US3649944A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Film-type power resistor
Assignee: Individual
•
Filing: 1970-05-25
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Granted: 1972-03-14
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Expires: 1990-05-25
Abstract
Abstract A film-type power resistor consists of a ceramic wafer or washer having a central opening, one side of such washer being printed at its outer and inner edges with generally annular traces of termination metal. An electrically resistive film is printed on such one side over all portions of, and between, the termination metal, excepting for predetermined adjacent end portions which are connected to radially outwardly extending terminal lugs or leads. In one embodiment, the metal traces are continuous, whereas in another embodiment they are interrupted in order to create series-related resistor portions. The washer (and its associated films) are mounted over a metal base and are embedded in a thermosetting synthetic resin, the base having an upwardly extending central post which passes through the opening in the washer to the upper surface of the resin. In accordance with the method, the planar surface of a ceramic substrate is first printed with termination film traces, following which such traces are overprinted with electrically resistive film. The ceramic (with its associated coatings) is then fired in order to cure the resistive film. Thereafter, the entire outer surface of the resistive film is uniformly abraded by means of a jet of abrasive particles, the abrading continuing in a uniform manner until the resistive film is within the required tolerance. During the abrading step, the terminal regions of the terminal film traces are masked. Thereafter, terminal lugs or leads are connected to such terminal regions.
Inventors
- 👤 Richard E Caddock
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 10:07
CPC Classifications
H; H01; H01C; H01C17/00; H01C17/22; H01C17/24; H01C17/245; H01C7/00
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
39 words
The invention as claimed in claim 1, in which first and second terminal conductors are connected, respectively, to said terminal ends of said outer and inner traces and extended outwardly from the resistor for connection in an electrical circuit.
Claim 2
Dependent Claim
77 words
The invention as claimed in claim 1, in which said outer trace is continuous between said terminal end thereof and another end also disposed on said one side of said opening, and in which said inner trace is continuous between said terminal end thereof and another end also disposed on said one side of said opening, whereby a single low-resistance resistor is formed by said resistive film between said terminal ends of said inner and outer traces.
Claim 3
Dependent Claim
131 words
The invention as claimed in claim 1, in which said outer trace is interrupted at at least one point between said terminal end thereof and the other end thereof, said other end of said outer trace being disposed on said one side of said opening, in which said inner trace is interrupted at at least one point between said terminal end thereof and the other end thereof, said other end of said inner trace being disposed on said one side of said opening, and in which portions of said resistive film are interrupted at the trace interruptions and also at the adjacent regions between said inner and outer traces, said interruptions being such that at least three series-related radial-flow film-type resistors are formed by said resistive film between said terminal ends.
Claim 4
Dependent Claim
103 words
The invention as claimed in claim 1, in which at least one of said inner and outer traces is interrupted at a region between said terminal end thereof and the other end thereof, said other end thereof being disposed on said one side of said opening, and in which said resistive film is correspondingly interrupted at the trace interruption and also at the adjacent region between said inner and outer traces, said interruptions being such that at least two film-type radial-flow resistors are provided by said resistive film between said traces and in series-circuit relationship relative to each other between said terminal ends.
Claim 5
Dependent Claim
57 words
The invention as claimed in claim 5, in which the connection between said two series-related resistors is formed by the other of said inner and outer traces, said other trace being overprinted with said resistiVe film, whereby current flow between said series-related resistors is through the parallel combination of said other trace and the resistive overprint thereon.
Claim 6
Dependent Claim
50 words
The invention as claimed in claim 1, in which said wafer has concentric inner and outer edges each of which is circular, said inner edge defining said opening in said wafer, and in which said inner and outer traces are parallel to and respectively adjacent said inner and outer edges.
Claim 7
Dependent Claim
29 words
The invention as claimed in claim 1, in which said resistive film is overprinted over said traces at all portions of said traces except at said terminal ends thereof.
Claim 8
Dependent Claim
102 words
The invention as claimed in claim 1, in which said wafer is formed of ceramic, said traces are metal films, and said resistive film is a complex metal oxide in a glass matrix. 10 The invention as claimed in claim 1, in which first and second terminal conductors are connected, respectively, to said terminal ends of said outer and inner traces and extend outwardly form the resistor for connection in an electrical circuit, and in which said terminal conductors are first and second terminal lugs secured, respectively, to said terminal ends and lying generally in the same plane as said resistive film.
Claim 9
Dependent Claim
81 words
The invention as claimed in claim 1, in which the lower surface of the wafer is planar and is mounted in flatwise engagement with the planar upper surface of a metal base having a central opening therein corresponding to said opening in said wafer, and in which a mass of thermosetting synthetic resin is provided over said wafer to embed the same and provide environmental protection, said mass of resin having an opening therein over said central opening in said base.
Claim 10
Dependent Claim
66 words
The invention as claimed in claim 11, in which said metal base has an upwardly extending central post which extends through said opening in said wafer and through said opening in said resin, said post being embedded in said resin except at the upper end of said post, said post having an opening therethrough registered with said base opening and adapted to receive a mounting bolt.
Claim 11
Dependent Claim
154 words
The invention as claimed in claim 1, in which the lower surface of said wafer is planar and is mounted in flatwise engagement with the planar upper surface of a metal base having a central opening therein corresponding to said opening in said wafer, in which radially outwardly extending terminal conductors are connected, respectively, to said terminal ends of said traces, in which a mass of thermosetting synthetic resin is molded over said wafer and over the inner portions of said terminal conductors to embed the same and provide environmental protection, in which said outer trace is continuous between said terminal end thereof and another end also disposed on said one side of said opening, and in which said inner trace is continuous between said terminal end thereof and another end also disposed on said one side of said opening, whereby a single low-resistance resistor is provided by said film between said terminal conductors.
Claim 12
Dependent Claim
210 words
The invention as claimed in claim 1, in which the lower surface of said wafer is planar and is mounted in flatwise engagement with the planar upper surface of a metal base having a central opening therein corresponding to said opening in said wafer, in which radially outwardly extending terminal conductors are connected, respectively, to said terminal ends of said traces, in which a mass of thermosetting synthetic resin is molded over said wafer and over the inner portions of said terminal conductors to embed the same and provide environmental protection, in which said outer trace is interrupted at at least one point between said terminal end and the other end thereof, said other end being disposed on said one side of said opening, in which said inner trace is interrupted at at least one point between said terminal end thereof and the other end thereof, said other end of said inner trace being disposed on said one side of said opening, and in which portions of said resistiVe film are interrupted at the trace interruptions and also at the adjacent regions between said inner and outer traces, said interruptions being such that at least three series-related radial-flow film-type resistors are formed by said resistive film between said terminal conductors.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-03-14 | 1975-09-13 | 1976-03-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-14 | 1979-09-13 | 1980-03-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-14 | 1983-09-13 | 1984-03-14 | $7700.00 | Window Closed / Lapsed |