If your work involves shipping goods of any kind, then you know it’s important to monitor the humidity levels inside each trailer or shipping container. Shipping goods in humid conditions can cause them to become damaged in transit—for example, when food items are stored in a humid environment, they are more likely to develop mold, making them unfit for sale.
Fortunately, our team at Global Sensors is here to help you monitor the humidity in your shipping containers so you can prevent these kinds of issues. In this article, we’ll explain how humidity sensors work.
- Resistive Humidity Sensors – One of the main types of humidity sensors uses ionized salts to measure the ambient moisture levels in the air. Two electrodes connected to the salts create a current which flows through the sample. As the humidity levels change, the moisture interacts with the ions in the salts to make it easier or harder for electrical current to pass through—in other words, they change the electrical resistance. The sensors measure these changes in resistance and use this data to calculate the level of humidity.
- Capacitive Humidity Sensors – Another of the main types of humidity sensors works by measuring changes in the electrical capacity of a metal oxide strip. This strip is placed between two electrodes, and as the local humidity level changes, the strip’s electrical capacity changes in response. These devices then use the resistance of the metal strip to calculate the relative humidity in a space, from 0 to 100%.
- Thermal Humidity Sensors – A third type of humidity sensor uses temperature data to calculate the humidity. Thermal humidity sensors actually contain two sensors, one of which is exposed to the ambient air, and the other of which is housed in a sealed bubble of dry nitrogen. By measuring the temperatures in both environments, the whole sensor is able to calculate the level of moisture present in the air.
