Capacitive moisture sensor
First Claim
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1. A capacitive moisture sensor comprising:
- an insulator;
a sensing capacitor having spaced capacitive sensor conductors mounted with said insulator for exposure to the atmosphere;
first and second electrodes mounted with said insulator remote from said spaced capacitive sensor conductors; and
circuitry connected to apply a current to said first and second electrodes and to detect a change in capacitance between said first and second electrodes indicative of moisture bridging two of said capacitive sensor conductors.
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Abstract
A capacitive moisture sensor includes insulator means; capacitance means including a sensing capacitor having a plurality of spaced capacitive sensor conductors mounted with the insulator means for exposure to the atmosphere; and first and second electrodes mounted with the insulator means remote from the spaced capacitive sensor conductors; means for applying a periodic input current across the first and second electrodes; and means for detecting a change in capacitance between the first and second electrodes indicative of moisture bridging at least two of the capacitive sensor conductors.
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Citations
25 Claims
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1. A capacitive moisture sensor comprising:
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an insulator; a sensing capacitor having spaced capacitive sensor conductors mounted with said insulator for exposure to the atmosphere; first and second electrodes mounted with said insulator remote from said spaced capacitive sensor conductors; and circuitry connected to apply a current to said first and second electrodes and to detect a change in capacitance between said first and second electrodes indicative of moisture bridging two of said capacitive sensor conductors. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A capacitive moisture sensor comprising;
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insulator means; capacitance means including a sensing capacitor having a plurality of spaced capacitive sensor conductors mounted with said insulator means for exposure to the atmosphere; first and second electrodes mounted with said insulator means remote from said spaced capacitive sensor conductors; means for applying a periodic input current across said first and second electrodes; and means for detecting a change in capacitance between said first and second electrodes indicative of moisture bridging two of said capacitive sensor conductors.
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16. The capacitive moisture sensor of claim further comprising a reference capacitor mounted on said insulator means, and in which said means for detecting includes a phase detector responsive to said reference capacitor and said sensing capacitor for determining a phase difference representative of precipitation bridging two of said capacitive sensor conductors.
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17. A capacitive moisture sensor comprising:
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insulator means; capacitance means including a sensing capacitor having a plurality of spaced capacitive sensor conductors mounted with said insulator means for exposure to the atmosphere, a reference capacitor including a plurality of spaced capacitive reference conductors mounted with said insulator means proximate said capacitive sensor conductors, and means for shielding said capacitive reference conductors from the atmosphere; first and second electrodes mounted with said insulator means remote from said spaced capacitive sensor conductors and third and fourth electrodes mounted with said insulator means remote from said spaced capacitive reference conductors; means for applying a periodic input current across said first and second electrodes; and means for detecting a change in capacitance between said first and second electrodes indicative of moisture bridging two of said capacitive sensor conductors. - View Dependent Claims (18, 19)
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20. A capacitive moisture sensor comprising:
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a substrate having an outside surface exposed to the atmosphere and an inside surface shielded from the atmosphere, a sensing capacitor defined by two spaced apart capacitor electrodes mounted on the inside surface of the substrate; and at least two spaced sensor conductors positioned relative to the capacitor electrodes so that moisture bridging the sensor conductors causes a change in the capacitance of the capacitor, the sensor conductors being mounted on the outside surface of the substrate and exposed to the atmosphere; wherein moisture is sensed by monitoring, through an applied current, the capacitance between the capacitor electrodes. - View Dependent Claims (21, 22, 23, 24, 25)
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Specification