ABSTRACT
The thermal conductivity–based hygrometer method uses the influence of water vapor on the thermal conductivity of the air. These devices measure the absolute humidity by quantifying the difference between the thermal conductivity of dry air and that of air containing water vapor. Typically, thermal-conductivity cell with a Pt wire is used for this purpose. The description of the design and operation principles of such sensors can be found in this chapter. Here, we also consider the various approaches used to develop such sensors. It is shown that, besides conventional approaches, thermal conductivity–based hygrometers can be manufactured using micromachining technology. Advantages and disadvantages of these sensors and their parameters are also analyzed in this chapter.
