Circuit for turning on motherboard

A circuit for automatically turning on and off a motherboard repeatedly in a motherboard test, the circuit comprising:

• a first switch module comprising a first transistor and a second transistor, a collector of the first transistor connected to a standby power and a sixth terminal of a computer front panel header which controls turning on and off of the motherboard, an emitter of the first transistor being grounded, a drain of the second transistor arranged to receive the standby power and connected to the base of the first transistor, a source of the second transistor being grounded;
• a second switch module comprising a third transistor and a fourth transistor, a collector of the third transistor connected to the gate of the second transistor, an emitter of the third transistor being grounded, a base of the third transistor connected to a drain of the fourth transistor and arranged to receive a standby power, a source of the fourth transistor being grounded, and a gate of the fourth transistor arranged to receive the system power;
• and
• a timing circuit comprising a diode and a capacitor, the anode of the diode connected to the system power, the cathode being grounded via a resistor and the capacitor in turn, and connected to the gate of the second transistor, so that the capacitor is capable of being charged by the system power under the control of turn-off of the third transistor, and discharged through the collector and the emitter of the third transistor to ground under the control of turn-on of the third transistor.