Johnson Controls Technology Company

Johnson Service Corp.

Gary F Oman

Paul H Froehling

Paul E Thoma

Jeannine O Colla

Bruce R Schultz

Carl F Klein

Scott L Spence

Arthur Barootian

Ivshin Yefim

George Lewis

Kurt A Hoefert

A humidity detector has a sensor with an electrical characteristic that varies as a function of humidity and a transmitter circuit which produces an output signal in response to the capacitance of the sensor. The humidity detector is calibrated by alternately connecting devices in place of the sensor which simulate performance of the sensor at two reference humidity levels. While each device is present, the transmitter circuit is adjusted so that the output signal indicates the respective reference humidity level. Next, the sensor is connected to the transmitter circuit and exposed to a known humidity level. Then the transmitter circuit is adjusted so that the output signal indicates the known humidity level.

Humidity detector calibration method

A capacitance elastomeric pressure sensor includes top and bottom mounting plates arranged to support a pair of electrode layers. The first electrode layer is supported on the upper surface of a dielectric disc held by an upper mounting plate. The second electrode layer is located beneath the disc and includes a conductive elastomeric layer overlying an elastomeric support layer. In the preferred embodiment, the elastomer is a silicone elastomer and the conductive layer is formed by admixing a conductive carbon powder with the silicone. The sensor is particularly effective in sensing pressure changes in this low range, e.g. 0-1 inch of water. In the most preferred embodiment the elastomeric layer is prestrained for temperature compensation.

Elastomer type low pressure sensor

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New Berlin, WI, United States of America

Gary F Oman