The Impact of Oxygen on MIS Hydrogen Sensing

The metal–insulator–semiconductor (MIS) sensor responds to both hydrogen and oxygen. The animation below shows how the calibration curve relating hydrogen to voltage looks at different oxygen concentrations. Observe that the calibration curve is much less sensitive, (moves more slowly), at high oxygen (>2000 PPM) than at low oxygen. At high oxygen, the MIS sensor is effectively a single gas sensor.

O2 Dissolved in Oil H2 Dissolved in Oil Versus Measured Voltage