Title: Capacitive humidity transducer

Abstract: A capacitive humidity transducer wherein an electrically non-conductive base carries at least a pair of electrically conductive coatings which are spaced from each other. A dielectric film which is active with respect to water absorption is also carried by the base and covers at least portions of the coatings, the dielectric film having a dielectric constant the value of which varies as a function of the extent to which water has been absorbed by the dielectric film. An outer electrically conductive, water-permeable layer is carried by the dielectric film with this film being situated at least in part between the coatings and the layer while the latter because of its water permeability permits moisture in the atmosphere to reach the dielectric film. The dielectric film maintains the outer layer permanently out of contact with at least one of the coatings, so that it is possible to measure between these coatings a capacitance which will be indicative of atmospheric humidity.

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Inventors: Suntola, Tuomo S. (Espoo, FI)

Application Number: 598034
Filing Date: 1975-07-22
Publication_date: 1979-08-21
Assignee: Vaisala Oy (FI)
Primary Class(es): 73/335.04 361/286
Other Classes:
US Patent Ref:

3247478	Apr, 1966	Craig	73/336.
3257587	Jun, 1966	Krafft	317/246.
3315518	Apr, 1967	Charlson et al.	73/336.
3328653	Jun, 1967	Wol, Jr.	317/246.
3350941	Nov, 1967	Misevich et al.	317/246.
3550439	Dec, 1960	Hollies et al.	73/336.
3559456	Feb, 1971	Lomker et al.	73/336.
3582728	Jun, 1971	Thoma	73/336.
3671913	Jun, 1972	Mamiya	73/336.
3735023	May, 1973	Hurst et al.	29/592.
3802268	Apr, 1974	Thoma	361/286.

Other Refs:
Primary Examiner: Yasich, Daniel M.
Assistant Examiner:
Attorney: Steinberg & Blake