Direct-current power supply switching device for power monitoring

The invention provides a direct-current power supply switching device for electric power monitoring. The direct-current power supply switching device comprises an NMOS tube M1, a resistor R1, a resistor R2, a silicon controlled rectifier Q1, a resistor R3, a resistor R7, a silicon controlled rectifier trigger circuit and a turn-off control circuit. The drain electrode of the NMOS tube M1 is connected with one end of the resistor R1, the other end of the resistor R1 serves as the input end of the power supply switching device, and the source electrode of the NMOS tube M1 serves as the output end of the power supply switching device. The drain electrode of the NMOS tube M1 is connected with the positive electrode of the silicon controlled rectifier Q1 through a resistor R2, and the negativeelectrode of the silicon controlled rectifier K1 is connected to the grid electrode of the NMOS tube M1 after being connected with a resistor R7 in series through a resistor R3. In the switching-on process, impact on the elec