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Structural features: The entire measurement system mainly consists of two parts: an instrument (secondary meter) and a conductivity electrode (primary meter). The electrode contacts the measured solution, and the instrument displays the conductivity value, temperature, and working status of the measured aqueous solution. Working principle: Measurement principle: In order to avoid electrode polarization, the instrument generates a highly stable sine wave signal applied to the electrode. The current flowing through the electrode is proportional to the conductivity of the measured solution. The instrument converts the current from a high impedance operational amplifier to a voltage signal, which is amplified, phase sensitive detected, and filtered by a programmable signal to obtain a potential signal reflecting the conductivity; The microprocessor alternately samples the temperature signal and conductivity signal through switch switching, and after calculation and temperature compensation, obtains the conductivity value and temperature value of the measured solution at 25℃. Temperature compensation principle: The conductivity of electrolyte solution is affected by temperature changes and requires temperature compensation. The temperature coefficient of a weak aqueous solution is 2.00%℃, and the higher the concentration, the smaller the temperature coefficient. The temperature coefficient for solutions with lower concentrations (1㎲·cm-1) is not set at 2.00%℃, but is set by the user, with a range of 0.00~9.99%.