Accuracy improvement of resonant sensor by an additional electrode in the measurement of liquid density and viscosity

Purpose In the measurement of liquid density and viscosity, the change of resonance parameters due to the parasitic parallel capacitance of resonator affects the measurement accuracy. To improve the accuracy, a method was proposed to compensate the parasitic parallel capacitance of resonator by adding an electrode. Design/methodology/approach The new electrode (compensation electrode) was added into resonant sensor to make compensation capacitance. The closer the compensation capacitance was to the parasitic parallel capacitance, the better compensation was. The structural parameters of resonant sensor with the compensation electrode were determined by the simulation and experiment. Findings The effect of this method was examined by the experiment. The relative errors of density and viscosity were less than 0.15, 0.5 % and standard deviations were less than 0.0004 g/cm 3 and 0.005 mPas, respectively. Practical implications The experimental results show that this method is valuable for the parasitic parallel capacitance compensation of immersed resonant sensor. Originality/value This paper has not been published in other journals.