Title :
Electric conductimetric sensor with a thin-layer structure for moisture analysis
Author :
Mitsubayashi, Kohji ; Miyoshi, Yoko ; Takeuchi, Toshifumi ; Karube, I.
Author_Institution :
Dept. of Human & Inf. Sci., Tokai Univ., Kanagawa, Japan
Abstract :
An electric conductimetric sensor (thickness: 80 μm) constructed in a sandwich configuration with a hydrophilic poly-tetrafluoroethylene membrane placed between two gold deposited layers was evaluated for use as a moisture sensor. The humidity level was measured by electrical conductivity of the device using the Multi-frequency LCR-meter at frequencies ranging from 100 Hz to 100 k Hz, the device was calibrated at 100 Hz against the moisture air over the range of 30-85 % RH, which includes normal humidity level in the atmosphere and physiologic air such as breath and sweating. The response sensitivity of the conductimetric device was extremely high (i.e. less than 1 sec. for conductivity shift between humid air of 80 % RH and dried air of -60 °C dew point) even for recovery to dried air. The sensor performance was reproducible over multiple measurements, showing the highly reproducibility with a coefficient of variation of 1.77 % (n = 5).
Keywords :
electric sensing devices; electrical conductivity; gas sensors; humidity; humidity measurement; humidity sensors; organic compounds; -60 degC; 100 Hz to 100 kHz; 80 % RH; 80 mum; Multi-frequency LCR-meter; breath; coefficient of variation; conductimetric device; conductivity shift; dried air; electric conductimetric sensor; electrical conductivity; gold deposited layers; humid air; humidity level; hydrophilic poly-tetrafluoroethylene membrane; moisture air; moisture analysis; moisture sensor; multiple measurements; normal humidity level; physiologic air; response sensitivity; sandwich configuration; sensor performance; sweating; thin-layer structure; Atmosphere; Atmospheric measurements; Biomembranes; Conductivity measurement; Electric variables measurement; Frequency measurement; Gold; Humidity measurement; Moisture measurement; Reproducibility of results;
Conference_Titel :
Optoelectronic and Microelectronic Materials and Devices, 2002 Conference on
Print_ISBN :
0-7803-7571-8
DOI :
10.1109/COMMAD.2002.1237231