Relative humidity sensor


This is a thermal conductivity relative humidity sensor that uses a highly sensitive thin-film thermistor to detect differences in thermal conductivity from the amount of water vapor contained in a gas to determine relative humidity.

A thermal conductivity relative humidity sensor is one whose output changes when the thermal conductivity of the ambient (detection thermistor side) atmosphere in which it is used differs from that of dry air (compensating thermistor side), and the output signal changes in accordance with the relative humidity.

Thermal conductivity sensors using thermistors are temperature dependent, so the actual circuit design must take these characteristics into account when making temperature corrections.

Appearance of relative temperature sensor (reference shape)


– Uses highly sensitive and responsive thin-film thermistors.
(1005M t=0.1mm)
(High precision achieved by high-precision pairing of thin-film thermistors)
– Continuous measurement is possible, enabling constant monitoring of relative concentration

Measurement circuit

Since it can be used with an applied voltage of 5 V, it is compatible with general-purpose microcontrollers for consumer use.

Relative humidity sensor: Example of output characteristics of humidity detection

The output of the relative humidity sensor is temperature dependent.