氧化锌压敏电阻8/20 μS脉冲电流下的伏安特性曲线分析

Analyses of Zinc Oxide Varistor's Response Characteristic V/I-curve to 8/20 μS Surge Current

氧化锌压敏电阻器在8/20μS脉冲电流下的伏安特性曲线,在电流上升沿和和下降沿呈现不重合的回线特征。本文以压敏陶瓷体在击穿后的电流区以非线性电阻、晶粒电阻、等效电感和引出电阻相串联的物理模型为基础,提出陶瓷体等效电感、电极等效电感和引线电感共同构成压敏电阻的等效串联电感,电极等效电阻和引线等效电阻共同构成引出电阻,串联电感形成回线特征。按照这一模型,用测量数据可以推算出不同电流点的串联电感值,等效电感值是一个常数,并可推断陶瓷体等效电感确实存在且为常数。可以确认,除了引出电感(含引线电感和电极等效电感)外,伏安特性的回线特征是压敏陶瓷体的本征特性。

The Volt-ampere Characteristic Curve of ZnO Varistors under 8/20 μ S impulse current shows that its rising processdoes not repeat its falling process. The article, based on the physical model series-wound by non-linear resistance, grain resistance, equivalent inductance and leading-out resistance, a current area following the breakdown of pressure-sensitive ceramic body, advances that ceramic equivalent inductance, polar equivalent inductance, and lead inductance comprise equivalent series-wound inductance of pressure-senstive resistance, polar equivalent resistance and lead equivalent resistance comprise lead-out resistance, series-wound inductance comprises loop wire characteristics. Based on the model, series-wound inductance values of different current spots can be measured, equivalent inducance value is invariable, and it also can be concludes that ceramic equivalent inductance can be invariable. It can be sure that besides lead-out inductance（including leading wire inductance and polar equivalent inductance, the loop wire Characteristics of volt-ampere characteristics are intrinsic features of pressure- sensitive ceramic body.