An electronic device includes a capacitance electro-acoustic transducer and an audio driver. The audio driver is coupled to the capacitance electro-acoustic transducer. The audio driver includes a high-voltage amplifier for receiving an input audio signal and for transforming the input audio signal into an output audio signal to drive the capacitance electro-acoustic transducer, wherein an absolute voltage value of the input audio signal is smaller than an absolute voltage value of the output audio signal. The output bandwidth of the capacitance electro-acoustic transducer is controlled by the magnitude of the output current of the audio driver. The capacitance electro-acoustic transducer of the present invention can meet different bandwidth requirements and thus achieve saving power, which cannot be achieved by a traditional dynamic electro-acoustic transducer.