新型气体热导传感器及其应用设计

Applicable Design of New Type Thermal Conductivity Sensor for Gases

气体热导传感器是利用被测组分和参考气的热导系数不同而响应的浓度型传感器。文中介绍了一种新型气体热导传感器TCS208F的特点、结构及指标，由于其输出是微弱信号，所以设计出其信号调理电路。传感器检测到的微弱信号由测量电桥调理输出，通过集成芯片AM402中的仪表放大器进行差分放大，由于远距离传输的需要，再将电压信号送入U／I变换器转换成0～20mA的工业标准电流信号，最后再把电流信号转换为电压信号送入单片机。

Thermal conductivity sensor for gases is concentration sensor that measure the thermal conductivity coefficient of the samplied gas different from the reference gas. The characteristics and configuration of a new type thermal conductivity sensor for gases were introduceA and a signal adjust circuit was designed because of faint output signal. Applying integrated chip AM402, the output signal of wheatstone bridge was amplified, then convert amplified signal into 0 - 20 mA current signal which correspond to the normal industrial standards. Finally, 0 - 20 mA current signal is converted voltage signal for putting the signal chip microcomputer.