How does a resistive humidity sensor work?

Humidity sensors work by detecting changes that alter electrical currents or temperature in the air. Resistive humidity sensors utilize ions in salts to measure the electrical impedance of atoms. As humidity changes, so does the resistance of the electrodes on either side of the salt medium.

What is a resistive humidity sensor?

Resistive humidity sensors measure the change in electrical impedance of a hygroscopic medium such as a conductive polymer, salt, or treated substrate. Resistive sensors are based on an interdigitated or bifilar winding. The impedance change is typically an inverse exponential relationship to humidity.

What is the function of humidity sensor?

The humidity sensor is a device that senses, measures, and reports the relative humidity (RH) of air or determines the amount of water vapor present in gas mixture (air) or pure gas. Humidity sensing is related to a water adsorption and desorption process [82].

What is the principle of operation of a resistance hygrometer?

Resistance-type hygrometer The resistance-type hygrometer utilizes the principle that electrical resistance varies in a material that absorbs moisture. Special resistive sensors measure the electrical resistance between the electrodes.

What is the working principle of a humidity sensor?

Working Principle of Humidity Sensor Relative humidity sensors usually contain a humidity sensing element along with a thermistor to measure temperature. For a capacitive sensor, the sensing element is a capacitor. Here the change in electrical permittivity of the dielectric material is measured to calculate the relative humidity values.

What’s the difference between capacitive and resistive humidity sensors?

However, the mechanism in this system is different. Although resistive sensors use a hygroscopic (moisture-absorbing) material similar to the capacitive system, the difference is that the measurement is of the resistance change in the material rather than the capacitance.

Which is an example of a resistive sensor?

Change in the resistivity value of this material is used to measure the change in humidity. Salt, solid electrolytes and conductive polymers are the examples of resistive material used in Resistive sensor. Thermal conductive sensors measure Absolute humidity values.

What is the relationship between humidity and resistivity?

The Resistive Humidity Sensor is usually made up of materials with relatively low resistivity and this resistivity changes significantly with changes in humidity. The relationship between resistance and humidity is inverse exponential.