Humidity is the amount of water vapor in the air. Humidity sensor is a meteorological equipment that measures humidity and air temperature in the environment and converts the data into corresponding electrical signals. Modern humidity sensors are highly adaptable and come in many shapes and sizes, from tiny sensors installed in mobile phones to larger industrial-grade systems.

How Do Humidity Sensors Work?

Typically, humidity sensors contain a humidity sensing element and a thermistor, which is used to measure temperature. There are three main types of humidity sensors, each of which monitors small changes in the atmosphere to calculate humidity. These types include:

Capacitive. Capacitive humidity sensors are linear and measure relative humidity from 0% humidity to 100% humidity. They do this by placing a small metal oxide strip between two electrodes. As the level of humidity changes, the oxide’s electrical capacity changes along with it.

Resistive. Resistive humidity sensors measure humidity through the use of ionized salts between two electrodes. The ions in the salts measure the electrical impedance of atoms. As humidity levels change, so does the resistance of the electrodes.

Thermal. A thermal sensor utilizes a dual sensor system to measure humidity. One thermal sensor is housed in a layer of dry nitrogen; the other freely measures ambient air. The resulting difference between the two measurements represents the level of moisture in the air.

Humidity Sensor Applications

Humidity sensors are used across several industries to protect equipment and ensure safe and comfortable environments. Common applications include:

Meteorology. Meteorological departments rely on humidity sensor to gauge accurate weather conditions in their respective areas.

Medical. Many lifesaving medical devices rely on humidity sensor to regulate moisture. Ventilators, incubators, sterilization equipment, and more require careful moisture regulation to ensure safe and sterile function.

Automotive. Vehicles use humidity sensor for purposes such as air intake in the engine and climate control inside the vehicle.

HVAC. Humidity sensors are critical to climate control functions found in residential, commercial, and industrial HVAC systems.

Manufacturing. Manufacturing equipment for food processing, textiles, paper, and more require humidity sensor to control the amount of moisture in the air and ensure the quality of their finished products.

Aside from those listed above, other industries that rely on humidity sensor include pharmaceutical, agriculture, electronics, and more.