Common

Comparison of Humidity Sensors – Industrial Instruments

The humidity sensors come in various types and are used to measure the moisture content in the air.

Comparison of Humidity Sensors

The table outlines the key features of commonly used types of humidity sensors:

Parameter	Capacitive	Resistive	Thermal Conductivity	Gravimetric	Psychrometer	Optical	Hair Hygrometer
Principle of Operation	Dielectric constant varies with humidity	Resistance varies with moisture	Thermal conductivity varies with humidity	Absorbed water weight	Wet-bulb and dry-bulb temperature difference	Light scattering or absorption	Hair length changes with humidity
Humidity Range	Wide (0 to 100%)	Moderate (10 to 90%)	Wide (0 to 100%)	Limited (20 to 90%)	Wide (0 to 100%)	Moderate (20 to 90%)	Wide (20 to 100%)
Accuracy	High	Moderate	Moderate to High	Very High	Moderate	Moderate	Low to Moderate
Response Time	Fast	Moderate	Moderate	Slow	Moderate	Fast	Slow
Sensitivity	High	Moderate	Moderate	High	Moderate	Moderate	Low
Cost	Moderate to High	Low	High	Very High	Low to Moderate	Moderate to High	Low
Temperature Sensitivity	Moderate	High	Low	Moderate	Moderate	Low	Moderate
Maintenance	Low	Moderate	Moderate	High	Moderate	Low	Moderate
Ease of Installation	Easy	Moderate	Moderate	Difficult	Moderate	Moderate	Easy
Safety Aspects	Generally Safe	Generally Safe	Generally Safe	Generally Safe	Generally Safe	Generally Safe	Generally Safe

Here’s a brief explanation of the terms used:

Principle of Operation: The underlying mechanism or physics that allows the sensor to measure humidity.
Humidity Range: The range of humidity levels the sensor can accurately measure.
Accuracy: The level of precision in humidity measurement.
Response Time: How quickly the sensor can respond to changes in humidity.
Sensitivity: How much the output changes for a given change in humidity.
Cost: The relative cost involved in purchasing and installing the sensor.
Temperature Sensitivity: The sensor’s responsiveness to changes in temperature, which may affect its accuracy.
Maintenance: The level of upkeep required to keep the sensor in optimal condition.
Ease of Installation: How easy or difficult it is to install the sensor.
Safety Aspects: Safety considerations, are mainly relevant if the sensor is used in hazardous or extreme conditions.