Abstract: A method for determining the absolute humidity of air by aid of a capacitive sensor and a temperature sensor as well as a heating element. The sensor temperature is changed upon reaching a predetermined humidity limit value. In order to eliminate the risk of falsified measuring values and to enable long-time stable and accurate measuring also in the high-humidity range, the determination of the humidity of air until reaching the predetermined humidity limit value is effected by evaluating the value measured for the capacity of the sensor. Upon reaching a predetermined limit value, the temperature of the sensor is controlled to a constant sensor capacity by heating and is evaluated.

Abstract: A process is disclosed for producing a swellable plastic resistive moisture sensor comprising dispersing an additive selected from the group consisting of carbon in powder, dust or soot form, carbon black, graphite, a metal in powder or dust form, and mixtures thereof, into a plastic comprising a polyimide or a copolyimide or both formed from diisocyanate and dianhydride reactants.