Page 2 - LN

changes. Such a current, which changes direction after equal intervals of time, is called
an alternating current (abbreviated as AC). This device is called an AC generator.
c. To get a direct current (DC, which does not change its direction with time), a split-ring
type commutator must be used. With this arrangement, one brush is at all times in
contact with the arm moving up in the field, while the other is in contact with the arm
moving down. Thus a unidirectional current is produced. The generator is thus called a
DC generator.