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 and an inner electrode, and between the outer electrode and the inner electrode, applies square wave AC voltage having an amplitude of 1 V to 42 V and a frequency of 0.5 Hz to 30 Hz.

主权项

1. A resistivity-measuring circuit that measures resistivity in order to sense deterioration of a liquid sample, the resistivity-measuring circuit
being one that measures the resistivity of the liquid sample between a pair of electrodes by detecting voltage generated between the pair of electrodes, having a shield drive circuit using an operational amplifier, the shield drive circuit zeroing a potential difference of floating capacitance formed between wiring lines respectively connected to the pair of electrodes, and between the pair of electrodes, applying square wave AC voltage having an amplitude of 1 V to 42 V and a frequency of 0.5 Hz to 30 Hz.