Investigation of a variable-gain circuit for hydrogen detector

• Main Authors: Chia-Jung Chen, 陳佳蓉
• Other Authors: Kun-Wei Lin
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/92400931422928360611

碩士 === 朝陽科技大學 === 資訊工程系碩士班 === 97 === In this thesis, a 3×3 gas sensors array with on chip multiple input integrated circuitry by using microelectromechanical system (MEMS) was fabricated. Hydrogen sensors fabricated with different structures can be measured simultaneously. The hydrogen sensing chip has two advantages. First, the structure of the array has a cantilever beam, it can prevent the hot effect. Second the fabrication can consistent with CMOS technology. It’s easy to measure and analysis by using the chip with variable-gain.Traditionally, the hydrogen sensing device and the sensing chip were divided. It will restrict the application due to the noise at the interface between the device and chip. Our device integrate the hydrogen sensing device and sensing circuit on the same chip. Palladium (Pd) is selected as the catalytic metal. Further more in contrast to the conventional amplifier, using resistance-ratio, our design amplifier base on capacitance-ratio can prevent the influence of fabrication parameters. The DC offset also can be improved. Finally, the designed circuit has the advantages of low cost and low power consumption.