The two different types of moisture meter work in different ways. Pin meters rely on electrical current to measure moisture, while pinless meters use electromagnetic waves.
Pinless moisture meters have sensors on the back of the device, measuring approximately 5x5cm(2×2″). The sensor is flat and placed against the surface of the substrate.
The circuit inside a pinless moisture meter sends out a signal via the sensor. The signal is sent out in the form of electromagnetic waves.
The waves create an electromagnetic field over the area of substrate underneath the sensor. The moisture content is worked out from the signal received back from this.
The device measures the area under the whole of the sensor.
The pinless moisture meter is capable of measuring deeper into the material than just the point at which the sensor and material meet: the signal can be transmitted up to 38mm (1½”), which means an area of, approximately, 95cm3 (5 x 5 x 3.8) is measured at one time.
Pinless moisture meters are non-invasive, meaning they do not need to penetrate the test material in any way, leaving no evidence of their use. They can also be slid easily along to take multiple readings.
