What do moisture sensors typically consist of?

Moisture sensors are designed to detect the presence and level of moisture in various materials, and they typically consist of two electrodes, often referred to as rods, that are immersed in the material whose moisture content is being measured. The functioning of these sensors relies on the electrical conductivity of the material, which changes with varying moisture levels.

When moisture is present, it can affect the electrical resistance between the two rods. The sensor measures this resistance, allowing it to infer the moisture content. This design is effective because having two immersed rods provides a clear measurement point, improving the reliability and accuracy of the readings.

Other options do not accurately represent the standard construction of moisture sensors. A single rod would not provide sufficient data regarding moisture levels as it cannot measure the difference in conductivity between two points. A flexible sensor pad might be used in different types of sensors but does not typically represent moisture sensors specifically. A circuit board with sensors could suggest a more complex device but does not reflect the typical two-rod configuration used in most moisture sensors.