Patent attributes
A power tool is provided including an electric universal motor. A power supply interface is arranged to receive at least one of Alternating Current (AC) power from an AC power supply having a first nominal voltage higher than the operating voltage of the motor, or Direct Current (DC) power from a DC power supply having a second nominal voltage that falls approximately within the operating voltage range of the motor. The power supply interface outputs the AC power via an AC power line and the DC power via a DC power line. A motor control circuit supplies electric power from one of the AC power line or the DC power line via a common node, and reduces a supply of power from the AC power line to a level corresponding to the operating voltage of the operating voltage range of the motor.