CK-12 Physical Science Concepts - For Middle School

(Marvins-Underground-K-12) #1

5.66. Direct and Alternating Current http://www.ck12.org


Alternating Current


When current keeps reversing direction, it is calledalternating current (AC). You can see how it works in the two
diagrams below. The current that comes from a power plant and supplies electricity to homes and businesses is
alternating current. The current changes direction 60 times per second. It happens so quickly that the light bulb
doesn’t have a chance to stop glowing when the reversals occur.


Q:Which type of current flows through the wires in your home?


A:Alternating current from a power plant flows through the wires in a home.


Summary



  • Direct current (DC) keeps flowing in just one direction. Batteries provide direct current.

  • Alternating current (AC) keeps reversing direction. Power plants provide alternating current.


Vocabulary



  • alternating current (AC): Electric current that keeps reversing the direction in which the current flows.

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