Gravity™ Analog Dissolved Oxygen Kit

A galvanic dissolved oxygen probe consists of a PTFE membrane, an anode bathed in an electrolyte and a cathode. Oxygen molecules defuse through the probes membrane at a constant rate (without the membrane the reaction happens too quickly). Once the oxygen molecules have crossed the membrane they are reduced at the cathode and a small voltage is produced. If no oxygen molecules are present, the probe will output 0 mV. As the oxygen increases so does the mV output from the probe. Each probe will output a different voltage in the presence of oxygen. The only thing that is constant is that 0mV = 0 Oxygen. (A galvanic dissolved oxygen probe can also be used to detect the Oxygen content in gases).

tasheet Gravity™ Analog D.O. Meter
datasheet DO sensor