US3353134A - Resistive element and variable resistor - Google Patents
Resistive element and variable resistor Download PDFInfo
- Publication number
- US3353134A US3353134A US389834A US38983464A US3353134A US 3353134 A US3353134 A US 3353134A US 389834 A US389834 A US 389834A US 38983464 A US38983464 A US 38983464A US 3353134 A US3353134 A US 3353134A
- Authority
- US
- United States
- Prior art keywords
- coating
- resistive element
- nickel
- percent
- chromium
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000000576 coating method Methods 0.000 claims description 32
- 239000011248 coating agent Substances 0.000 claims description 31
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 30
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 26
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 23
- 229910045601 alloy Inorganic materials 0.000 claims description 15
- 239000000956 alloy Substances 0.000 claims description 15
- 229910052697 platinum Inorganic materials 0.000 claims description 14
- 238000009501 film coating Methods 0.000 claims description 13
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 11
- 229910052804 chromium Inorganic materials 0.000 claims description 11
- 239000011651 chromium Substances 0.000 claims description 11
- 239000007888 film coating Substances 0.000 claims description 11
- 229910052742 iron Inorganic materials 0.000 claims description 11
- 229910052759 nickel Inorganic materials 0.000 claims description 11
- 229910052741 iridium Inorganic materials 0.000 claims description 7
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 claims description 7
- 229910052703 rhodium Inorganic materials 0.000 claims description 7
- 239000010948 rhodium Substances 0.000 claims description 7
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 claims description 7
- BIJOYKCOMBZXAE-UHFFFAOYSA-N chromium iron nickel Chemical compound [Cr].[Fe].[Ni] BIJOYKCOMBZXAE-UHFFFAOYSA-N 0.000 description 9
- 229910000510 noble metal Inorganic materials 0.000 description 8
- 229910000640 Fe alloy Inorganic materials 0.000 description 7
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 6
- 239000011810 insulating material Substances 0.000 description 6
- 239000004020 conductor Substances 0.000 description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- 229910052799 carbon Inorganic materials 0.000 description 4
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 4
- 229910052737 gold Inorganic materials 0.000 description 4
- 239000010931 gold Substances 0.000 description 4
- 229910001252 Pd alloy Inorganic materials 0.000 description 3
- 239000000919 ceramic Substances 0.000 description 3
- 239000011521 glass Substances 0.000 description 3
- BBKFSSMUWOMYPI-UHFFFAOYSA-N gold palladium Chemical compound [Pd].[Au] BBKFSSMUWOMYPI-UHFFFAOYSA-N 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 229910052763 palladium Inorganic materials 0.000 description 3
- 235000012239 silicon dioxide Nutrition 0.000 description 3
- 239000010409 thin film Substances 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 239000010408 film Substances 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- 229920003023 plastic Polymers 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 239000004332 silver Substances 0.000 description 2
- 238000001771 vacuum deposition Methods 0.000 description 2
- 239000004641 Diallyl-phthalate Substances 0.000 description 1
- ZKWGLKJFEZJMCS-UHFFFAOYSA-N FC(=C(F)F)F.[C] Chemical group FC(=C(F)F)F.[C] ZKWGLKJFEZJMCS-UHFFFAOYSA-N 0.000 description 1
- 229910018487 Ni—Cr Inorganic materials 0.000 description 1
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 1
- 101150062705 Wipf3 gene Proteins 0.000 description 1
- QUDWYFHPNIMBFC-UHFFFAOYSA-N bis(prop-2-enyl) benzene-1,2-dicarboxylate Chemical compound C=CCOC(=O)C1=CC=CC=C1C(=O)OCC=C QUDWYFHPNIMBFC-UHFFFAOYSA-N 0.000 description 1
- 239000005388 borosilicate glass Substances 0.000 description 1
- VNNRSPGTAMTISX-UHFFFAOYSA-N chromium nickel Chemical compound [Cr].[Ni] VNNRSPGTAMTISX-UHFFFAOYSA-N 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 239000003822 epoxy resin Substances 0.000 description 1
- LNEPOXFFQSENCJ-UHFFFAOYSA-N haloperidol Chemical compound C1CC(O)(C=2C=CC(Cl)=CC=2)CCN1CCCC(=O)C1=CC=C(F)C=C1 LNEPOXFFQSENCJ-UHFFFAOYSA-N 0.000 description 1
- 239000012774 insulation material Substances 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000005011 phenolic resin Substances 0.000 description 1
- 229920001568 phenolic resin Polymers 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 125000006850 spacer group Chemical group 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C10/00—Adjustable resistors
- H01C10/30—Adjustable resistors the contact sliding along resistive element
- H01C10/32—Adjustable resistors the contact sliding along resistive element the contact moving in an arcuate path
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C10/00—Adjustable resistors
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C10/00—Adjustable resistors
- H01C10/30—Adjustable resistors the contact sliding along resistive element
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C10/00—Adjustable resistors
- H01C10/30—Adjustable resistors the contact sliding along resistive element
- H01C10/301—Adjustable resistors the contact sliding along resistive element consisting of a wire wound resistor
- H01C10/303—Adjustable resistors the contact sliding along resistive element consisting of a wire wound resistor the resistor being coated, e.g. lubricated, conductive plastic coated, i.e. hybrid potentiometer
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C10/00—Adjustable resistors
- H01C10/30—Adjustable resistors the contact sliding along resistive element
- H01C10/308—Adjustable resistors the contact sliding along resistive element consisting of a thin film
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
- H01C7/006—Thin film resistors
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S338/00—Electrical resistors
- Y10S338/01—Worm gear drive
Definitions
- a resistive element has a circular base of insulating material provided with a central opening and a recess in the periphery. Adjacent the periphery the base has a thin resistance coating of a nickel-chromium-iron alloy ranging in composition by weight from 20-65 percent nickel, 15-75 percent chromium and the remainder iron, such as -25 percent. Overlying the resistance coating is a thin film coating of a noble metal which may be platinum, rhodium, or iridium.
- a variable resistor of the trimrner type embodies the aforesaid resistive element within a suitable housing and employs a movable contact element of gold-palladium alloy consisting of about percent gold and 35 percent palladium, the remainder including silver, copper and platinum.
- a contact of carbon or carbon resin also is contemplated.
- the invention relates to a resistive element, and more particularly to a resistive element suitable for use in a variable resistor, and to a variable resistor using the resistive element.
- variable resistors such as trimmers
- the nickel-chromium-iron alloy is subject to oxidation, however, giving an objectionable noise characteristic.
- Attempts have been made to minimize noise by using platinum instead of the nickel-chromium-iron alloy, but this resulted in poor electrical properties.
- certain cermets have been tried, yielding non-uniform and poor results compared to the nickel-chromium-iron coating.
- variable resistors, particularly trimmers, designed for 500 to 20,000 ohms have continued to use the nickelchromium-iron alloy coating despite objectionable noise.
- An object of this invention is to provide a resistive element which eliminates the noise encountered with the conventional nickel-chromiurn-iron alloy coating while retaining the good electrical characteristics of this alloy.
- Another object is to provide a variable resistor including the resistive element of the invention and a movable contact element that cooperate to minimize objectionable noise.
- FIG. 1 is a plan view of a resistive element embodying the invention.
- FIG. 2 is a sectional view on line 2-2 of FIG. 1, the thickness of the coating portions exaggerated for clarity.
- FIG. 3 is an enlarged plan view, partly broken away, of an exemplary variable resistor embodying the invention.
- FIG. 4 is a sectional view on line 44 of FIG. 3.
- a typical resistive element embodying the invention includes a base 1 of insulating material. As shown, base 1 is a thin circular disk having a central opening 2 and a recess 3 in the periphery (FIG. 1).
- Base 1 has a double coating 5 on one surface adjacent the periphery, coating 5 consisting of a nickel-chromiumiron alloy coating 6 (FIG. 2) and an overlying thin film coating 7 of a noble metal which may be platinum, rhodium, or iridium.
- a nickel-chromiumiron alloy coating 6 (FIG. 2)
- a noble metal which may be platinum, rhodium, or iridium.
- double coating 5 extends to recess 3, and the coating ends are provided with metallic terminals 10 and 11 to which are connected conductors 12 and 13.
- conductors 12 and 13 are of gold.
- variable resistor of the trimmer type in FIGS. 3 and 4.
- the illustrated variable resistor includes a case 15 and an associated closure 16 made of suitable plastic insulating material such as diallyl phthalate.
- Case 15 has a hollow interior, and includes a central boss 17 having a reduced end portion 18 extending upwardly from the case bottom.
- a resistive element 20 of the type described above surrounds boss 17 and rests on a spacer 21 (FIG. 4). Element 20 is fixed against rotation.
- a circular gear 25 of insulating material having teeth 26 is mounted on reduced end portion 18 of boss 17, as best shown in FIG. 4.
- One edge portion of base 15 has a bore 27 that receives a screw 28 which is free to rotate within the bore.
- gear 25 rotates in response to adjustment of screw 28.
- a movable contact element 35 engages double coating 36 of resistive element 20, the element 35 having a portion 37 that engages gear 25 and rotates therewith.
- a terminal 38 (FIG. 4) associated with contact element 35 is connected to conductor 40.
- Conductors 41 and 42 are connected to the ends of double coating 36 as previously described with reference to the resistive element shown in FIGS. 1 and 2.
- compositions of the insulation material of base 1, the resistive coatings and the movable contact element 35 that characterize the invention now will be described.
- Base 1 may be any suitable insulating material, such as phenolic resins, epoxy resins and other insulating plastics, but preferably is a ceramic such as steatite, alumina, berylia, glass, quartz and the like. Ordinary soda glass preferably should be coated first with silicon dioxide, but borosilicate glass and other high temperature insulating glass are highly satisfactory without the silicon dioxide coating. Steatite and alumina are satisfactory and economical ceramic bases.
- suitable insulating material such as phenolic resins, epoxy resins and other insulating plastics, but preferably is a ceramic such as steatite, alumina, berylia, glass, quartz and the like.
- Ordinary soda glass preferably should be coated first with silicon dioxide, but borosilicate glass and other high temperature insulating glass are highly satisfactory without the silicon dioxide coating. Steatite and alumina are satisfactory and economical ceramic bases.
- the effective surface of insulating base 1 should be smooth so as to support and retain the thin double coating 5 without producing irregularities.
- the nickel-chromium-iron alloy for base coating 6 may range in composition by weight from 2-6-65 percent nickel, 15-75 percent chromium and the remainder iron, such as 5-25 percent.
- suitable alloys in percent by weight are 36 Ni48 Cr16 Fe; 30 Ni63 Cr-7 Fe; 20 Ni Cr5 Fe; and 60 Nil6 Cr-24 Fe.
- An alloy coating which has given particularly satisfactory results is 36 percent nickel, 48 percent chromium and 16 percent iron for resistive elements of 20,000 ohms. For elements of 500 ohms a highly satisfactory alloy is 20 percent nickel, 75 percent chromium and 5 percent iron.
- the ni-ckel-chorimium-iron alloy coating 6 may vary from one having a resistance of 500 ohms to 20,000 ohms with an actual thickness of 2,000 to Angstrom units (7.9- inches to 0.4 10 inches), which also may be expressed as 21.7 ohms per square to 870' ohms per square.
- Noble metal coating 7 may be platinum, rhodium, or iridium.
- the thickness of this coating is that of a thin film of less than 100 Angstrom units, the thickness being such that the coating has a resistance density of between 8,000 to 13,000 ohms per square. I have discovered that these metals in such thickness act as lubricants and allow the variable resistor to act without noise and with the good electrical properties of the nickel-chromium-iron coating beneath them.
- the noble metal coating wears off only very slowly when engaged by contact element 35. This is particularly so when contact element 35 is a gold-palladium alloy consisting essentially of no less than 10 percent gold and no less than 10 percent palladium, preferably about 10 percent gold and 35 percent palladium, the remainder including silver, copper and platinum. A carbon contact and also a carbon-tetrafluoroethylene resin contact also have been found highly satisfactory.
- the nickel-chromium-iron coating 6 and also the noble metal coating 7 are preferably applied by the well known vacuum deposition technique.
- Terminals 10 and 11 also may be a nickel-chromium vacuum deposition.
- Conductors 12 and 13 may be welded or otherwise secured thereto in conventional manner.
- the resistive element of the invention may be used as a fixed resistor, but is particularly useful combined with a movable contact element to produce a variable resistor of the type shown in FIGS. 3 and 4.
- Such variable resistors serve as trimmers in miniaturized test equipment, computers and the like. They have an extremely low temperature coefiicient (order of 50 p.p.m./ C. in the range 60 C. to +175 C.) and a substantially Zero noise level at trimmed position. Even during adjustment the noise level is negligible in most applications.
- a resistive element comprising an insulating base coated with an electrical resistance alloy consisting essentially of 20 to 65 percent nickel, 15 to 75 percent chromium and the remainder iron, having a film coating thereon of a noble metal selected from the group consisting of platinum, rhodium, and iridium, said nickel-chromiumiron coating having a thickness of between 100 and 2,000 Angstrom units, and said film coating having a thickness such that the resistance density thereof is between 8,000 and 13,000 ohms per square.
- a resistive element comprising an insulating base coated with an electrical resistance alloy consisting essentially of to 65 percent nickel, 15 to 75 percent chromium and the remainder iron, having a film coating thereon of a platinum metal, said film coating of platinum having a thickness of less than 100 Angstrom units.
- a resistive element comprising an insulating base coated with an electrical resistance alloy consisting essentially of 20 to percent nickel, 15 to percent chromium and the remainder iron, having a film coating thereon of a platinum metal, said nickel-chromium-iron coating having a thickness of between and 2,000 Anstrom units and said platinum film coating having a thickness such that the resistance density thereof is between 8,000 and 13,000 ohms per square.
- a resistive element comprising a steatite ceramic base coated with an alloy consisting essentially of approximately 20 to 65 percent nickel, 15 to 75 percent chromium, and the remainder iron, having a film coating of platinum on said nickel-chromium-iron coating, the thickness of said platinum coating being less than 100 Angstrom units and the thickness of the nickel-chromiumiron coating being between 100 and 2,000 Angstrom units.
- a variable resistor having a resistive element and a movable contact element engaging the surface of the resistive element
- the surface of the resistive element for engagement with said contact element is a film of a noble metal selected from the group consisting of platinum, rhodium, and iridium coated on a layer of an electrical resistance alloy consisting essentially of nickel, chromium and iron, said film coating being coextensive with said resistance alloy, and wherein the contact element consists essentially of a gold-palladium alloy.
- a variable resistor having a resistive element and a movable contact element engaging the surface of the resistive element
- the surface of the resistive element for engagement with said contact element is a film of a noble metal selected from the group consisting of platinum, rhodium, and iridium coated on a layer of an electrical resistance alloy consisting es sentially of nickel, chromium and iron, said film coating being coextensive with said resistance alloy, and wherein the contact element consists essentially of carbon.
Landscapes
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Non-Adjustable Resistors (AREA)
- Contacts (AREA)
- Apparatuses And Processes For Manufacturing Resistors (AREA)
- Adjustable Resistors (AREA)
Description
Nov. 14, 1967 v. D. ELARDE 3,353,134
RESISTIVE ELEMENT AND VARIABLE RESISTOR Filed Aug. 17, 1964 I I40 J; 20 2 35 7 In1/r2for" United States Patent O ABSTRACT OF THE DECLOSURE A resistive element has a circular base of insulating material provided with a central opening and a recess in the periphery. Adjacent the periphery the base has a thin resistance coating of a nickel-chromium-iron alloy ranging in composition by weight from 20-65 percent nickel, 15-75 percent chromium and the remainder iron, such as -25 percent. Overlying the resistance coating is a thin film coating of a noble metal which may be platinum, rhodium, or iridium. A variable resistor of the trimrner type embodies the aforesaid resistive element within a suitable housing and employs a movable contact element of gold-palladium alloy consisting of about percent gold and 35 percent palladium, the remainder including silver, copper and platinum. A contact of carbon or carbon resin also is contemplated.
The invention relates to a resistive element, and more particularly to a resistive element suitable for use in a variable resistor, and to a variable resistor using the resistive element.
Heretofore variable resistors such as trimmers, for example, have used as resistive elements a nickel-chromiumiron alloy coated on a base of insulating material. The nickel-chromium-iron alloy is subject to oxidation, however, giving an objectionable noise characteristic. Attempts have been made to minimize noise by using platinum instead of the nickel-chromium-iron alloy, but this resulted in poor electrical properties. Also, certain cermets have been tried, yielding non-uniform and poor results compared to the nickel-chromium-iron coating. Thus, variable resistors, particularly trimmers, designed for 500 to 20,000 ohms have continued to use the nickelchromium-iron alloy coating despite objectionable noise.
An object of this invention is to provide a resistive element which eliminates the noise encountered with the conventional nickel-chromiurn-iron alloy coating while retaining the good electrical characteristics of this alloy.
Another object is to provide a variable resistor including the resistive element of the invention and a movable contact element that cooperate to minimize objectionable noise.
Other objects, advantages and details of the invention will be apparent as the description proceeds, reference being had to the accompanying drawing wherein resistance devices embodying the invention are shown. It will be understood that the description and drawing are illustrative only, and that the scope of the invention is to be measured by the appended clahns.
In the drawing:
FIG. 1 is a plan view of a resistive element embodying the invention.
FIG. 2 is a sectional view on line 2-2 of FIG. 1, the thickness of the coating portions exaggerated for clarity.
FIG. 3 is an enlarged plan view, partly broken away, of an exemplary variable resistor embodying the invention.
FIG. 4 is a sectional view on line 44 of FIG. 3.
Referring to FIGS. 1 and 2 of the drawing, a typical resistive element embodying the invention includes a base 1 of insulating material. As shown, base 1 is a thin circular disk having a central opening 2 and a recess 3 in the periphery (FIG. 1).
Base 1 has a double coating 5 on one surface adjacent the periphery, coating 5 consisting of a nickel-chromiumiron alloy coating 6 (FIG. 2) and an overlying thin film coating 7 of a noble metal which may be platinum, rhodium, or iridium.
As shown in FIG. 1, double coating 5 extends to recess 3, and the coating ends are provided with metallic terminals 10 and 11 to which are connected conductors 12 and 13. In certain applications conductors 12 and 13 are of gold.
The resistive element of FIGS. 1 and 2 is shown embodied in a variable resistor of the trimmer type in FIGS. 3 and 4. Briefly, the illustrated variable resistor includes a case 15 and an associated closure 16 made of suitable plastic insulating material such as diallyl phthalate.
A circular gear 25 of insulating material having teeth 26 is mounted on reduced end portion 18 of boss 17, as best shown in FIG. 4. One edge portion of base 15 has a bore 27 that receives a screw 28 which is free to rotate within the bore. A pin 29 in case 15 engages screw 28 and restrains same against axial movement.
A movable contact element 35 engages double coating 36 of resistive element 20, the element 35 having a portion 37 that engages gear 25 and rotates therewith. A terminal 38 (FIG. 4) associated with contact element 35 is connected to conductor 40. Conductors 41 and 42 are connected to the ends of double coating 36 as previously described with reference to the resistive element shown in FIGS. 1 and 2.
The compositions of the insulation material of base 1, the resistive coatings and the movable contact element 35 that characterize the invention now will be described.
Base 1 may be any suitable insulating material, such as phenolic resins, epoxy resins and other insulating plastics, but preferably is a ceramic such as steatite, alumina, berylia, glass, quartz and the like. Ordinary soda glass preferably should be coated first with silicon dioxide, but borosilicate glass and other high temperature insulating glass are highly satisfactory without the silicon dioxide coating. Steatite and alumina are satisfactory and economical ceramic bases.
The effective surface of insulating base 1 should be smooth so as to support and retain the thin double coating 5 without producing irregularities.
The nickel-chromium-iron alloy for base coating 6 may range in composition by weight from 2-6-65 percent nickel, 15-75 percent chromium and the remainder iron, such as 5-25 percent. Examples of suitable alloys in percent by weight are 36 Ni48 Cr16 Fe; 30 Ni63 Cr-7 Fe; 20 Ni Cr5 Fe; and 60 Nil6 Cr-24 Fe. An alloy coating which has given particularly satisfactory results is 36 percent nickel, 48 percent chromium and 16 percent iron for resistive elements of 20,000 ohms. For elements of 500 ohms a highly satisfactory alloy is 20 percent nickel, 75 percent chromium and 5 percent iron.
The ni-ckel-chorimium-iron alloy coating 6 may vary from one having a resistance of 500 ohms to 20,000 ohms with an actual thickness of 2,000 to Angstrom units (7.9- inches to 0.4 10 inches), which also may be expressed as 21.7 ohms per square to 870' ohms per square.
The nickel-chromium-iron coating 6 and also the noble metal coating 7 are preferably applied by the well known vacuum deposition technique. Terminals 10 and 11 also may be a nickel-chromium vacuum deposition. Conductors 12 and 13 may be welded or otherwise secured thereto in conventional manner.
The resistive element of the invention may be used as a fixed resistor, but is particularly useful combined with a movable contact element to produce a variable resistor of the type shown in FIGS. 3 and 4. Such variable resistors serve as trimmers in miniaturized test equipment, computers and the like. They have an extremely low temperature coefiicient (order of 50 p.p.m./ C. in the range 60 C. to +175 C.) and a substantially Zero noise level at trimmed position. Even during adjustment the noise level is negligible in most applications.
From the above description it is thought that the construction and advantages of this invention will be readily apparent to those skilled in the art. Various changes in detail may be made without departing from the spirit or losing the advantages of the invention.
Having thus described the invention, what is claimed as new and desired to secure by Letters Patent is:
1. A resistive element comprising an insulating base coated with an electrical resistance alloy consisting essentially of 20 to 65 percent nickel, 15 to 75 percent chromium and the remainder iron, having a film coating thereon of a noble metal selected from the group consisting of platinum, rhodium, and iridium, said nickel-chromiumiron coating having a thickness of between 100 and 2,000 Angstrom units, and said film coating having a thickness such that the resistance density thereof is between 8,000 and 13,000 ohms per square.
2. A resistive element comprising an insulating base coated with an electrical resistance alloy consisting essentially of to 65 percent nickel, 15 to 75 percent chromium and the remainder iron, having a film coating thereon of a platinum metal, said film coating of platinum having a thickness of less than 100 Angstrom units.
3. A resistive element comprising an insulating base coated with an electrical resistance alloy consisting essentially of 20 to percent nickel, 15 to percent chromium and the remainder iron, having a film coating thereon of a platinum metal, said nickel-chromium-iron coating having a thickness of between and 2,000 Anstrom units and said platinum film coating having a thickness such that the resistance density thereof is between 8,000 and 13,000 ohms per square.
4. A resistive element comprising a steatite ceramic base coated with an alloy consisting essentially of approximately 20 to 65 percent nickel, 15 to 75 percent chromium, and the remainder iron, having a film coating of platinum on said nickel-chromium-iron coating, the thickness of said platinum coating being less than 100 Angstrom units and the thickness of the nickel-chromiumiron coating being between 100 and 2,000 Angstrom units.
5. In a variable resistor having a resistive element and a movable contact element engaging the surface of the resistive element, the improvement wherein the surface of the resistive element for engagement with said contact element is a film of a noble metal selected from the group consisting of platinum, rhodium, and iridium coated on a layer of an electrical resistance alloy consisting essentially of nickel, chromium and iron, said film coating being coextensive with said resistance alloy, and wherein the contact element consists essentially of a gold-palladium alloy.
6. In a variable resistor having a resistive element and a movable contact element engaging the surface of the resistive element, the improvement wherein the surface of the resistive element for engagement with said contact element is a film of a noble metal selected from the group consisting of platinum, rhodium, and iridium coated on a layer of an electrical resistance alloy consisting es sentially of nickel, chromium and iron, said film coating being coextensive with said resistance alloy, and wherein the contact element consists essentially of carbon.
References Cited UNITED STATES PATENTS 1,558,961 10/ 1925 Bullimore 29--195 2,366,614 1/ 1945 Hansell.
2,481,589 9/1949 Hansell 338-308 X 2,514,682 7/1950 Tellkamp 338163 2,705,830 4/1955 Lukens 29-195 2,912,663 11/1959 Van Alen 338-202 X 3,023,390 2/1962 Moratis et al 117217 3,165,714 1/1965 Dreyfus 3381 62 RICHARD M. WOOD, Primary Examiner.
I. G. SMITH, Assistant Examiner.
Claims (1)
1. A RESISTIVE ELEMENT COMPRISING AN INSULTATING BASE COATED WITH AN ELECTRICAL RESISTANCE ALLOY CONSISTING ESSENTIALLY OF 20 TO 65 PERCENT NICKEL, 15 TO 75 PERCENT CHROMIUM AND THE REMAINDER IRON, HAVING A FILM COATING THEREON OF A NOBLE METAL SELECTED FROM THE GROUP CONSISTING OF PLATINUM, RHODIUM, AND IRIDIUM, SAID NICKEL-CHROMIUMIRON COATING HAVING A THICKNESS OF BETWEEN 100 AND 2,000 ANGSTROM UNITS, AND SAID FILM COATING HAVING A THICKNESS SUCH THAT THE RESISTANCE DENSITY THEREOF IS BETWEEN 8,000 AND 13,000 OHMS PER SQUARE.
Priority Applications (9)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US389834A US3353134A (en) | 1964-08-17 | 1964-08-17 | Resistive element and variable resistor |
| IL24169A IL24169A (en) | 1964-08-17 | 1965-08-16 | Resistive element and variable resistor |
| SE10695/65A SE316224B (en) | 1964-08-17 | 1965-08-16 | |
| GB35061/65A GB1114052A (en) | 1964-08-17 | 1965-08-16 | Improvements in or relating to resistive elements for variable resistors |
| DK419165AA DK116605B (en) | 1964-08-17 | 1965-08-16 | Resistance element and variable resistor containing such an element. |
| DE1465205A DE1465205C3 (en) | 1964-08-17 | 1965-08-16 | Resistance element |
| CH1152065A CH424940A (en) | 1964-08-17 | 1965-08-17 | Electrical resistance |
| LU49329D LU49329A1 (en) | 1964-08-17 | 1965-08-17 | |
| FR28589A FR1513217A (en) | 1964-08-17 | 1965-08-17 | Resistant element and variable resistance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US389834A US3353134A (en) | 1964-08-17 | 1964-08-17 | Resistive element and variable resistor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US3353134A true US3353134A (en) | 1967-11-14 |
Family
ID=23539907
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US389834A Expired - Lifetime US3353134A (en) | 1964-08-17 | 1964-08-17 | Resistive element and variable resistor |
Country Status (9)
| Country | Link |
|---|---|
| US (1) | US3353134A (en) |
| CH (1) | CH424940A (en) |
| DE (1) | DE1465205C3 (en) |
| DK (1) | DK116605B (en) |
| FR (1) | FR1513217A (en) |
| GB (1) | GB1114052A (en) |
| IL (1) | IL24169A (en) |
| LU (1) | LU49329A1 (en) |
| SE (1) | SE316224B (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3629776A (en) * | 1967-10-24 | 1971-12-21 | Nippon Kogaku Kk | Sliding thin film resistance for measuring instruments |
| US3639878A (en) * | 1969-12-18 | 1972-02-01 | Dale Electronics | Adjustable potentiometer with contactor ratchet and central post-securing means for baseplate |
| US3673539A (en) * | 1970-05-11 | 1972-06-27 | Bunker Ramo | Electrical resistance element with a semiconductor overlay |
| US3717837A (en) * | 1965-06-04 | 1973-02-20 | Micro Electric Ag | Potentiometer |
| US4220944A (en) * | 1978-01-23 | 1980-09-02 | Vdo Adolf Schindling Ag | Resistance transducer with a non-linear characteristic curve |
| US4732802A (en) * | 1986-09-26 | 1988-03-22 | Bourns, Inc. | Cermet resistive element for variable resistor |
| US5038132A (en) * | 1989-12-22 | 1991-08-06 | Texas Instruments Incorporated | Dual function circuit board, a resistor element therefor, and a circuit embodying the element |
| WO2003028046A1 (en) * | 2001-09-04 | 2003-04-03 | Robert Bosch Gmbh | Potentiometer |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3322484A1 (en) * | 1983-06-22 | 1985-01-10 | Nitto Electric Industrial Co., Ltd., Ibaraki, Osaka | Resistance part of a sliding resistor |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1558961A (en) * | 1924-11-24 | 1925-10-27 | Bullimore William Richard | Manufacture of filaments or cathodes for electric lamps, thermionic tubes and the like |
| US2366614A (en) * | 1942-10-10 | 1945-01-02 | Rca Corp | Resistance having a low temperature coefficient |
| US2481589A (en) * | 1942-10-10 | 1949-09-13 | Rca Corp | Measuring of high-frequency power |
| US2514682A (en) * | 1948-04-09 | 1950-07-11 | Allen Bradley Co | Variable resistor apparatus |
| US2705830A (en) * | 1947-07-01 | 1955-04-12 | Hiram S Lukens | Coated metal objects |
| US2912663A (en) * | 1957-02-07 | 1959-11-10 | Borg George W Corp | Potentiometer |
| US3023390A (en) * | 1960-03-17 | 1962-02-27 | Westinghouse Electric Corp | Applying electrodes to ceramic members |
| US3165714A (en) * | 1961-09-04 | 1965-01-12 | Electronique & Automatisme Sa | Resistive layer track potentiometers |
-
1964
- 1964-08-17 US US389834A patent/US3353134A/en not_active Expired - Lifetime
-
1965
- 1965-08-16 IL IL24169A patent/IL24169A/en unknown
- 1965-08-16 SE SE10695/65A patent/SE316224B/xx unknown
- 1965-08-16 DK DK419165AA patent/DK116605B/en unknown
- 1965-08-16 DE DE1465205A patent/DE1465205C3/en not_active Expired
- 1965-08-16 GB GB35061/65A patent/GB1114052A/en not_active Expired
- 1965-08-17 FR FR28589A patent/FR1513217A/en not_active Expired
- 1965-08-17 CH CH1152065A patent/CH424940A/en unknown
- 1965-08-17 LU LU49329D patent/LU49329A1/xx unknown
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1558961A (en) * | 1924-11-24 | 1925-10-27 | Bullimore William Richard | Manufacture of filaments or cathodes for electric lamps, thermionic tubes and the like |
| US2366614A (en) * | 1942-10-10 | 1945-01-02 | Rca Corp | Resistance having a low temperature coefficient |
| US2481589A (en) * | 1942-10-10 | 1949-09-13 | Rca Corp | Measuring of high-frequency power |
| US2705830A (en) * | 1947-07-01 | 1955-04-12 | Hiram S Lukens | Coated metal objects |
| US2514682A (en) * | 1948-04-09 | 1950-07-11 | Allen Bradley Co | Variable resistor apparatus |
| US2912663A (en) * | 1957-02-07 | 1959-11-10 | Borg George W Corp | Potentiometer |
| US3023390A (en) * | 1960-03-17 | 1962-02-27 | Westinghouse Electric Corp | Applying electrodes to ceramic members |
| US3165714A (en) * | 1961-09-04 | 1965-01-12 | Electronique & Automatisme Sa | Resistive layer track potentiometers |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3717837A (en) * | 1965-06-04 | 1973-02-20 | Micro Electric Ag | Potentiometer |
| US3629776A (en) * | 1967-10-24 | 1971-12-21 | Nippon Kogaku Kk | Sliding thin film resistance for measuring instruments |
| US3639878A (en) * | 1969-12-18 | 1972-02-01 | Dale Electronics | Adjustable potentiometer with contactor ratchet and central post-securing means for baseplate |
| US3673539A (en) * | 1970-05-11 | 1972-06-27 | Bunker Ramo | Electrical resistance element with a semiconductor overlay |
| US4220944A (en) * | 1978-01-23 | 1980-09-02 | Vdo Adolf Schindling Ag | Resistance transducer with a non-linear characteristic curve |
| US4732802A (en) * | 1986-09-26 | 1988-03-22 | Bourns, Inc. | Cermet resistive element for variable resistor |
| US5038132A (en) * | 1989-12-22 | 1991-08-06 | Texas Instruments Incorporated | Dual function circuit board, a resistor element therefor, and a circuit embodying the element |
| WO2003028046A1 (en) * | 2001-09-04 | 2003-04-03 | Robert Bosch Gmbh | Potentiometer |
| US6838973B2 (en) | 2001-09-04 | 2005-01-04 | Robert Bosch Gmbh | Potentiometer |
Also Published As
| Publication number | Publication date |
|---|---|
| DE1465205C3 (en) | 1975-01-16 |
| SE316224B (en) | 1969-10-20 |
| GB1114052A (en) | 1968-05-15 |
| DE1465205A1 (en) | 1969-02-13 |
| IL24169A (en) | 1969-12-31 |
| DE1465205B2 (en) | 1972-09-21 |
| DK116605B (en) | 1970-01-26 |
| FR1513217A (en) | 1968-02-16 |
| LU49329A1 (en) | 1967-02-17 |
| CH424940A (en) | 1966-11-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US3134689A (en) | Thin film structure and method of making same | |
| US3353134A (en) | Resistive element and variable resistor | |
| US2962393A (en) | Method of preparing electrical resistors | |
| JPH0770366B2 (en) | Electric resistor | |
| US4276535A (en) | Thermistor | |
| US3379567A (en) | Tailored variable electrical resistance element | |
| US3393390A (en) | Potentiometer resistance device employing conductive plastic and a parallel resistance | |
| US2537733A (en) | Variable resistor | |
| US3673117A (en) | Electrical resistant material | |
| US4920635A (en) | A method of manufacturing a thermo-sensitive resistor | |
| US2711463A (en) | Tapped potentiometer element and associated network | |
| US3601744A (en) | Variable resistor with strain-reducing attachment means for the substrate | |
| DE1540167C3 (en) | Cermet resistance layer for a potentiometer | |
| US3232886A (en) | Resistor compositions | |
| US3165714A (en) | Resistive layer track potentiometers | |
| US2855493A (en) | Metal film resistor | |
| US2766359A (en) | Variable resistance device | |
| US3305817A (en) | Electric strain gauge having platinumpalladium-molybdenum alloy filament | |
| US3356982A (en) | Metal film resistor for low range and linear temperature coefficient | |
| US4517545A (en) | Thick film temperature sensitive device and method and material for making the same | |
| USRE18818E (en) | of new bocheixe | |
| US3248679A (en) | Metal alloy resistors | |
| US4774491A (en) | Metal film resistors | |
| US3061807A (en) | Contact isolated potentiometer | |
| US2978314A (en) | Compositions for electrical resistance films |