DC Current

• Direct current flows in one direction only, a straight line which does not vary with time.
  
  

DC Sources

• AA BatteryImage by Flickr.com, courtesy of Jason Rogers
  
  DC current is produced from power sources such as batteries, power supplies and DC generators. Photovoltaic devices such as solar cells also generate DC power.
  
  

AC Current

• Alternating current flows first in one direction and then the other. Its appearance is that of sinusoidal waves, which are curvy or pulsating and have patterns that repeat.
  
  

AC Sources

• AC current is produced from sources such as power supplies and AC generators. In North America, AC is 60 hertz or cycles per second, which means it changes direction 60 times per second, and 120 volts. In Europe, it is generally 50 hertz at 220 to 240 volts.
  
  

Uses

• Most electronic devices are powered using DC current. One of the main uses of AC current is supplying power to buildings.