Nippon Mining Co., Ltd.

Soar Corporation

Isao Tazawa

Chikara Tominaga

Hideo Segawa

Norihiro Kiuchi

Kenji Murakami

An electronic hygrometer and an electronic thermohygrometer both comprising oscillation means and digital operation processing means. The oscillation means of the hygrometer includes a square-wave pulse signal generator, a humidity sensor connected to the generator and which exhibits characteristics variable with the humidity change of the atmosphere, and a passive element connected to the generator and which forms a time constant circuit with the characteristics of the humidity sensor, the passive element being of a type different from the humidity sensor. The oscillation means produces square-wave pulse signals corresponding to changes in the characteristics of the sensor. The digital operation processing means of the hygrometer counts the frequency of the square-wave pulse signals output from the oscillation means and determines the humidity of the atmosphere on the basis of the counted value. The thermohygrometer further comprises a reference resistance element connected in parallel with the humidity sensor, a temperature sensor connected in parallel with the humidity sensor and the resistance element and which exhibits electric resistance variable with the temperature change of the atmosphere, and switching means which open and close the circuits of the humidity sensor, resistance element, and temperature sensor.

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Nagano, Japan

Isao Tazawa