In wet conditions, water molecules are adsorbed by polar group on the surface of martial. And as the humidity increases, the quantity of water molecules will be changed accordingly. The adsorbed water is gradually condensing and coming into be liquid, which is electrolyte solution with current channel quality.
With the humidity increasing, macromolecule will swell, interior free volume will be bigger, carrier will be increased and the activated energy of macromolecule polyelectrolyte counter-ions will decrease, drift mobility will increase and impedance will decrease. And then when humidity decreases, water molecules are released from ion polymer and the resistor of material will increase. The environment humidity can be monitored through testing the impedance.
Humidity sensor, as an important chemical sensor, which is widely used in fields of warehousing, industry production, and process control, environmental monitoring, home appliances and meteorology etc.
Technical parameters :
||1.5V AC(MAX, sine wave)
||0.2mW(MAX, Rated voltage)
|Nominal value &range
||31 (21～50) KΩ(60%RH, 25°C)
||Moisture absorption：≤20s Dehumidification：≤40s
Reference Circuit :