Using FFT analysis as shown in Fig. 8 and Fig. 9, it is hard to identify a difference between normal and faulty cases, al-though a change in the primary capacitor is increased the peak by 21 % but there is no difference in the phase shift. The reso-nant frequency of fingerprint case output voltage and input current is around 1000 Hz. Once more, via the transfer func-tion in the frequency, more remarked differences are observed, as shown in Fig. 10. Table III summarizes the consequences of the transfer function in time and frequency domains, where Am is the peak amplitude of the resonant pole. It is noted fm, frequency of the resonant pole, is 1000 Hz for all cases.