Measurement Principle

Capacitive RH sensors consist of a ceramic substrate on which a thin film of polymer is deposited between two conductive electrodes.

The sensing surface is coated with a micropourous metal electrode, allowing the polymer to absorb moisture while protecting it from contamination and exposure to condensation. As the polymer absorbs water, the dielectric constant changes incrementally and is nearly directly proportional to the relative humidity of the surrounding environment. Thus, by monitoring the change in capacitance, relative humidity can be derived.

Product Overview

IST thin film capacitive relative humidity sensors are capable of measuring 0 to 100% relative humidity and operating at temperature ranges of -80°C to +190°C.  The humidity sensor product line features sensors with excellent linearity, low hysteresis, fast response times, and high chemical resistance.

IST provides exclusive humidity sensors with directly integrated platinum temperature sensors that cater to a wide range of applications. A variety of different layouts and connections such as SMD and wired configurations are available.