Direct-Reading Method for Nonlinearity Index of Silicon Carbide Varistor

This paper presents a direct-reading method for the nonlinearity index of silicon carbide varistor. Varistors of voltage rated from 50 V to 700 V can be measured without range switching. Measurement is made either at 0.1 and 1 mA or 1 and 10 mA of the varistor current. Precalibration is made by using an ordinary resistor. Measurement accuracy is -3 percent.