US4390820A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Television receiver ferroresonant load power supply disabling circuit
Assignee: RCA Corp
•
Filing: 1981-09-03
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Granted: 1983-06-28
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Expires: 2001-09-03
Abstract
Abstract The primary winding of a high leakage transformer is coupled to a source of alternating input voltage for developing an alternating supply voltage across a secondary winding of the transformer. A self-regulating, ferroresonant load circuit includes a saturable reactor that has a first winding coupled to the transformer secondary winding for regulating the supply voltage. A high voltage winding of the transformer steps up the supply voltage. The stepped up voltage is rectified to produce an ultor accelerating potential for a color picture tube of a television receiver. If the saturable reactor first winding is disconnected from the transformer secondary winding, the supply voltage and ultor accelerating potential undesirably tend to increase in amplitude. To protect against the emission of excessive X-radiation from the phosphor screen of the picture tube in such an event, the heater filaments of the picture tube cathode electrodes are energized by a second winding of the saturable reactor. If the saturable reactor first winding becomes disconnected, heater energization is removed, producing a blank picture screen.
Inventors
- 👤 Donald H. Willis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 10:05
CPC Classifications
H; H04; H04N; H04N3/00; H04N3/10; H04N3/16; H04N3/20
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
158 words
A disabling circuit for a television display system, comprising: a source of input voltage; a transformer including primary and secondary windings; said primary winding being coupled to said source for developing an alternating supply voltage across said secondary winding; a self-regulating load circuit including a saturable reactor having a first winding coupled to said transformer secondary winding for regulating said supply voltage; a tertiary winding of said transformer for stepping up said regulated supply voltage; a high voltage circuit coupled to said tertiary winding for developing an ultor accelerating potential for a picture tube of said television display system; a load circuit within said television display system; and means coupled to said television display system load circuit and to said saturable reactor first winding for energizing said television display system load circuit such that the disconnection of said saturable reactor first winding from said transformer secondary winding disables the normal energization of said television display system load circuit.
Claim 2
Dependent Claim
158 words
A disabling circuit for a television display system, comprising: a source of input voltage; a transformer including primary and secondary windings; said primary winding being coupled to said source for developing an alternating supply voltage across said secondary winding; a self-regulating load circuit including a saturable reactor having a first winding coupled to said transformer secondary winding for regulating said supply voltage; a tertiary winding of said transformer for stepping up said regulated supply voltage; a high voltage circuit coupled to said tertiary winding for developing an ultor accelerating potential for a picture tube of said television display system; a load circuit within said television display system; and means coupled to said television display system load circuit and to said saturable reactor first winding for energizing said television display system load circuit such that the disconnection of said saturable reactor first winding from said transformer secondary winding disables the normal energization of said television display system load circuit.
Claim 3
Dependent Claim
19 words
A disabling circuit according to claim 1 wherein said energizing means comprises a second winding of said saturable reactor.
Claim 4
Dependent Claim
24 words
A disabling circuit according to claims 1 or 2 wherein said television display system load circuit comprises a heater filament of said picture tube.
Claim 5
Dependent Claim
29 words
A disabling circuit according to claim 1 wherein said supply voltage tends to increase in amplitude when said saturable reactor first winding is disconnected from said transformer secondary winding.
Claim 6
Dependent Claim
19 words
A disabling circuit according to claim 4 wherein substantial leakage inductance exists between said transformer primary and secondary windings.
Claim 7
Dependent Claim
22 words
A disabling circuit according to claim 5 wherein said television display system load circuit comprises a heater filament of said picture tube.
Claim 8
Dependent Claim
19 words
A disabling circuit according to claim 6 wherein said energizing means comprises a second winding of said saturable reactor.
Claim 9
Dependent Claim
57 words
A disabling circuit according to claim 7 wherein said transformer includes a fourth winding magnetically tightly coupled to said transformer primary winding and wherein said self-regulating load circuit includes a capacitance coupled between two terminals of said transformer secondary winding and coupled across the series arrangement of said saturable reactor first winding and said transformer fourth winding.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-06-27 | 1986-12-27 | 1987-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-06-27 | 1990-12-27 | 1991-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-06-27 | 1994-12-27 | 1995-06-28 | $7700.00 | Window Closed / Lapsed |