The characterization of insulating materials using triangular signals of very high period

A triangular symmetric signal of very high period is employed for the measurement of electrical properties at very low frequency. The response of an insulating material to such a signal is analyzed to determine dielectric properties including the complex permittivity, relaxation frequency and the dynamic resistance. The obtained values for dielectric permittivity are in good agreement with the values obtained in ac measurements. The dynamic resistance of the sample is small compared with the dc value. The passing from one polarization mechanism to another appears as a change in the slope of the measured current and so the charge responsible for a particular mechanism can be determined. The accumulation of space charge inside the sample is indicated by distortion of the signal. From the shape of the current at low fields it is concluded that the metal-dielectric contact is ohmic.