We present a novel low-cost experimental method for measuring the electrical conductivity and relative permittivity of liquids at low frequencies. Based on the different relationship between the resistive and capacitive currents with an applied voltage, the resistance and capacitance of fluid test cell can be obtained independently from different time regions of a triangular waveform voltage (TWV). The electrical conductivity and relative permittivity of test liquids can be derived following calibration of the cell constant. This novel technique avoids measuring current-voltage phase shift angles that are sometimes exceedingly small, requiring high-precision instrumentation. The new method also eliminates the need for interpretation of the cell in terms of an equivalent circuit to obtain the cell resistance and capacitance from the measured cell impedance. It can be seen from numerical demonstration of a real TWV that the measured cell resistance and capacitance by the TWV technique is merely determined by the liquid under test and insensitive to the waveform of the applied TWV. The TWV technique is validated by measuring sample liquids at low frequencies, whose properties are well known. © 2005 IOP Publishing Ltd.
CITATION STYLE
Wu, J., & Stark, J. P. W. (2005). A low-cost approach for measuring electrical conductivity and relative permittivity of liquids by triangular waveform voltage at low frequencies. Measurement Science and Technology, 16(5), 1234–1240. https://doi.org/10.1088/0957-0233/16/5/025
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