A commutator is an ELECTRICAL switch that periodically reverses the current DIRECTION in an ELECTRIC motor or electrical generator. A commutator is a common feature of DIRECT current rotating machines. By reversing the current direction in the moving coil of a motor's armature, a steady rotating force (torque) is produced. Similarly, in a generator, reversing of the coil's connection to the external circuit produces unidirectional current in the circuit. The first commutator-type direct current machine was BUILT by Hippolyte Pixii in 1832.

A commutator is an electrical switch that periodically reverses the current direction in an electric motor or electrical generator. A commutator is a common feature of direct current rotating machines. By reversing the current direction in the moving coil of a motor's armature, a steady rotating force (torque) is produced. Similarly, in a generator, reversing of the coil's connection to the external circuit produces unidirectional current in the circuit. The first commutator-type direct current machine was built by Hippolyte Pixii in 1832.