At chemosorption the sensor element is integrated in a diplexer. The sensor element has the characteristic to change its electrical resistance depending on the surrounding gas concentrations.

The semiconductor is heated up tp 300°C. During absorption of the combustible and sometimes toxic gases on the sensor surface, the resistance of the sensors are reduced. This resistance change is evaluated electrically.

Different semiconductors are used for different gases. Chemosorption sensors are used for combustible and toxic gases. As sensor element for eg.zinnasche (SnO2) sintered N-substrate is used.