Humidity sensor has the following characteristics

Humidity sensor has the following characteristic1 , precision accuracy and long term stability of the humidity sensor should reach ± 2% ~ ± 5% RH, hard to reach this level of use as measuring instruments , humidity sensors to achieve ± 2% ~ ± 3% RH accuracy is relatively difficult, given the characteristics of the product information usually is at room temperature (20 ℃ ± 10 ℃) and the clean gas measurement. In actual use, due to dust, oil slicks and harmful gases , use over time may deteriorate accuracy down to the level of accuracy of the humidity Crankshaft Positioning Sensor to determine the long-term stability of their combination , in general , and the use of long-term stability life is a top issue affecting the quality of the humidity sensor , the annual shift of control in 1% RH level products rarely , usually within ± 2% , or even higher.
2, the temperature coefficient of the humidity sensor and humidity sensor in addition to the environmental moisture-sensitive , but also sensitive to temperature , the temperature coefficient is generally in the 0.2 ~ 0.8% RH / ℃ range, and some of the humidity sensor at different relative humidity , there are differences in temperature coefficient . Drift nonlinearity, which requires additional temperature compensation in the circuit. Humidity Crankshaft Positioning Sensor using SCM software compensation , with or without temperature compensation is not guarantee the accuracy of the whole temperature range , the linearization curves humidity sensor drift compensation directly affect the results , nonlinear drift compensation is often no better results only the use of hardware temperature compensation will obtain the true follower of the compensation effect . Humidity sensor operating temperature range is also an important parameter. Most humidity sensor is difficult to work in more than 40 ℃.
3 , when applying a direct voltage supply of metal oxide ceramic humidity sensors , and polymer materials such as lithium chloride humidity will cause performance changes, or even fail , so these can not be the humidity sensor with a DC voltage or a DC component AC voltage. Must be AC powered.
4 , interchangeability Currently , the humidity sensor interchangeability difference in the prevalence of the phenomenon , the same type of sensor is not interchangeable , seriously affected the results, to maintenance, testing increased the difficulty , some manufacturers have made efforts in this regard , ( but still very poor interchangeability ) achieved good results .
5 , the humidity correction correction correction temperature and humidity is much more difficult than that . Temperature calibration is often used as a standard to a standard thermometer , and humidity calibration standard is more difficult to achieve , wet and dry bulb thermometer and hygrometer some common pointer is not used for calibration , the accuracy can not be guaranteed , because of its environmental requirements very stringent conditions are , in general , ( preferably under conditions suitable humidity ) in the absence of the test sound device , usually a saturated salt solution with a simple test method , and the measured temperature.