Alternating Current vs Direct Current

Transformer: A device that changes the voltage of electricity, making it higher or lower.

Electricity: Measured in amps (how much electricity flows) and volts (the pressure of the electricity).

Analogy:

  • Amps: Like the speed of water flowing through a pipe.

  • Volts: Like the pressure of water that pushes it through the pipe.

Watts: A measure of electrical power, calculated as amps times volts.

The AC/DC Battle: Tesla Versus Edison

The question: What type of electrical current comes into your home?

Thomas Edison:

  • Was involved in many inventions in the late 1800s.

  • Created a system to supply electricity.

  • Built the first big electric power plant in New York City, opened in 1882.

  • Used direct current (DC) electricity, where electrons move in one direction in a wire.

  • Problem: DC electricity loses power over long distances (about a mile).

  • Solution: Build many small DC power plants to supply enough power for a city.

Nikola Tesla:

  • Was one of Edison's workers who tried out alternating current (AC).

  • In AC, electrons quickly switch directions back and forth in the wire.

  • Transformer: Used to make AC electricity strong and send it far without losing much power.

  • Another transformer can then lower the power for homes.

Edison vs. Tesla:

  • Tesla’s AC electricity was more efficient.

  • Edison thought DC power was safer because it stayed at low, safe levels.

  • Tesla left Edison's company to work with George Westinghouse, Edison's competitor.

  • With Westinghouse's help, Tesla developed an AC power system.

  • Advantages of AC: A large power plant could be built far from a city; devices could use different amounts of power using transformers.

  • Edison's DC system needed everything to use the same low level of electricity.

Outcome:

  • Edison’s DC plants were replaced by Tesla’s AC power system.

  • Today, AC electricity powers homes and businesses all over the world.