Glossary · Sensors and measurement
Humidity sensor
Also known as: Hygrometer, Moisture sensor
German: Feuchtesensor
In measurement technology, a humidity sensor is a sensor that measures the water vapor content of air or gases, usually as relative humidity or dew point, most commonly with a capacitive or resistive sensing element.
- Sensors
In one sentence
A humidity sensor measures the water vapor content of air or gases, usually as relative humidity or dew point.
Example
A humidity sensor in a control cabinet triggers the heater before condensation can form on the electronics.
How it applies
- Engineering: Relative humidity depends strongly on temperature, so humidity sensors usually include a temperature sensor, and dew point is calculated from both. For compressed air and gases, dew point is the more meaningful value.
- Installation: Place the sensor where it represents the air of interest, away from heat sources, direct sprays and dead zones. Filters protect the element but slow the response.
- Maintenance: Humidity elements drift, especially in contaminated air or at high humidity. Recalibration or replacement intervals should be defined.
- Documentation: State whether a value is relative humidity, dew point or absolute humidity, and at which temperature and pressure. The engineering unit alone is not enough to interpret it.
Humidity vs. moisture
Humidity usually refers to water vapor in air or gases. Moisture of solids, such as grain or wood, is measured with other methods, even though the terms are sometimes used interchangeably.