US4024427A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Degaussing circuit
Assignee: US Philips Corp
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Filing: 1975-11-20
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Granted: 1977-05-17
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Expires: 1995-11-20
Abstract
Abstract A degaussing circuit, for example for a color television receiver, in which the degaussing coil is in series with a PTC-thermistor and in which the series arrangement thus formed is in parallel across a second PTC thermistor and across an a.c. voltage source, for example the supply mains. The thermistors are thermically coupled.
Inventors
- 👤 Charles Belhomme
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 01:14
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/02; H01C7/022; H01F; H01F13/00; H04; H04N; H04N9/00; H04N9/12; H04N9/16; H04N9/29
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
130 words
A degaussing circuit comprising the series arrangement of a degaussing coil and a first thermistor having a positive temperature coefficient, only a second thermistor having a positive temperature coefficient thermically coupled to the first thermistor and electrically parallel coupled to said series arrangement, both of said thermistors having different Curie points, means for applying an alternating current voltage to said thermistors, said voltage being substantially the same a substantial time after said application, the resistance value of the second thermistor at a higher temperature than the highest of the Curie points being lower than the resistance value of the first thermistor at the same temperature, and the resistance value of the second thermistor before said alternating current voltage is applied being higher than the resistance value of the first thermistor.
Claim 2
Dependent Claim
130 words
A degaussing circuit comprising the series arrangement of a degaussing coil and a first thermistor having a positive temperature coefficient, only a second thermistor having a positive temperature coefficient thermically coupled to the first thermistor and electrically parallel coupled to said series arrangement, both of said thermistors having different Curie points, means for applying an alternating current voltage to said thermistors, said voltage being substantially the same a substantial time after said application, the resistance value of the second thermistor at a higher temperature than the highest of the Curie points being lower than the resistance value of the first thermistor at the same temperature, and the resistance value of the second thermistor before said alternating current voltage is applied being higher than the resistance value of the first thermistor.
Claim 3
Dependent Claim
23 words
A circuit as claimed in claim 1, wherein the Curie point of the second thermistor exceeds the Curie point of the first thermistor.
Claim 4
Dependent Claim
23 words
A colour television receiver comprising, a picture display tube of the shadow mask type and a degaussing circuit as claimed in claim 1.
Claim 5
Dependent Claim
86 words
A composite thermistor element for use in a degaussing circuit, comprising first and second thermically coupled thermistors, each having a positive temperature coefficient, both of said thermistors having different Curie points, the resistance value of the second thermistor at a higher temperature than the highest of the Curie points being lower than the resistance value of the first thermistor at the same temperature, the resistance value of the second thermistor before said alternating current is applied being higher than the resistance value of the first thermistor.
Claim 6
Dependent Claim
86 words
A composite thermistor element for use in a degaussing circuit, comprising first and second thermically coupled thermistors, each having a positive temperature coefficient, both of said thermistors having different Curie points, the resistance value of the second thermistor at a higher temperature than the highest of the Curie points being lower than the resistance value of the first thermistor at the same temperature, the resistance value of the second thermistor before said alternating current is applied being higher than the resistance value of the first thermistor.
Claim 7
Dependent Claim
24 words
A thermistor element as claimed in claim 4, wherein the Curie point of the second thermistor exceeds the Curie point of the first thermistor.
Claim 8
Dependent Claim
35 words
A thermistor element as claimed in claim 5, wherein the molecule of the material from which the second thermistor consists contains more lead than the molecule of the material from which the first thermistor consists.
Claim 9
Dependent Claim
35 words
A thermistor element as claimed in claim 5, wherein the molecule of the material of which the first thermistor comprises contains more strontium than the molecule of the material of which the second thermistor comprises.
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) | 1980-05-16 | 1980-11-15 | 1981-05-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-16 | 1984-11-15 | 1985-05-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-16 | 1988-11-15 | 1989-05-17 | $7700.00 | Window Closed / Lapsed |