An electronic device includes a signal generator and a processing module. The signal generator generates reset signals to reset the processing module. The signal generator includes a first capacitor, a second capacitor, and a switching unit. The first capacitor receives an input voltage and charges accordingly when the electronic device is powered on. The second capacitor generates the reset signals based on the input voltage. The switching unit transmits the input voltage to the second capacitor to charge the second capacitor when the electronic device is powered on, and grounds the second capacitor after the electronic device is powered off. The reset signals are generated during the charging and discharging process of the second capacitor.