AC/DC The Current Hits
Electricity is produced through the induction of electric current. By moving a wire across the lines of a magnetic field, or moving the magnetic field across the wire, one can produce electricity.
The direction of the current may be constant or may change direction. • If the wire or magnet is moved in only one direction the current will flow in that direction. If you reverse the direction you will reverse the flow.
Direct Current DC • A current which consists of charges that flow only in one direction only is called Direct Current. • A battery produces direct current. • Electrons move away from one end of the battery, around the circuit, and into the other end of the battery.
Alternating Current AC • If a wire in a magnetic field were moved up and down repeatedly, the current in the wire would also reverse direction repeatedly. • A current consisting of charges that move back and forth in a circuit is an alternating current. • The electric current in your home is alternating current.
Generators • An electric generator converts mechanical energy into electrical energy. • An electric generator is the opposite of an electric motor. • An electric motor uses an electric current to produce motion. • A generator uses motion to produce an electric current.
AC Generator Inside the generator, a loop of wire is moved up and down inside of the magnetic field and every half turn, the wire changes direction within the field. The result is a change of direction in the current of the wire.
DC Generator A DC generator is the same as a DC motor. As a matter of fact, if you run electricity through a DC motor, it will spin and the spinning will produce electric current.
Edison’s contribution • Because of the simplicity of Direct Current Generators producing electricity, T.A. Edison decided to use DC as the source of current for his electric company. • One by-product of DC is heat.This made DC electricity a potential cause of house fires. • Because much of the energy was lost through heat, DC couldn’t be sent over long distances, so there would be a need for more generators closer together.
Tesla’s contribution • N. Tesla was able to produce Alternating Current, using fewer generators. • There was much less energy loss through heat, making AC safer and more efficient. • AC could be sent over longer distances than DC. • All of these reasons led to the wide use of AC in homes.
Bibliography Thomas A. Edison, 1878. Photo courtesy of U. S. Department of Interior, National Park Service, Edison National Historic Site. Found at : http://memory.loc.gov/ammem/edhtml/edsndimg.html Thunderstruck by AC/DC 1992 Leidseplein Presse B.V. Atco Records, Division of Atlantic Recording Corp., 75 Rockefeller Plaza, New York, New York 10019 TESLA, NIKOLA. Wood engraving. Photographed by Sarony; engraved by T. Johnson. [1906? Location: Century Magazine, v. 47, p. 585 (reference copy in Biographical File) Reproduction Number: LC-USZ62-61761 Found at: http://lcweb.loc.gov/rr/print/235_pot.html#TeslaN