A power tool configured to receive power from a power supply, the power tool comprising: an electric motor; a rectifier configured to receive an alternating current from an alternating current power supply and output a rectified signal supplied to a DC power bus; a switching arrangement having a plurality of motor switches connected electrically between the DC power bus and the electric motor, and operates to deliver electric power from the DC power bus to the electric motor; a switch path electrically coupled in parallel with the rectifier on the DC power bus, wherein the switch path includes an auxiliary capacitor in series with a switch and state of the switch controls a discharging path for the auxiliary capacitor; and a switch control circuit configured to detect voltage associated with at least one of the AC power supply or the DC power bus and to control state of the switch in accordance with magnitude of the detected voltage; wherein the switch control circuit includes a sensing circuit and a comparator, the sensing circuit is configured to detect the voltage across the DC power bus, and the comparator is configured to compare the voltage detected with a predetermined threshold and outputs a signal to the switch to control the state of the switch; characterized in that the sensing circuit includes a voltage divider (R323, R333, R334) that is electrically coupled to the DC power bus and the comparator, and the comparator includes a transistor and a diode, the diode is coupled between the DC power bus and the emitter of the transistor, the base of the transistor is coupled to the voltage divider (R323, R333, R334), and the collector of the transistor is coupled to the switch to control the state of the switch. an electric motor; a rectifier configured to receive an alternating current from an alternating current power supply and output a rectified signal supplied to a DC power bus; a switching arrangement having a plurality of motor switches connected electrically between the DC power bus and the electric motor, and operates to deliver electric power from the DC power bus to the electric motor; a switch path electrically coupled in parallel with the rectifier on the DC power bus, wherein the switch path includes an auxiliary capacitor in series with a switch and state of the switch controls a discharging path for the auxiliary capacitor; and a switch control circuit configured to detect voltage associated with at least one of the AC power supply or the DC power bus and to control state of the switch in accordance with magnitude of the detected voltage; wherein the switch control circuit includes a sensing circuit and a comparator, the sensing circuit is configured to detect the voltage across the DC power bus, and the comparator is configured to compare the voltage detected with a predetermined threshold and outputs a signal to the switch to control the state of the switch; characterized in that the sensing circuit includes a voltage divider (R323, R333, R334) that is electrically coupled to the DC power bus and the comparator, and the comparator includes a transistor and a diode, the diode is coupled between the DC power bus and the emitter of the transistor, the base of the transistor is coupled to the voltage divider (R323, R333, R334), and the collector of the transistor is coupled to the switch to control the state of the switch.