Early measurements [39, 52, 114] on the frequency response of ZnO material ceramics were achieved using a General Radio capacitance bridge, and because of the very small size of the tested samples, the applied voltage was merely 1 V r.m.s. In the frequency range 10 10 5 Hz, the calculated relative permittivity from capacitance measurements is unexpectedly high (1000 1600) considering that the relative permittivity for ZnO is in...