SU1691781A1 - Transducer for measuring specific capacitance of foil - Google Patents

Abstract

The invention relates to a control and measuring technique and can be used to measure the specific capacity of the foil in the manufacture of electrolytic capacitors. The purpose of the invention is to expand the functionality of the sensor - is achieved by changing the capacitance of the measuring electrode by a known number of times while maintaining the uniformity of the electric field at the surface of the measured foil section. The sensor contains a dielectric base 1, a measuring electrode 2, made in a spiraled coiled in a dense package of tapes 3, 4 of foil, insulated from each other by tapes 5 and 6 of a dielectric, a guard electrode 7, made of foil in the form of a coiled tape 8, insulated tape 9 The measuring and guard electrodes are insulated from each other by a tape 10, the leads 11 from the guard electrode, 12 and 13 from the tapes 3 and 4 of the measuring electrode are brought out through the holes 14,15,16 of the dielectric base 1. 1 Il.

Description

The invention relates to a measurement and control technique in capacitor-capacitance and can be used to measure the specific capacity of the foil used to manufacture electrolytic capacitors.

The purpose of the invention is to expand the functionality of the sensor by changing the capacitance of the measuring electrode by a certain number of times while maintaining the uniformity of the electric field at the surface of the foil being measured.

The drawing shows a sensor for measuring the specific capacity of the foil.

The sensor contains a dielectric base 1, the measuring electrode 2, made in the form of coiled spirally in a dense package of two tapes 3, 4 of foil,

isolated from each other by two tapes 5, 6 of a dielectric, guard electrode 7, made in the form of a foil tape coiled in a spiral 8, the turns of which are separated by a dielectric tape 9.

The measuring and guard electrodes are insulated from each other by a tape 10 of a dielectric. Pins 11 from the guard electrode, pins 12 and 13 from the tapes 3 and 4 of the measuring electrode are brought out through the holes 14, 15 and 16 of the dielectric base 1.

Measuring the specific capacitance of the foil using a sensor is as follows. A sensor in the electrolyte is placed near the surface of the foil being measured parallel to it. The surface of the measuring 2 and guard 7 electrodes should be at that distance from

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the surface of the foil so that there is no contact between the sensor electrodes and the foil. The maximum distance is determined by maintaining the uniformity of the electric field in the measurement zone near the foil surface, i.e. it depends on the width of the guard electrodes and the measuring range of the tangent of the dielectric loss angle of the measuring instrument, since the resistance of the electrolyte volume between the measuring electrode and the measured foil portion active loss resistance of the measured capacitor. The foil is connected to one terminal of the device for measuring capacitance, and the terminals 12 and 13 of the sensor are connected to another.

The first measurement of the capacitance is carried out, and a potential equal to the potential of the measuring electrode 2 is maintained at the guard electrode 7.

Then one of the pins 12 or 13 is disconnected from the capacitance measuring device and similarly the second measurement of the capacitance is carried out. Then, the results of two measurements determine the capacity of the measured foil area.

g, CiC2 (n-1)

 nCi-C2 where Cf is the capacity of the foil;

Ci, C2 - the results of the first and second measurements of the capacitance;

n is the relative coefficient of change in the capacitance of the measuring electrode. And, if necessary, determine the capacitance of the measuring electrode C

g - C1 ° 2 (p 1) Cu n (C2-Ci)

To improve the accuracy of measuring the current density through the measuring electrode 2 during the first and second measurements, it is necessary to maintain the same. This is explained as follows. When a certain amount of electricity is communicated to the electrode, a corresponding change in the potential of the electrode occurs, which causes a change in the capacitance of the double layer. Preserving the current density through the measuring electrode 2 during the first and second measurements causes the same specific amount of electricity to be transmitted, i.e. double layer capacity will be the same. Therefore, the used capacity of the measuring electrode 2 at

disconnecting pins 12 or 13 will be halved.

The uniform distribution of the surface of the measuring electrode 2 and the alignment of the non-uniformity of the electric field leads to the fact that the area of the foil being measured is maintained. The capacity of the measured foil area during the second measurement will remain practically unchanged,

although the current density through it changes in proportion to the change in the surface of the measuring electrode 2. This is due to the fact that foil is used to manufacture electrolytic capacitors

of valve metals (e.g. aluminum), which are always coated with a layer of oxide, natural or artificial, the oxide being a semiconductor material, and the capacitance of the semiconductor solution is determined directly by the properties and thickness of the semiconductor material. The surface of the measuring electrode 2 is the surface of the ends of the tapes 3, 4 of the foil during the first measurement and the tape

3 (or ribbons 4) in the second dimension, facing, when measured, toward the foil. Using a sensor to measure the specific capacity of the foil improves the accuracy of measuring the specific capacity.

foil, as directly from the results of two measurements, you can determine the parameters of the measuring electrodes and take them into account when accurately determining the specific capacity of the foil. Ability to determine

the parameters of the measuring electrodes without additional means reduces the requirements imposed on the measuring electrodes of the sensors, namely, to the size of the capacitance of the double layer of the measuring electrodes.

Claims (1)

Claims of the Invention A sensor for measuring the specific capacity of a foil comprising a dielectric base and placed on it in one the plane of the measuring electrode, made in the form of a flat cylinder, and the protective electrode surrounding it, electrically isolated from each other, distinguish — i h. the functionality of the sensor, the measuring electrode is made of two spiral-wound foil strips, isolated from each other by two dielectric tapes. L //