An electronic device includes an optical module, a power source module powering the optical module, a processor, a controller, and a switch module. The processor generates and maintains a delay signal for a first predetermined time in response to determination that the power source module is powered on. The processor further generates a driving signal upon determination that the first predetermined time has elapsed. The controller generates and maintains a control signal for a second predetermined time in response to determination that the power source module is powered on. The switch module is turned on to establish an electrical connection between the power source module and the optical module according to the driving signal, and turned off to cut off the electrical connection according to the control signal.