
The structure of the sensing element is demontrated in Fig. 2.4.
There is a thin gold layer, a hygroscopic polymer layer, a electrode system and a
ceramic substrate.
Figure 2.4: Sensing Element
[Physics of the Humidity Technology,
R. Freitag, PowerPoint Presentation, 4/07]
The Polymer is to be poised with the environment and store water, where the thin
goldlayer is water vapour permeable. By this means a storage of the H
2
O-dipol
causes a change of the dielectric within the capacitor which depends on frequency.
So capacity increases by availability of charge carriers which is detected within the
connected electronics for further converting processes.
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