Low-frequency noise in ZnO varistor structures

The noise spectroscopy has been used as a diagnostic tool of surge arrester varistor structures consisting of grained ZnO. The electrical properties of measured samples have been described. In the experimental study, the applied measurement system and the results of noise measurements for the selected structures of 280 V and 440 V varistors have been presented. Noise properties are related to electrical characteristics of measured specimens. It is suggested that the proposed procedure can be applied as an effective nondestructive testing method focused on defects and structural inhomogeneity detection in tested objects.