An electronic device includes an audio power amplifier used to output a left and a right channel audio signal, an earphone jack assembly, and a switching circuit automatically switching between a speaker mode and an earphone mode. The audio power amplifier includes a control pin enabling the audio power amplifier to be electrically connected to the speaker. The control pin activated at a low level and disabled at a high level. The switching circuit is capable of enabling the control pin to switch between the low level and the high level. The switching circuit includes a power supply, a first resistor, a second resistor, a third resistor, and a diode. The resistance of the third resistor far exceeds that of the first resistor.