Humidity sensors

Humidity and temperature sensors

Humidity and temperature sensors (or hygrometer) are designed to measure both humidity and air temperature. The ratio of air humidity to the greatest amount of moisture at a certain air temperature is called relative humidity.

There are three main types of humidity_sensors:

• capacitive
• resistive
• thermal

Capacitive humidity_sensors

A capacitive humidity sensor measures relative humidity by placing a thin strip of metal oxide between two electrodes. The electrical capacitance of a metal oxide varies with the relative humidity of the atmosphere. Meteorology, commerce and industry are major applications.

Resistive humidity_sensors

Resistive humidity_sensors use ions in salts to measure the electrical resistance of atoms. As humidity changes, the resistance of the electrodes on both sides of the saline environment changes.