Choosing a Humidity Sensor: A Review of Three Technologies This discussion of the operating principles of capacitive, resisitive, and thermal conductivity humidity sensors also addresses their advantages, disadvantages, and applications

Additional significant long-term factors are the costs associated with sensor replacement, field and in-house calibrations, and the complexity and reliability of the signal conditioning and data acquisition (DA) circuitry. For all these considerations to make sense, the prospective user needs an understanding of the most widely used types of humidity sensors and the general trend of their expected performance. Definitions of absolute humidity, dew point, and relative humidity are provided in the sidebar, "Humidity Basics").