摘要 |
The moisture content of a dielectric medium is measured through the use of a capacitive probe. A first sinusoidal voltage is impressed across the material and the resulting probe current is synchronously detected under the control of a sinusoidal voltage which is in phase quadrature with the impressed voltage. Accordingly, the probe current which flows between successive zero-crossings of the quadrature voltage is integrated to provide a measure of the reactive component of the probe current which, in turn, is commensurate with moisture content.
|