What is a humidity sensor?

Last Update Time: 2018-12-28 16:24:46

l  The role of humidity sensors

The humidity sensor is composed of a matrix, an electrode and a humidity sensing layer, which can be used for steel, chemical, fiber, semiconductor, food, and paper making, humidity control in various industrial processes, such as clocks and watches, electronic components and equipment, and optical machinery. The current humidity sensor has the use of electrical properties that vary with the moisture absorption and dehumidification processes of wet materials, including metals, semiconductors, insulators, and other materials, the sensor made of the principle of using water vapor to make the microwave loss.


l  The types of humidity sensors

 ( 1 ) The ceramic humidity sensor is mainly composed of ferric oxide and potassium carbonate and zinc oxide and palladium oxide in the ceramic humidity sensor, sintered ceramic materials.

In the range of 0 C ~ 100C, the resistance varies linearly with the relative humidity of 0 to 30 %. In the low humidity region, the resistance varies significantly with humidity. Therefore, a practical research on this kind of sensor is carried out in order to detect the dry gas with high temperature and low humidity.


( 2 ) Humidity sensitive resistance sensor is a sensitive element that changes with the change of environment relative humidity. The most commonly used is the gasifying lithium humidity sensor resistor.


( 3 ) Humidity Sensitive Capacitance Sensor is a kind of dielectric with strong hygroscopic insulation material as capacitor, a sensitive element that changes its capacitance with the change in relative humidity of the environment. The humidity sensitive capacitance sensor usually adopts porous alumina ( AL 2O 3 ) or macromolecule hygroscopic film as hygroscopic medium to make porous alumina humidity sensing humidity Sensitive Capacitance Transducer of Polymer Film.

The humidity sensitive capacitance sensor needs alternating current, and reflects the change of relative humidity according to its capacitance change. When the frequency of power supply is tested at 1.5MHz, the capacitance of polymer film humidity sensitive capacitance sensor increases to 1.6 times when the relative humidity of the environment increases from 10% to 90%, and the output linearity is good. Polymer film humidity sensitive capacitance sensor has been widely applied due to its small influence on temperature, short response time and good stability.

If you want to know more, our website has product specifications for the sensors, you can go to ALLICDATA ELECTRONICS LIMITED to get more information