通常用的湿度传感器都是电压、电流输出类型,因此对湿度的检测一般都需要先通过毫伏放大器,将微弱输入信号给予放大,然后经过模数转换芯片,将模拟信号转换为数字信号,再送给计算机去进行处理。本文介绍一种阻抗输出薄膜式湿度传感器的湿度监控仪,是利用湿度传感器、电容、与非门构成单稳态电路,将湿度的变化所相应的阻抗值变化变换为单稳态电路输出的脉宽变化,然后由单片微机对脉宽进行计数,变换成了数字量的变化。这种湿度监控仪具有简单、经济的特点。由于它将单片微型计算机MCS-51的8031作为控制部件,这就使本仪器具有抗干扰能力强、可靠性高、体积小等特点。因此本仪器具有一定的推广使用价值。我们使用的湿度传感器是广泛应用于气象部门,放于气球中测量室外大气中空气湿度的肠衣薄膜式湿 Humidity sensors are commonly used voltage and current output type, so the humidity detection generally need to pass through the millivolt amplifier, the weak input signal to give amplification, and then after the analog-digital conversion chip, the analog signal is converted to digital signals, and then sent To the computer for processing. In this paper, a humidity monitoring instrument of impedance output film humidity sensor is introduced, which uses the humidity sensor, capacitor and NAND gate to form a monostable circuit to transform the change of the impedance value corresponding to the humidity change into the pulse output from the monostable circuit Wide change, and then by the single-chip computer to count the pulse width, transformed into a digital change. This humidity monitor is simple and economical. Because it will be single-chip MCS-51 8031 ​​as a control unit, which makes the instrument with anti-interference ability, high reliability, small size and so on. Therefore, the instrument has a certain value to promote the use. We use the humidity sensor is widely used in the meteorological department, placed in the balloon to measure the atmospheric humidity in the air outside the casing film wet