Patent ID: 8324913

Claim:
A moisture sensor comprising: a receiving area retaining a moisture film, wherein a thickness of said moisture film is a function of relative humidity surrounding the receiving area; a signal source configured to generate a control voltage, wherein the signal source provides a control voltage to the moisture film and is connected to at least one control electrode having at least one infeed connected to the moisture film, the control electrode abutting the receiving area; at least one potential sensor, having at least one sensor area positioned under the receiving area, said potential sensor being spaced apart from the at least one infeed and being electrically insulated by an insulation layer located between said sensor area and said receiving area, whereby said potential sensor capacitively detects an electric potential which is a function of the layer thickness of the moisture film and the control voltage; an evaluator connected to the measurement signal output of the potential sensor, wherein (a) the signal source is configured to generate a variable control voltage and the evaluator is configured to generate a signal dependent on the rate at which the potential sensor measurement signal changes in response to the change of the control signal and/or (b) the evaluator is configured to generate a signal for a potential shift between the measurement signal of the potential sensor and a reference signal or a reference potential.