Alternating current differs from direct current in that the current does not always travel in the same direction. Rather, the direction of the flow of electrical charge changes on a periodic basis. AC generators produce alternating currents by placing a rotating conductor, called an armature, between two magnetic poles. When the conductor cuts the magnetic flux lines created between the two magnetic poles a voltage is created. The direction the conductor crosses the magnetic flux lines affects the charge: one direction creates a positive charge, while the other will create a negative charge. Slip rings on the ends of the wires of the conductor move against brushes as the conductor rotates allowing the current to be transmitted into the AC circuit.