针对使用仪器检测电容型碳纳米管湿度传感器的电容信号不利于传感器的使用与推广问题,提出了一种基于555多谐振荡式电路检测的电容型碳纳米管湿度传感器.首先,分析了传感器工作原理以及检测电路的检测原理,设计并制作了电容型碳纳米管湿度传感器;然后,分别使用仪器及检测电路对传感器进行测试;最后,对传感器响应时间进行了测试与分析.实验结果表明,该传感器在环境相对湿度从11%变化到97%过程中,电容相对灵敏度为905%,输出频率相对灵敏度为889%,两者较为吻合,表明该电路能很好地将电容信号转化为频率信号输出.另外,传感器对湿度的响应时间约为4 s,恢复时间约为18 s,功耗约为12 mW,具有功耗低、响应速度快等优点.%The capacitive signals of capacitive carbon nanotube humidity sensors are usually tested by measuring instruments, which restricts the uses and developments of the sensors seriously. Focusing on this problem,one kind of capacitive carbon nanotube humidity sensor based on a 555 multivibrator was presented. Firstly, the principle of the sensor and the detecting circuit were discussed, and the sensor was designed and fabricated. Then, the sensor was tested by both the RCL apparatus and the proposed circuit, respectively. Finally, the response and recovery time of the sensor was tested. The testing results demonstrate that when the Relative Humidities (RH) surrounding the sensor change from 11％ to 97％, the capacitive sensitivity and the output frequency sensitivity of the sensor are 905％ and 889％ ,respectively. The frequency sensitivity is closed to the capacitive sensitivity, which means the circuit can well change capacitive signals to frequency signals. Furthermore, the adesorption and desorption time of the sensor is about 4 s and 18 s, respectively,which shows the sensor can offer low power consumption and fast response and has potential application prospects.
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