Beginning his research in 1962, Mr. Naoyoshi Taguchi became the first person in the world to develop a semiconductor device that could detect low concentrations of combustible and reducing gases when used with a simple electrical circuit.
The electrodes are typically fabricated by fixing a high surface area of precious metal onto the porous hydrophobic membrane.
The gas diffuses into the sensor, through the back of the porous membrane to the working electrode, where it is oxidized or reduced.
In addition to measuring, amplifying, and performing other signal processing functions, the external circuit maintains the voltage across the sensor between the working and counter electrodes for a two-electrode sensor or between the working and reference electrodes for a three-electrode cell.
A linear output allows for more precise measurement of low concentrations and much simpler calibration (only a baseline and one point are needed).