A simple control and high accuracy measurement method of open-cell four-electrode conductivity electrode.

This article focuses on a synchronous rectification direct current (DC) measurement method developed for open-cell four-electrode conductivity probes used in water quality monitoring. The method simplifies control by eliminating the need for additional timing signals and reduces hardware complexity while maintaining high accuracy, achieving relative errors within 2.5% across a conductivity range of 10 µS/cm to 200 mS/cm. Experimental validation using precision resistors, standard conductivity solutions, and field tests in groundwater-monitoring wells demonstrated the method's stability, accuracy comparable to commercial sensors, and effective temperature compensation. The proposed approach offers advantages including low cost, simple calculation, no electrolysis effects, and suitability for long-term in situ monitoring, with potential for integration into multiparameter sensing systems.