A Diode Sensor for Air Temperature and Humidity Profile Measurements

Josefina Argete


An instrument package was developed for measuring four-level dry-bulb and wet-bulb temperature profiles. Germanium diodes (1N270) incorporated into a constant current circuit were used as sensing heads. Laboratory calibrations were referenced against a factory-calibrated thermistor with an accuracy of 0.25 deg C. The diodes showed a linear response over normal atmospheric temperature range and a sensitivity of about 1.8 mV /deg C. Field performance gave the following spread of values among the four psychrometers: 0.15 deg C for Td .05 deg C for Tw and 0.15 hPa for vapor pressure.

The diode psychrometers allow air temperature and humidity profile analyses over the earth-atmosphere interface wherein accuracy, flexibility in field use, and remote reading are required.

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