General Info on capacitive humidity sensors

Construction

A capacitive humidity sensor in principle works like a classic plate capacitor. The lower electrode is deposited upon a carrier substrate. A thin polymer layer acts as dielectric. The upper capacitor plate is configured as electrode which is transmissive to water vapor.

The polymer layer is susceptible to water intake, we call that "hygroscopic". Water molecules can go into this layer and alter its dielectric constant and thus the resulting capacity value of the capacitor. This change in capacitance then can be measured and further evaluated by the users application circuit.

Variety of terminal configurations and capacities

Needless to say, that IST as a quality house is in a position to provide you a variety of terminal configurations. Wire terminals of various length, SIL, DIL-pin-outs, as well as various SMD layouts for fully automated pick & place handlers cut down design-in times. We readily support your custom designs, e.g. with integration of other sensor and heater elements to one chip for better thermal coupling and in sensor elements on your electronically adapted capacities.