SU1702442A1 - Variable capacitor - Google Patents

Abstract

This invention relates to radio engineering, in particular, to designs of variable capacitor electrical capacitors. The aim of the invention is to expand the limits of adjustment (capacity and increase its reliability. The capacitor contains a disk of dielectric material, the two sides of which are conductive layers that serve as electrodes. One of them is divided into sections by radial slots that do not reach the edge of the base and electrically connected to each other at their bases. Changing the capacitance of a capacitor is carried out by cutting the electrode sections at their base and disconnecting them from the current lead. It does not increase the resistance of a capacitor to mechanical shock and vibration loads. 1 Il.

Description

The invention relates to radio engineering, in particular, to designs of electric capacitors of variable capacity with a mechanical drive.

The aim of the invention is to expand the limits of capacity adjustment and increase its reliability.

The drawing shows the design of a capacitor.

The capacitor contains a disk 1 made of ceramic or another dielectric, a layer 2 of conductive material deposited on the upper surface of the disk 1, forming a single plate (plate) of the capacitor (this layer can be applied to the disk in various ways, for example by spraying), layer 3, similar to layer 2, deposited on the lower surface of the disk and forming the second lining (plate) of the capacitor, the radial slits 4 in the conductive layer 2, not reaching the rim of the disk and dividing it into sectors electrically connected to each other and with the current lead only at its bases, in the area of the rim of the disk, in the lower conductive layer 3 such slots are not made, the hole 5 in the disk 1 and the conductive layers 2 and 3. cutter 6, trajectory 7 of the cutter movement, indicated by a dotted line in the drawing, corrugation 8, and in some cases also digitization on the disk rim, the current lead 9 of the upper layer (plate) of the variable capacitor. The corrugation is necessary with such a constructive version of the device when the cutter is stationary and the disk 1 rotates relative to it, a part of the corrugated rim of which comes out through the corresponding window on the radio panel and is used to carry out a manual drive when changing capacitance (like adjustment knobs widely used in portable transistor radio receivers) .

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Digitizing on the rim of a disk allows you to precisely set the required capacity value and thus realize one of the most important advantages of this design: the ability to precisely set the required capacity and make any amount of smooth adjustment of its value within the real accuracy of the mechanical drive.

If the disk 1 is made of a very hard material, for example ceramic, then cutting the conductive layer to cut off the sectors is difficult (it does not form necessary for a reliable groove separation). In this case, the disk can be made of a composite by placing throughout the entire trajectory of the expected movement of the cutter an annular substrate made of a softer dielectric.

Conductive layers 2 and 3 may be covered with a protective layer of any material that does not create insurmountable difficulties for the cutter to move. The number of sectors into which conductive layer 2 is divided may be any, depending on the required smoothness and accuracy of capacitance control.

The capacitor capacitance is changed as follows.

When the disk 1 rotates, the cutter 6 cuts the sectors of the conductive layer 2 at their base, disconnects the latter from the current lead 9 and thereby irreversibly reduces the capacitance of the capacitor. The slits in the conductive layer 2 resulting from the movement of the cutter 6 do not reduce the reliability of the device, since they only occur in the disconnected sectors. In addition, this structure is easily sealed. In the production process of variable capacitors to prepare

their values to the desired nominal are used technological operations, with the aim of reducing the area of capacitor plates. Such operations are performed with a special tool.

In this case, the operation of changing the area of capacitor plastics is performed on the finished capacitor during the period

its operation in the equipment. Structurally, this is achieved by inserting a special tool (cutter, abrasive, etc.) into the capacitor, which is an integral part of the capacitor.

Thus, the advantage of this capacitor design is the extremely wide range of capacitor capacitance changes and the increased resistance to mechanical stress.

shock and vibration loads. In addition, it creates the possibility of substantial miniaturization of such variable capacitors up to the size of constant capacitors of the same capacity.

Claims (1)

Claims of variable capacitor, mainly for disposable equipment, made in the form of a dielectric base, on both sides of which conductive layers are applied, which serve as electrodes, equipped with a current drain and a mechanical drive, characterized in that, in order to expand limits of capacity adjustment and increase of its reliability, one of its electrodes is divided into sections by radial slots that do not reach the edge of the base and are electrically connected to each other and with a current lead at its bases, and is equipped with a cutting tool that serves to disconnect the electrode sections from the current lead.