The RKFT/A duct humidity and temperature sensor with transducer measures the relative humidity 0...100% r.H. and the temperature of the ambient air by a capacitive sensor and transforms it to a linear output signal 0-10 V or 4-20 mA. The humidity and temperature sensor is protected against contamination by a screwable sinter filter. The humidity and temperature transducer can be adjusted locally for fine calibration by an offset controller.