MiCS Compact MOS Sensors - Amphenol SGX Sensortech | Mouser Amphenol SGX Sensortech MiCS Compact MOS Sensors and their associated tools work on the principle that the resistance of the sensor's detecting layer changes in the presence of the target gases. The resistance will increase for oxidizing gases such as ozone or nitrogen- dioxide and for reducing gases such as carbon monoxide or volatile organic compounds, the resistance will go down.