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|  Pressure Sensor   |                      Operating Principle                       |     Reference      |
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| ANEROID            | Capsule made of metal with elastic properties deflects with    | WMO (1983)         |
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| BAROCAP            | Small aneroid capsule responds to changes in pressure measured | Vaisala Met        |
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| BELLOWS TYPE       | Flexible bellows respond to changes in atmospheric pressure.   | WMO (1983)         |
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| BOURDON TUBE       | A tube of elliptical cross section changes in cross section    | WMO (1983)         |
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| HYPSOMETER         | An electrical thermometer measures the boiling point of a      | WMO (1983)         |
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