Dynamic measurement method for distributed capacitance of electrode concerned in measurement of conductivity of solution

Abstract

The invention discloses a dynamic measurement method for the distributed capacitance of an electrode concerned in the measurement of the conductivity of a solution. A signal of an alternating-current symmetrical triangular wave with the voltage amplitude of U and a fixed period is adopted to excite an electrode, the wave trough (or the wave peak) of the triangular wave is used as an origination moment, the 3 time quartering division point moments of the upper wave band (or the lower wave band) of the triangular wave are respectively used as destination moments for integrating the response current of the electrode, the three current integral values are respectively set as q1, q2 and q3, and the distributed capacitance Cp of the electrode of a conductance cell, needing to be measured, is obtained by utilizing the following formula. The dynamic measurement on the distributed capacitance of the electrode of the conductance cell can be used for laying a foundation for the precise measurement on the conductivity of the solution, which is influenced by the distributed capacitance of a quantified electrode.

Description

technical field [0001] The invention relates to a dynamic measuring method of electrode distributed capacitance of a conductance cell, in particular to a dynamic measuring method of electrode distributed capacitance of a conductance cell using a triangular wave as an excitation signal. Background technique [0002] The basic measurement method of solution conductivity is to measure the voltage U applied across the electrodes placed in the solution. D and the current I flowing through the electrodes, calculate the resistance R=U between the electrodes D / I, use G=K / R to calculate the conductivity of the solution, where K is the electrode constant. However, the electrode placed in the solution will be polarized after being energized, so that the measured voltage U D In essence, it is not the voltage across the solution itself, but the voltage applied to the two virtual electronic devices in series, the solution resistance and the electric double layer capacitance involving t...

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Problems solved by technology

There will be some errors in the electrode distributed capacitance Cp measured by this method, the main reason is that when the conductivity of the solution is tested, the solution between the electrodes of the conductivity cell is filled with the solution to be measured, and the solution filled between the electrodes of the conductivity cell is equivalent to that of the electrodes. A medium between the plates, the dielectric constant of the measured solution as a medium will be different from that of air, so the electrode distribution capacitance measured by placing the electrode in the air is the same as the electrode distribution measured by placing the electrode in the measured solution Capacitance will vary

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