The development of a moisture detector

The electrical properties (equivalent shunt capacity and resistance) of five samples of Douglas Fir plywood veneer were measured at moisture contents ranging from 0 to approximately 15 percent. Results were plotted as capacity vs moisture content, and the reciprocal of resistance vs moisture content. To compare the results with those predicted by the theory a plot was made of tan δ vs moisture content where δ is the phase difference between capacitive current and total current through the sample. It was shown that, above certain critical values of moisture content, both capacity and resistance can be used as an indication of moisture content. Results indicated that moisture may be bound to the wood in at least two different ways.Science, Faculty ofPhysics and Astronomy, Department ofGraduat