DEGRADATION PHENOMENA DUE TO IMPULSE-CURRENT IN ZINC-OXIDE VARISTORS

Abstract

The relationship between the electrical characteristics of the ZnO varistors and applied current impulse is investigated in this study, The degradation phenomena of the ZnO varistors due to current impulse are studied by I-V and ac measurements, The influence of various numbers of applied surge on the I-V behaviors, V-0.1mA and leakage current, is attributed to the asymmetrical deformation of the grain-boundary barriers, As the applied impulses increase, the changes observed in the properties of deep bulk trap and conduction mechanism are attributed to the alternation of defect structure and model of conduction.