Capacitive Water Vapour Sensors

Capacitive water vapour sensors measure relative humidity (RH) by observing changes in capacitance between conductive electrodes. The sensor works like a plate capacitor with the bottom plate under a thin polymer hygroscopic dielectric. The plate above this allows water vapour to pass throughout polymer until it reaches equilibrium with the gas under measurement. The dielectric strength of the polymer is proportional to the water vapour content and this directly controls its capacitance. A simple temperature measurement allows the absolute humidity to be deduced. At Versaperm we are not tied to any specific sensor types or manufacturer and so we can always select exactly the right sensor for an application. Versaperm is a world technology leader in the measurement of gas permeability. We offer not only instruments but also comprehensive testing and consultancy services.