US2452737A - Resistor - Google Patents

Description

Nov. 2, 1948. A. s. EISENSTEIN ET Ai. 2,452,737

RESISTOR Filed March 2l, 1944 ALBERT S E/ EN TE/N KENNETH J GERMESHAUSBV BY MCD/@ Patented Nov. 2, 1948 RESISTOB Albert S. Eisenstein, Cambridge. and Kenneth J. Germeshausen, Newton Centre, Mass., assignors, by mesne assignments, to. the United States of America as represented by the Secretary of War Application March 21, 1944, Serial No. 527,498

(Cl. B01-63) 2 Claims. l

This invention relates to a resistor and particularly to a non-inductive type resistor adapted for use at high frequencies. The principal object of this invention is to provide resistance which will have negligible inductive reactance at high frequencies. This provision is desirable for such purposes as oscilloscopio study of Wave forms. The resistance is embodied in a short section of coaxial line.

This invention contemplates current flow through an infinite number of radial resistance paths extending between the inner and outer conductors of a coaxial line so that contiguous magnetic fields associated with adjacent paths of current flow will oppose each other and tend to cancel.

In the drawing, Fig. l is a View, partly in section, of the invention, and Fig. 2 is a sectional View on the line 2-2 of Fig. l.

Referring now to the drawing, the resistor is shown as a section of coaxial cable. The resistor has an outer sleeve E, which may be internally threaded throughout its length for ease in manufacture. e. resistance element E in any desired form such as a disc of a resistance compound as carbon or the like is exteriorly threaded for enn sagement with sleeve 5 and is disposed centrally Within the sleeve. Resistance element S may assume any form so long as a resistance path radially 4 from the inner conductor to the outer one is provided. Element t thus has its peripheral surface in conducting contact with an annular portion oi sleeve E. The resistance element may have any desired thickness along the sleeve axis. Resistance element 'l may also be in loose powdered form, if desired. End plugs l] of insulating material are externally threaded for engagement with the sleeve and are disposed within the sleeve in abutting relationship to resistance element on opposite sides thereof. Plugs l are 'provided with recesses 3 and Q adapted to receive a Spanner wrench for assembling the above-described memhere.

A solid metallic conductor lll is disposed axially within sleeve 5 and supported in spaced relation to the sleeve by resistance element 6 and insulat ing plug l. Conductor lo has an annular portion oi its surface in conducting contact with element Conductor it may be rigidly secured in ren slstance element E if the latter is solid. The end of conductor il) has an axial bore ll to telescope the central conductor of an associated cable coupling.

Cable coupling construction is provided for each end of sleeve 5. This coupling construction,

which may be of conventional design, comprises coupling sleeve I5, threaded at one end for engagement with internal threads of resistor sleeve 5, and having an annular externally threaded iiange IB disposed about the sleeve inwardly of its other end. An insulating bead Il disposed centrally within sleeve l5 rigidly supports a central conductor coupler i8 in spaced relation to the sleeve. Coupler I8 has end I9 reduced in section to telescope bore il of conductor Hl, while the other end has an axial bore 2U to receive the central conductor of a coupled coaxial cable. The ends of conductor i0 may be suitably shaped to provide smooth surfaces for high frequency current ilow at the junction points. A connecting coaxial cable may include solid central conductor 25 and woven metallic spaced outer conductor it maintained in any usual manner. A metallic ferrule 2l, having an annular ilange 22 at one end, encloses the end o outer conductor 25 and is rigidly joined thereto as, for example, by solder. Outer conductor 2li with its associated errule 2l lits snugly over the end o sleeve l5 and shuts annular flange le. A ring nut EQ, lnteriorly threaded for engagement with 'flange i6, has an inwardly extending annular ilange 3 l, which engages flange on the ferrule to loci; the coupled coaxial cable to sleeve i5. `inner conductor snugly telescopes axial bore Si@ of coupler i8 to complete the coupling. In many instances the frequencies are low enough to use open wire in which case any suitable mode of connection to the resistor may be employed.

The enlarged sectional view, Fig. 2, shows a number of radial arrows 35, which represent the infinite paths ol current ilow through resistance element t between inner conductor lli and outer conductor sleeve .arrows 3Q around the respective arrows 3&3 indicate diagrammatically the magnetic ilus: associated with each current path. it Will oe seen that contiguous circular paths of magnetic iiux about adjacent radial current paths are opposite in direction, and hence adjacent fields will cancel. Consequently, there is no appreciable inductive reactance.

It will be noted that the distance between insulatina spacer plugs l may ce varied to meet requrements of high irequency transmission. Sooalled bead spacing formulae to reduce reflections are well known and may be used. Or resistor t may be thin enough so that plugs 'l may be considered as one unit for reflection purposes.

l-Iaving thus described the invention, what We claim as new and desire to secure by Letters Patent is:

1. A non-inductive resistance comprising an internally threaded outer metallic sleeve, an externally threaded annular resistance element disposed within said sleeve and in threaded engagement therewith, and a central conductor disposed axially within and in conducting contact with said sleeve and extending through said resistance element.

2. A non-inductive resistance comprising an outer metallic sleeve, an annular resistance elelo the resistance element and plugs being externally threaded and in threaded engagement with the sleeve.

ALBERT S, EISENSTEIN.

TH J. GERMESHAUSEN.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 464,055 Wright Dec. 1, 1891 1,086,726 Opsahl Feb. 10, 1914 1,365,481 Gilson Jan. 11, 1921 1,905,353 Potter Apr. 25, 1933 1,935,313 Feldman Nov. 14, 1933 2,081,894 Meyer et al. May 25, 1937

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