How does a moisture meter operate?

Electrical power is easily conducted through a moist or wet environment. Because all wood contains moisture it is capable of conducting an electrical signal or voltage. A moisture meter acts as a signal generator, delivering a small electrical charge -- supplied by a battery -- into the wood fibers. The current flows between two sharp pins inserted into the wood, and internal circuitry in the meter reads the amount of resistance in the wood, much like the basic operation of an ohmmeter. The meter pins typically are one inch apart from each other and can test only a small portion of the wood, so large pieces of wood may have to be tested in a number of locations for accuracy.