The sensors FK80J (humidity only) / TFK80J (humidity and temperature) measure the air humidity by means of a humidiy-dependant condenser. The capacitive humidity measuring element, produced using thinfilm technology, consists of a base plate, on which the
electrodes are housed and a hygroscopic polymer layer avove it.
The hygroscopic polymer layer absorbs water molecules from the medium to be measured (air) or releases them, thereby altering the capacity of
the condenser. In a tandem-arranged electronic device, the change in capacity is processed via integrated signal preprocessing into signals 0..20mA or 0..10VDC or 4..20mA.