March 25, 1930.
s, LQEWE
1,751,587
ELECTRICAL HIGH RESISTANCE UNIT
Filed Aug. 27, 1925
[?ue/12W: Sigmund [one
Patented Mar. 25, 1930
1,751,587
-UNITED STATES PATENT OFFICE SIEGMUND LOEWE, OF BERLIN, GERMANY, ASSIGNOR T0 RADIO CORPORATION OF AMERICA, A CORPORATION OF DELAWARE
ELECTRICAL HIGH-RESISTANCE UNIT \ \
Application ?led August 27, 1925, Serial No. 52,885, and in Germany August 30, 1924.
This invention relates to electrical high resistances un?t for purpose of wireless teleg resistance units especiall for wireless teleg raphy. raphy and telephony, inc uding broadcasting The present invention has for its object to and more especially to resistances of this 5 kind, in which the resistance body proper provide a high-resistance unit?iv’vhich com consists of a thin conductive or poorly con plies with all the afore-enumefated require~ 55 ductive layer, which is provided upon a car ments. Other objects of my invention will rier of insulating material preferably glass. be apparent from the following detailed de The resistances of this kind, which have so 10 far been obtainable in commerce, have a number of drawbacks and disadvantages and it is the main object of my present inven tion to design a resistance which is free of all objectionable properties, which are found in
scription when read in connection with the
drawing, in which Fig. 1 diagrammatically illustrates a preferred embodiment of my in- 60 vention and Fig. 2 illustrates a modi?cation
thereof. It has been found, that a carrier of insu~
15 the resistances which are at present on the lating material, especially glass, having the market or which have been known to the art. leads connected at its ends and being covered 05
with a thin conductive layer will best meet In wireless telegraphy and other branches these requirements.
of electrical engineering high-resistance
The following methods of manufacturing units are required which must combine a the resistance unit are preferably employed 20 number of properties, which are enumerated according to this invention. in the following:
1. The resistance must be absolutely inde
pendent from the load,
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A glass-rod of small length and small diameter is connected at its‘ ends with two
2. A resistance of this kind must not have leads by fusing the same thereon. The glass is brought into a soot-producing ?ame 25 any electrical after-effects, that is at the rod ends of the resistance after the passage of a and more particularly at first a relatively 75 current there must exist no voltage of any thick deposit of soot is produced‘ at both ends, ‘at which place the leads are fused onto kind
glass-rod. Thereupon the surface of the 3. 7The capacity of the resistance, if the the glass-rod is slightly covered with soot, pref erably by simultaneously observing the tem- so frequency work, must be extremely small, porary resistance value by means of an
30 same is to be used for instance for high
4. The resistance also must not have any
appreciable self-induction,
ohmmeter. As soon as the correct value of
5. A resistance of this kind must be in resistance is reached7 the further deposit of 85 sensitive against in?uences due to tempera-_ soot is interrupted. An especial advantage of this process 85 ture and moisture, consists therein, that the heat, to which the 6. The connection of the leading-in and insulating body is exposed, will expel the leading-out conductors must be reliable to
moisture, which otherwise will essentially such an extent, that neither thermo-electri have an in?uence upon the resistance value. 40 cal, electrolytical, nor fritter-like vibrations Furthermore, there is a great advantage may take place at the places of transit, found therein, that the leads at the ends may 7. The dimensions of the resistance must be covered with~a strong layer of soot in be extremely small, in order that, when order to provide a good contact between using the resistance in connections, a compact the leads and the resistance layer proper, if 45 arrangement of the parts will be possible, no. silvering of the ends of the leads or a 8. The resistance must be of such a kind, similar treatment is employed. that it may be manufactured at a small cost. Since soot is chemically inactive, a resist In particular it has been ascertained by ob ance made in this manner will only be sub; servation, that electrical after-effects are 50 present to a high degree, which render these jected to the varying in?uences of moisture and mechanical stresses.’ In order to avoid
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I claim: 7 ' these in?uences the resistance body, which 1. The method of making a high frequency is made in the manner described, is fused air-tight into a small glass-tube surrounding resistor which consists in depositing resist the resistance body and the tube is there ance material upon an insulator encased in
upon evacuated. In this way mechanical injuries and at ‘the same time in?uences due to moisture are excluded. It is of impor tance in this case, that the ends of the carrier of the resistanceare at such a distance from the places at which the leads 'are fused into
"10 the glass-tube, that during fusing-in the
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an evacuated tube in order to make the insu 70 lator a resistor of high ohmic value which in cludes the step of vaporizing a metal em
bodied in a cylinder surrounding the insula
tor by inducing eddy currents in the cylinder and condensinn' the vapor so formed upon 75 the surface of the insulator. ,
2. The method of making a‘high frequency leads, no considerable heating of theends of resistor which consists in encasing an insulat the resistance body can take place. The afore-described process, furthermore, ing rod in an evacuated casing, surrounding possesses the great advantage, that the resist the rod with a cylinder having a conductor ance proper may be made in the open air, and connected to each end thereof, each of said may be later enclosed 'in a protective casing. conductors being a?ixed to an end of the rod This protective casing may not necessarily and passing through an end of the casing, consist of an evacuated tube. It will be su?i
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said cylinder embodying a vaporizable metal,
cient, since the effects of moisture are only of and ?nally subjecting said cylinder to high
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at its ends the devices effecting the enclosure. consists in enclosing an insulating rod in an Fig. 1 shows the construction of the afore evacuated tube, surrounding the rod with a
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subordinate importance, to eventually also frequency eddy currents whereby said rod employ a non-evacuated protective, casing surface is coated with said metal.. made from insulating material, which carries 3. The method of making a resistor which
described high-resistance unit. At the points cylinder embodying magnesium, said cylinder 2 and 3 the leads are fused into the glass-tube. having a conductor connected to each end The leads are surrounded by a strong layer thereof, each of said conductors being a?ixed
of soot as indicated at {l and 5, this layer effect to an end of the rod and passing through an ing the contact between the leads and the re end ‘of the casing, and subjecting said cylin as sistance proper, which is being deposited der to eddy currents whereby said rod surface
alongside of the surface. The layer of soot ‘is coated with magnesium. forming the resistance body is indicated by 4.'A method of ‘making a resistor which
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shaded lines upon this surface. The resist consists in disposing an insulator in an evacu ance is fused into a glass-tube 6, which may ated tube, surrounding the insulator with a be eventually evacuated by means of the cylinder having a conductor connected to each
pumping stud 7. Around the ends of the end thereof, said cylinder embodying magne insulating protective tube 6 are placed the sium, a?ixing each of said conductors to one connecting caps 8 and 9, which are conduc_ end of the insulator and passing the conduc tively connected with the leads 2 and 3 and tor through an end of the tube, and ?nally which carry, if desired, terminals serving for subjecting said cylinder "to eddy currents whereby said insulator is coated with magne the outer connection ofthe resistance. The second method of manufacture is best slum. 5. A high frequency resistor comprising an illustrated by reference to Fig. 2. ' The carrier 1 of the resistance is provided evacuated casing, an insulating rod disposed within an evacuated casing 6. A holding within said casing, an open ended cylinder wire 2’~1'is fused into the insulating body 1 disposed within said casing and surrounding and carries a cylindrically closed metal body said rod, a conductor attached to each end of 3', which may be heated, by means of eddy said cylinder and affixed to the end of the rod currents. This metallic cylinder 3’ may, for closest to said cylinder. each of said conduc instance, consist of a sheet of nickel, which tors passing through the end of the casing, has been super?cially alloyed with vapour of said cylinder embodying a vaporizable metal, magnesium. Upon heating, the alloy will and said rod surface being provided with a
evaporate and deposit upon the insulating coating of said vaporizable metal. In testimony whereof I have a?ixed my sig body 1. Also, other easily vaporizable ma . terials may be employed. The material is nature.‘ SIEGMUND LOEWE. best brought to glowing by surrounding the
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tube-6 with a 0011 through which are passed
strong currents of high frequency.v Another advantageous method of manu facture consists therein, that the body of in- .
sulating material, with the leads fused into its ends is brought together with a vapor
izable material into the surrounding protec
e
tive casing.
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