| 摘要 |
The invention relates to gas sensors, particularly electrochemical gas sensors. Reliability of gas sensors has been ascertained by regular tests which involve exposing a sensor to a gas for test or calibration purposes. However, it has been difficult to provide a known quantity or concentration of gas. Another problem has been that blockage of a gas inlet has rendered the gas sensor unreliable. The invention provides a gas sensor having a self test capability and first and second electrodes, arranged so that test gas arrives at a separate instant at each electrode so as to generate two electric currents, the ratio of which currents provides an indication of the status of at least one electrode.
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