US4347528A
Expired / Lapsed
US
⏱️ 0.0 years remaining
G2 Set-up circuit for a television receiver
Assignee: Zenith Electronics LLC
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Filing: 1981-03-16
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Granted: 1982-08-31
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Expires: 2001-03-16
Abstract
Abstract A circuit is disclosed for establishing proper video output voltages in a color television receiver prior to setting the receiver's G2 voltage. In the preferred embodiment, the circuit includes three emitter follower stages, each coupled to the output of a video amplifier. The collectors of the emitter follower stages are coupled to a supply voltage through a common resistance. A two position switch is connected across the common resistance such that, during normal receiver operation, closure of the switch shunts the common resistance. When G2 set-up is to be effected, the switch is opened so that a predetermined voltage is dropped across the common resistance and the three emitter follower stages have similar, predetermined D.C. output voltages.
Inventors
- 👤 Fred D. Johnson
- 👤 George J. Tzakis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 00:01
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/64; H04N9/648
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
186 words
In a television receiver whose CRT includes three cathodes and a G2 electrode, and which has three video output amplifiers for driving the cathodes, a set-up circuit for establishing three similar video output voltages for use in properly setting the G2 electrode voltage, comprising: three video output transistors, each having an emitter, a collector and a base, and each receiving the output of one of the video amplifiers at its base; three emitter resistances, each coupled to the emitter of one of the video output transistors for developing a video output voltage thereacross; a common collector load; means for coupling the collector load between a supply voltage and the collectors of the three output transistors; and means for shunting the load during normal receiver operation to apply the supply voltage to the collectors of the output transistors, and for removing the shunt from the common load during G2 set-up so that the load is coupled in series with the collectors of all the output transistors for dropping a selected voltage thereacross and establishing a common, selected output voltage at the emitters of the video output transistors.
Claim 2
Dependent Claim
186 words
In a television receiver whose CRT includes three cathodes and a G2 electrode, and which has three video output amplifiers for driving the cathodes, a set-up circuit for establishing three similar video output voltages for use in properly setting the G2 electrode voltage, comprising: three video output transistors, each having an emitter, a collector and a base, and each receiving the output of one of the video amplifiers at its base; three emitter resistances, each coupled to the emitter of one of the video output transistors for developing a video output voltage thereacross; a common collector load; means for coupling the collector load between a supply voltage and the collectors of the three output transistors; and means for shunting the load during normal receiver operation to apply the supply voltage to the collectors of the output transistors, and for removing the shunt from the common load during G2 set-up so that the load is coupled in series with the collectors of all the output transistors for dropping a selected voltage thereacross and establishing a common, selected output voltage at the emitters of the video output transistors.
Claim 3
Dependent Claim
33 words
A set-up circuit as set forth in claim 1 wherein each of the emitter resistances is coupled between the emitter of a video output transistor and the input of its associated video amplifier.
Claim 4
Dependent Claim
26 words
A set-up circuit as set forth in claim 1 wherein said shunting means includes a two position switch connected in parallel with the common collector load.
Claim 5
Dependent Claim
40 words
A set-up circuit as set forth in claim 3 wherein the common collector load constitutes a resistor whose value is selected to establish a predetermined D.C. output voltage at the emitters of the output transistors when the switch is open.
References Cited (Backward Citations)
US3670095A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-08-30 | 1986-03-01 | 1986-08-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-08-30 | 1990-03-01 | 1990-08-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-08-30 | 1994-03-01 | 1994-08-31 | $7700.00 | Window Closed / Lapsed |