The Working of Humidity Sensor and Its Applications in Various Industries

The amount of water vapor present in the air is humidity and it can be calculated as absolute humidity and relative humidity. The relative humidity plays a crucial role in medical and industrial environments. Beyond threshold levels, an elevated value of humidity can lead to errors in weather prediction systems and malfunctioning of control systems. So, as a safety and security factor, measuring the values of humidity is important. The humidity values and air temperature can be measured with the help of humidity sensors.

What is a Humidity Sensor?

Humidity sensor can be defined as a low cost-sensitive electronic device that is used in measuring the humidity of the air. Humidity sensors are also known as hygrometers. The ways in which humidity can be measured include specific humidity, absolute humidity, and relative humidity. The two major types of humidity sensors are classified as absolute humidity Sensor and relative humidity Sensor.

Based on factors used to measure humidity, these abovementioned sensors are further classified as thermal conductivity humidity sensors, resistive humidity sensors, and capacitive humidity sensors. Some of the parameters while considering these sensors are the response time, accuracy, reliability, and linearity.

Working Principle of Humidity Sensor

As per Research Dive analyst review, humidity sensor is a significant device that helps in measuring the humidity of the surrounding. Usually, these sensors contain an element that senses humidity along with a thermistor that measures temperature. For instance, just like the sensing element for a capacitor sensor is the capacitor. In relative humidity sensor to calculate the relative humidity values, the change in electrical permittivity of the dielectric materials is measured.

The materials used in constructing resistive sensor are of low resistivity. These resistive materials are placed on upper part of two electrodes. When the resistivity value of this material changes, then the change in humidity is measured. Conductive polymers, solid electrolytes, and salt are the examples of resistive materials, which are used in constructing the resistive sensor. On the other hand, the absolute humidity value is measured by the thermal conductive sensors. Now let’s see how humidity sensors work.

Applications of Humidity Sensor

The capacitive relative humidity sensors are used for several applications for measuring humidity in printers, HVAC systems, fax machines, automobiles, weather stations, refrigerators, food processing, etc. Due to their small size and low cost, resistive sensors are used in domestic, residential, and industrial applications. Thermal conductive sensors are usually used in drying machines, food dehydration, pharmaceutical plants, etc. Some of the uses of humidity sensor in various applications are listed below.

Domestic: Controlling and sensing humidity in our offices and homes is important as higher humidity may affect the blood flow. Other areas include indoor plantation, cooking, etc.

Industrial: In industries like chemical, refineries, metal, or others where furnaces are used need humidity sensors as high humidity reduces the amount of oxygen present in the air. Other industries like paper, textile, food processing, etc. also need control of humidity.

Agriculture: Drip irrigation is an irrigation technique that needs precise moisture content for plants. In the growth of the plant, the moisture present in the soil also plays an important role. Moreover, indoor vegetation also requires humidity sensors.

Electronics & Semiconductor: A number of electronic devices are graded with a range of humidity values. Generally, this value is between 10 to 50% humidity. Also, the semiconductor fabrication plants need to maintain very accurate humidity and temperature values as even a difference of a minute can hugely impact the production.

Medical: The medical equipment like sterilizers, incubators, ventilators, etc. need humidity control. The humidity sensor is also used in biological processes and pharmaceutical plants.

All the above mentioned applications need humidity sensing and this is done using humidity sensor.

About the Author(s)

Princy A. J

Princy holds a bachelor’s degree in Civil Engineering from the prestigious Tamil Nadu Dr. M.G.R. University at Chennai, India. After a successful academic record, she pursued her passion for writing. A thorough professional and enthusiastic writer, she enjoys writing on various categories and advancements in the global industries. She plays an instrumental role in writing about current updates, news, blogs, and trends.