DEVICE FOR MEASUREMENT OF ELECTRIC CONDUCTIVITY OF LIQUID Russian patent published in 2009 - IPC G01N27/06 

FIELD: physics, measurement.

SUBSTANCE: invention may be used for electric measurements in oceans and seas at depths of down to 6000 meters. Device is arranged on the basis of four-electrode conductive detector of electric conductivity and, apart from it, comprises the following components: generator, differential amplifier, source of reference voltage, source of current, analog multiplexer, unit of comparison, integrating amplifier, synchronous detector, resistors and capacitors. Generator is used for control of analog multiplexer and synchronous detector. Due to deep negative connection "outlet of comparison unit - loading resistor - capacitor - current electrodes of detector - potential electrodes of detector - differential amplifier - accurate resistor - the first inlet of comparison unit", permanent level of alternating voltage is maintained at potential electrodes of detector, and this level is determined by value of resistances of two accurate resistors, current from current source and transfer ratio of differential amplifier. Alternating current excited by comparison unit and proportional to measured electric conductivity flows through current electrodes of detector and loading resistor, inducing alternating voltage on the latter, which is detected by synchronous detector. Integrating amplifier is used to maintain working point at the outlet of comparison unit at the level of reference voltage.

EFFECT: lowering of power consumed from the source of power supply, with preservation of high accuracy of measurements.

2 dwg