Direct current power furnished electric power tool, has control circuit for gradually increasing power to electric motor by increasing ratio of operating time when electric switch is turned on, such that semiconductor switch is unset

摘要

The tool has an electric motor (2) to power the tool, and terminals (6, 7) for providing direct current (DC) power. The operation of the electric motor is controlled by an electric switch. A control circuit (8) is fixed in series with the electric switch, which includes a semiconductor switch. The control circuit is designed for gradually increasing the power to the electric motor by gradually increasing ratio of operating time when the electric switch is turned on, such that the semiconductor switch is unset.