| 摘要 |
The tester has a probe to be inserted into granular or fluid materials for measuring instantly permittivity and temperature. The characteristics of materials are measured according to permittivity, the characteristics of moisture of grains being used as an example in the present embodiment. Features of the tester include: a sensing capacitor within a tip of the probe being an extension of a printed circuit board mounted within a main casing of the probe, an adjustable printed-circuit type capacitor as a reference in cooperation with the sensing capacitor in a balanced input circuit, touch-type switches to which battery is continually supplied to select instantly different calibrations for different characteristic curves without operation of any other switches, and the use of voltage dividers selected by the switches to provide a voltage for zero crossing and another voltage to adjust gain according to the slope of a desired curve, the voltages from a voltage divider for different gains being varied as a function of temperature at the probe.
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