This model represents a electric toothbrush that uses electric power supplied by two rechargeable NiMH batteries. When the switch is in the "off" position, the circuit is open and there is no voltage across the DC motor. When the switch is turned on, the current flows into the DC motor, causing the motor shaft and the spur gear attached to the motor shaft to rotate. The spur gear meshes with the ring gear which is provided with an eccentric crank pin. As the crank pin rotates, it pushes the connecting arm and causes brushhead to osillate rapidly through the slider-crank mechanism.