless communication, but because he was generally thought to be insane, he wasn’t credited with any of these inventions.

• Tesla died broke and alone in a hotel room in NYC. He never married or even had a girlfriend, although at the end of his life was finally able to connect with another being…