PURPOSE: To increase the accuracy by detecting the pressure by measuring the variation of the static capacitance of the titled varistor at a relatively low frequency in a specific range.
CONSTITUTION: Metallic oxide such as bithmus oxide, cobalt oxide and antimony oxide are added to zinc oxide, and the varistor calcined at a high temperature is heat-treated so as to contain bithmus oxide of centroid cubic system, thus electrodes on both surfaces. The relation between the pressure of this varistor and the static capacitance, is the variation of the static capacitance is large at a frequency of 50∼120Hz, and the temperature dependence thereof is small. Therefore, measurement of the variation of said capacitance at a fixed frequency, using such a zinc oxide varistor, enables to pressure of a high accuracy.
MORITA TOMOJI
SATOU KEN
