A switching method, including: electrically coupling a switching circuit to a first impedance circuit, a second impedance circuit, a positive terminal of a frequency generation circuit and a negative terminal of the frequency generation circuit; adjusting an impedance value of the second impedance circuit according to a first clock signal and a second clock signal outputted by the frequency generation circuit; periodically conducting the negative terminal to one of the first impedance circuit and the second impedance circuit by a first switching unit of the switching circuit; and periodically conducting the positive terminal to the other one of the first impedance circuit and the second impedance circuit by a second switching unit of the switching circuit.