An apparatus is used to awake an electronic device to an active mode from a standby mode in case of change in the voltage of a power supply of the electronic device. The apparatus includes a power supply for supplying electricity, a switch connected to the power supply, a low-voltage reset unit connected to the switch, a micro-controller unit connected to the switch and a monitoring and awaking unit. The monitoring and awaking unit includes an actuator connected to the switch, a bias generator and the actuator through a comparator connected to the micro-processing unit. The control over the power supply by the switch causes change in the voltage of the actuator which cooperates with the bias generator and the comparator to generate an awaking signal to awake the micro-processing unit.