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TGS4260The functional principle of the TGS4260, a potentiostatic, electrolytic type oxygen sensor, is based on a 3-electrode system.

This system consists of a working electrode (WE), a counter electrode (CE) and a reference electrode (RE). All three electrodes are equipped with an air-permeable membrane and a noble metal catalyst. They are contained in a resin housing and are in contact with the liquid electrolyte.

A potentiostat is an electronic circuit used in electrochemistry to control a voltage difference between a working electrode and a reference electrode.

An electrical current generated electrolytically between the working electrode and the counter electrode is measured as the measurement signal. At the same time, an external current source regulates the potential of the working electrode relative to the reference electrode.

If the TGS4260 oxygen sensor is placed at a location where oxygen is present, the potential of the working electrode is kept at a negative value in relation to the potential of the reference electrode. The reaction is a reduction of oxygen at the working electrode and at the same time the oxidation of water at the counter electrode.

During these electrochemical reactions, ionic conduction takes place in the electrolyte and electronic conduction occurs in the external circuit. By converting the generated electrolytic current into a voltage, this can be measured at the output. The output voltage is proportional to the oxygen concentration.

The formula for the reaction of the working electrode is: O2 + 4H+ + 4e- -> 2H2O
The formula for the reaction of the counter electrode is: 2H2O - > O2 + 4H+ + 4e-