Since the voltage coefficient of the measured capacitor is very small, socan consider its voltage coefficient value is 0 when the voltage of the capacitor is very low. Therefore, the paper chooses 30 V to be the point of 0 voltage coefficient value after considering the characteristics of the capacitors and bridge. And use the capacitance value of 30 V to be the reference value to measurement and calculate the other values when the voltage of the capacitor in different. The measuring process is follow (T=20°C, RH=44%):