AMPEROMETRIC CHLORINE SENSOR

The invention relates to a system comprising a processor (320); a first electrode (344) and a second electrode (346) disposed in a fluid sample; a reference power supply (326) configured to provide a predetermined voltage at the first electrode (344) that is galvanically isolated (324) from the processor (320); a sense resistor (340) having a first side coupled to the reference power supply (326) and a second side coupled to the first electrode (344); a comparison circuit (342) having a first input coupled to the first side of the sense resistor (340) and a second input coupled to the second side of the sense resistor (340) and the first electrode (344), and configured to output one or more signals to the processor (320) indicative of the voltage drop across the sense resistor (340) and the voltage provided at the first electrode (344); and a comparison power supply (348) configured to provide electrical power to the comparison circuit (342); wherein the comparison power supply (348) is a single, unipolar power supply; the processor (320) being configured to (i) adjust the voltage provided by the reference power supply (326) based on the one or more signals indicative of the voltage provided at the first electrode (344) so that the voltage at the first electrode (344) is the predetermined voltage, and (ii) determine the concentration of chlorine in the fluid sample based on the voltage drop across the sense resistor (340) and the predetermined voltage provided to the first electrode (344).