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１０. DETECTION PRINCIPLE
The GD-F3A-1 employs a galvanic cell as oxygen detection sensor that consists of noble
metal and base metal electrodes in an electrolyte.
A membrane covers the cell and allows gas in the sampled gas to diffuse into the
electrolyte at a rate proportional to the partial pressure of oxygen. The oxygen reacts in the
cell and produces a current proportional to the oxygen content. The current develops a
voltage across a temperature compensation thermister/resistor network. The voltage is
measured by the indicator/alarm unitʼ s circuitry, converted to an oxygen gas
concentration.
Output
Electrolyte
Container
Thin electrolyte
layer
Membrane
Test gas
Counter-electrode
Working electrode
