Patent US3707670A successfully refreshed from Google Patents.
US3707670A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable low resistance circuit with superconducting shunts
Assignee: Keithley Instruments LLC
•
Filing: 1969-04-01
•
Granted: 1972-12-26
•
Expires: 1989-04-01
Abstract
Abstract Low resistance circuit, for use in series with superconducting component, having resistance value changeable between a low resistance and that of a superconductor below its critical temperature Tc. A superconducting switch is rendered nonsuperconducting by heating, while in a cryogenic environment, with an electric resistor.
Inventors
- 👤 Robert J Erdman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 17:11
CPC Classifications
H; H03; H03H; H03H7/00; H03H7/24; H03K; H03K17/00; H03K17/51; H03K17/92; Y; Y10; Y10S; Y10S505/00; Y10S505/825; Y10S505/856; Y10S505/857; Y10S505/86
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
136 words
A circuit having a portion whose resistance value is changeable between that of a superconductor to a small resistance value comprising a first resistor, said first resistor having a small resistance value, superconducting wires for connecting said resistor into the circuit, and additional superconducting wire connected across said resistor to short circuit the same, and heating means for selectively heating said additional superconducting wire while disposed in a cryogenic environment for cooling the wire below its critical temperature TC to heat the additional wire above its critical temperature TC whereby said portion of said circuit has the small resistance value of said first resistor when said heating means has heated said additional superconducting wire above its critical temperature and said portion of said circuit is superconductive when said additional superconducting wire is below its critical temperature.
Claim 2
Dependent Claim
136 words
A circuit having a portion whose resistance value is changeable between that of a superconductor to a small resistance value comprising a first resistor, said first resistor having a small resistance value, superconducting wires for connecting said resistor into the circuit, and additional superconducting wire connected across said resistor to short circuit the same, and heating means for selectively heating said additional superconducting wire while disposed in a cryogenic environment for cooling the wire below its critical temperature TC to heat the additional wire above its critical temperature TC whereby said portion of said circuit has the small resistance value of said first resistor when said heating means has heated said additional superconducting wire above its critical temperature and said portion of said circuit is superconductive when said additional superconducting wire is below its critical temperature.
Claim 3
Dependent Claim
35 words
A circuit as defined in claim 1 wherein said heating means comprises an electrical resistance element mounted in juxtaposition to said additional superconducting wire and means for selectively establishing a current flow in said element.
Claim 4
Dependent Claim
27 words
A circuit as defined in claim 2 wherein said circuit further comprises a second resistor, and superconductors connecting said second resistor in series with said first resistor.
Claim 5
Independent Claim
66 words
The method of changing the magnitude of the electrical resistance in series in a superconducting circuit which includes at least one cryogenic resistor in the circuit comprising cooling the circuit to superconducting temperatures to establish superconduction in the circuit, shunting the cryogenic resistor in the circuit with the superconductor, and selectively heating or cooling the shunting superconductor to effectively render the latter superconducting or non-superconducting selectively.
Claim 6
Independent Claim
66 words
The method of changing the magnitude of the electrical resistance in series in a superconducting circuit which includes at least one cryogenic resistor in the circuit comprising cooling the circuit to superconducting temperatures to establish superconduction in the circuit, shunting the cryogenic resistor in the circuit with the superconductor, and selectively heating or cooling the shunting superconductor to effectively render the latter superconducting or non-superconducting selectively.
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) | 1975-12-26 | 1976-06-26 | 1976-12-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-12-26 | 1980-06-26 | 1980-12-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-12-26 | 1984-06-26 | 1984-12-26 | $7700.00 | Window Closed / Lapsed |