Title :
A digital hygrometer
Author :
Shimizu, Hiromi ; Matsumoto, Hiroki ; Masahiro, A. ; Watanabe, Kenzo
Author_Institution :
Kurabe Ind. Co. Ltd., Hamana, Japan
Abstract :
A digital hygrometer using a polyimide capacitive humidity sensor is described. The capacitance change of the sensor due to absorption of water vapor in the atmosphere is detected by a digital switched-capacitor capacitance bridge controlled by a one-chip microcomputer and is displayed as relative humidity with 0.1% resolution. The accuracy of the hygrometer which is calibrated by the two-point method, is determined solely by the temperature dependence and the long-term drift of the dielectric sensitivity of the sensor and is estimated to be 2%
Keywords :
bridge circuits; bridge instruments; computerised instrumentation; digital instrumentation; electric sensing devices; humidity measurement; hygrometers; microcomputer applications; polymers; switched capacitor networks; absorption of water vapor; dielectric sensitivity; digital hygrometer; digital switched-capacitor capacitance bridge; long-term drift; one-chip microcomputer; polyimide capacitive humidity sensor; relative humidity; two-point calibration;
Conference_Titel :
Instrumentation and Measurement Technology Conference, 1988. IMTC-88. Conference Record., 5th IEEE
Conference_Location :
San Diego, CA
DOI :
10.1109/IMTC.1988.10844
