Abstract
Recently direct reading reactance meter have come into general use in various industries. This paper presents a circuit functioning as a direct reading capacitance meter suitable for measuring capacitances of comparatively high-loss materials. This circuit may find a wide range of application in industry. The most important qualities required of this type of equipment are sensitivity to capacitance change, stability during continuous operation for long hours and insensitivity to any resistance change in the materials. Using this circuit, the minimum equivalent parallel resistance of a specimen which has no influence on the capacitance measurement reaches as low as 3kΩ at 2MHz.
The measuring range of capacitance is about 10-2∼103pF. Stability was observed to be within less than 0.5μA in terms of zero drift during several hours' continuous operation. And the required sensitivity is obtained in the detecting circuit. This circuit has the advantage that the measuring part can be used at a distance of some meters from the detecting part.
