RESISTIVITY-MEASURING CIRCUIT, CELL FOR MEASURING LIQUID SAMPLE, RESISTIVITY-MEASURING APPARATUS, LIQUID SAMPLE CONTROL METHOD AND LIQUID SAMPLE CONTROL SYSTEM

摘要

The present invention is one that makes it possible to continuously measure the resistivity of a liquid sample with accuracy as well as preventing the deterioration of the liquid sample associated with measurement, such as change in quality, and relates to a resistivity-measuring circuit C that measures the resistivity in order to sense the deterioration of the liquid sample. The resistivity-measuring circuit C is one that calculates the resistivity of the liquid sample by detecting voltage generated between an outer electrode 21 and an inner electrode 22, and between the outer electrode 21 and the inner electrode 22, applies square wave AC voltage having an amplitude of 1 V to 42 V and a frequency of 0.5 Hz to 30 Hz.