SU427292A1 - CAPACITIVE SENSOR - Google Patents

Description

The invention relates to electrical measurements, fine technique and is intended to study the properties of dielectric materials.

In the known capacitive sensors containing an insulating substrate and located on its working side high-potency and piscopothetical electrodes located above the surface of the material under study, the high-potential electrode has a significant parasitic capacitance relative to surrounding objects, which reduces the sensitivity and accuracy of the sensor.

In order to increase the sensitivity and accuracy in the proposed sensor, a geometrically similar equipotential protection electrode is installed under the high-potential electrode on the non-working side of the insulating substrate.

FIG. 1 shows the proposed capacitive sensor, top view; in fig. 2 is the same; the section along A-A in FIG. one.

The sensor consists of an insulating substrate. A grounded (low-potential) electrode 2 and a high-quantized electrode 5 are deposited on the substrate. The side of the substrate / on which electrodes 2 and 5 are deposited is the working side of the sensor. The substrate is applied to the measured product by the working side. On the reverse side of the substrate, exactly under the electrode 3 is applied, for example, by sputtering an electrode 4 of equipotential protection, geometrically similar to electrode 3.

To ensure the mechanical stiffness of the sensor, the substrate on the outside of the non-working surface is filled with a synthetic compound, which, when set, forms the housing 5.

The sensor works as follows. A voltage equal in frequency - ;, amplitude and phase voltage to electrode 3 is applied to electrode 4 with respect to electrode 2;

moreover, the voltage applied to electrode 4 is removed from an auxiliary power source, which is not galvanically connected to a working source that supplies voltage to electrode 3. Since the electrodes are electric, there is no current flowing between them. The measuring device will measure the current between the electrodes 2 and 3, passing only through the working space, i.e., through the measured product. The current flowing in the non-working space (through the case 5 between the electrodes 2 4, flows along the equipotential protection circuit and is not taken into account by the measuring device.

Subject invention

A capacitive sensor containing an insulating substrate and high-potential and low-potential electrodes located on its working side, characterized in that, in order to increase the sensitivity and accuracy of the sensor, under the high-potential electrode on the non-working side of the insulating substrate, a geometrically similar to it electrode of gkvchpotential protection is installed.

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