US2717299A - Temperature-dependent resistor - Google Patents

Description

Sept. 6, 1955 w. JACOBI 2,717,299

TEMPERATUREIDEPENDENT RESISTOR Filed Feb. 5, 1955 INVENTOR WEE/V62 J c 05/ BY W ATTORNEY United States Patent Ofi ice 2,717,299 Patented Sept. 6,1955

TEMPERATURE-DEPENDENT RESISTOR Werner Jacobi, Grafelfing, near Munich, Germany, as-

signor to Siemens & Halske, Aktiengesellschaft, Munich, Germany, a corporation of Germany Application February 3, 1953, Serial No. 334,831

Claims priority, application Germany February 14, 1952 12 Claims. (Cl. 201-63) This invention is concerned with a temperattire-depend ent resistor for controlling high-frequency oscillations comprising a preferably controllable resistance element disposed in a vacuumtight casing which is evacuated or filled with a desired gas.

The object of the invention is to provide such a temperature-dependent resistor which exhibits even with very high frequencies excellent properties. This means, above all, that the inductive resistance of the resistor element with its current conductors must at such frequencies be small as compared to the ohmic resistance thereof.

The invention realizes this object by the provision of a casing, for receiving the temperature-dependent resistance element, which comprises two mutually insulated potlike parts serving as current supply terminals and having aligned flangelight rims. At least the flangelike portions which are extraordinarily close together are made of metal or are at least provided with a metallic coating. The vacuumtight seal is formed by a ring-shaped insulating member disposed peripherally of the rims f the aligned flanges. The structure provides for a particularly small inductance.

The spacing between the flanges may be effected by means of a thin ring-shaped disk of mica or the like. The ring-shaped insulating member forming the vacuumtight seal may be fused glass or the like. The rims of the flanges may be cut or bevelled so as to widen the spacing therebetween peripherally thereof. The flanges are in this manner throughout the greater part of their surfaces close to each other while a suflicient peripheral space is left therebetween for providing a satisfactory vacuumtight seal.

The bottom wall of either or both of the two potlike casing parts may be formed of a suitable vitreous insulating material such, e. g., as glass or ceramic material or the like and the leads or terminals for the heater which controls the temperature-dependent resistance element may be carried therethrough. Such bottom wall may also be provided with a suitable evacuation nipple or the nipple may be formed on the metallic casing part.

The invention will now be explained with reference to the accompanying drawing which shows in simplified diagrammatic manner, partially in section, essential details of an embodiment of the new resistor device.

The resistance element 1, may be a known structure, details of which have been omitted. Numeral 2 indicates the heater which is connected to a suitable current source. The resistance element 1 is provided with ring-shaped radially extending disks 3 and 4, forming current conductors therefor. Two or more differently shaped conductors may take the place of the disks 3 and 4, and may be disposed so as to radiate spiderlike from the resistor. The disks or the conductors of other shape taking their place are connected with the two potlike casing parts 5 and 6, respectively, which are insulated from each other. The inductance of each current conductor is thereby compensated or equalized by the oppositely disposed conductor or by conductors extending radially on the opposite sides.

These current conductors are dimensioned primarily from the point of view of least heat conduction to the associated potlike casing parts. In the illustrated example, the casing parts are made of metal of good electrical conductivity. They may be made of other material and provided with a well conducting coating at least at the areas which have to be conductively connected with the resistance element.

The two casing parts 5 and 6 are provided with flanges 7 and 8 which are disposed in alignment and extraordinarily closely and accurately spaced by a ring-shaped disk 9 of thin insulating material, e. g., a mica disk. It is possible however to provide on the flanges an insulating coating in place of the mica disk, e. g., a coating of aluminum oxide.

Fused glass 10 is provided circumferentially oi the aligned flanges 7 and 8, forming a vacuumtight seal. The outer rims of the flanges are cut or beveled to widen the axial spacing therebetween so as to facilitate the forming of the seal 1%.

The bottom wall of the potlike casing part 6 may be formed by a glass plate 11 which is fused to the pointed rim of the side wall thereof. The glass plate may be a pressed or molded part of the kind customarily used in the manufacture of vacuum tubes and may be provided with the two pins 12 and 13 forming terminals for supplying current to the heater 2.

A pump or evacuation nipple 14 may be provided at a suitable point. It is however possible to provide in place of such pump nipple an evacuation tubing, e. g., a metallic tubing at the bottom wall of the metallic casing part 5, as indicated in the drawing by numeral 15.

I claim:

I. A temperature-dependent resistor device for controlling high-frequency oscillations comprising a resistance element, a heater for said element and current conductor means therefor, the inductive resistance of said element and associated current conductor means being at high frequencies small, as compared with the ohmic resistance thereof, a casing for enclosing said resistance element and said heater and current conductor means, said casing comprising two potlike members, said current conductor means extending solely within said casing and being in engagement with said potlike members at corresponding areas on the inside thereof, each potlike member carrying a flange extending from the side wall thereof, said flanges being disposed in face-to-face slightly spaced alignment, at least the areas of said potlike members which are engaged by said current conductor means and the faces of said flanges being electrically conductive to form terminals for said current conductor means, and insulating means disposed peripherally of said aligned flangelike extensions forming a vacuumtight seal.

2. The structure defined in claim 1, wherein said flanges are made of metallic material.

3. The structure defined in claim 1, comprising a metallic coating carried on said flanges to form said terminals.

4. The structure defined in claim 1, comprising an insulating layer disposed between the faces of said flanges to maintain the slight spacing therebetween.

5. The structure defined in claim 1, comprising a mica layer disposed between said flanges to maintain the slight spacing therebetween.

6. The structure defined in claim 1, comprising a vitreous material forming said vacuumtight seal.

7. The structure defined in claim 1, wherein the face of each of said flanges is peripherally beveled to form in face-to-face alignment with the other flange an outwardly widening peripheral area for said vacuumtight seal.

8. The structure defined in claim 1, comprising a plurality of members forming said associated current conductor means, said members extending within said casing from an area defined by said flanges to said resistance element along paths to cause mutual cancellation of the inductance thereof.

9. The structure defined in claim 8, comprising annular disklike elements constituting said members forming said associated current conductor means.

10. The structure defined in claim 8, comprising spiderlike elements constituting said members forming said associated current conductor means.

11. The structure defined in claim 1, comprising an insulating member forming the bottom wall of at least one of said potlike casing members.

12. The structure defined in claim 11, comprising ter minal means for said heater extending in vacuum tight manner through said insulating member.

References Cited in the file of this patent UNITED STATES PATENTS 2,129,849 Laico Sept. 13, 1938 2,215,300 Ryde Sept. 17, 1940 2,504,504 Despois Apr. 18, 1950 2,522,525 Lundstrom Sept. 19, 1950 FOREIGN PATENTS 108,637 Australia Sept. 22, 1939

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