US3781699A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Differential amplifier circuit
Assignee: Hitachi Ltd
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Filing: 1972-09-27
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Granted: 1973-12-25
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Expires: 1992-09-27
Abstract
Abstract A differential amplifier circuit which comprises an emitter follower transistor adapted to operate at the same time the power supply is turned on, the output of said transistor being fed to the first input of the differential amplifier and servicing to charge a capacitor connected to the second input of said differential amplifier, whereby the rise of the output signal is made quick and the so-called pop signal normally produced in the amplifier is eliminated.
Inventors
- 👤 Y Sakamoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:42
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/45; H03F3/45071; H03F1/00; H03F1/30; H03F1/305; H03G; H03G11/00; H03G11/08
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
135 words
A differential amplifier circuit comprising a differential amplifier having first and second inputs and an output, a first capacitor connected between said first input and an input terminal, a feedback path including a second capacitor connected between said second input and one terminal of a power supply, a feedback element connected between said differential amplifier output and said second input thereof for feeding-back an output of said differential amplifier to said second input, voltage divider means including an emitter follower transistor for dividing the voltage across terminals of said power supply and providing a voltage to be applied to said first input, a first resistor connected between an emitter of said emitter follower transistor and said first input, and a second resistor connected between said emitter of said emitter follower transistor and said second capacitor.
Claim 2
Dependent Claim
135 words
A differential amplifier circuit comprising a differential amplifier having first and second inputs and an output, a first capacitor connected between said first input and an input terminal, a feedback path including a second capacitor connected between said second input and one terminal of a power supply, a feedback element connected between said differential amplifier output and said second input thereof for feeding-back an output of said differential amplifier to said second input, voltage divider means including an emitter follower transistor for dividing the voltage across terminals of said power supply and providing a voltage to be applied to said first input, a first resistor connected between an emitter of said emitter follower transistor and said first input, and a second resistor connected between said emitter of said emitter follower transistor and said second capacitor.
Claim 3
Dependent Claim
52 words
A differential amplifier circuit according to claim 1 wherein R1 is the resistance of said first resistor, R2 is the resistance of said second resistor, C1 is the capacity of said first capacitor and C2 is the capacity of the second capacitor, the elements having the relation C1.R1 > or = C2.R2.
Claim 4
Dependent Claim
34 words
A differential amplifier circuit according to claim 1 wherein a capacitor serving as a ripple filter is connected between said emitter of said emitter follower transistor and said one terminal of said power supply.
Claim 5
Dependent Claim
52 words
A differential amplifier circuit according to claim 3, wherein R1 is the resistance of said first resistor, R2 is the resistance of said second resistor, C1 is the capacity of said first capacitor and C2 is the capacity of said second capacitor, the elements having the relation C1.R1 > or = C2.R2.
References Cited (Backward Citations)
US3721914A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-12-24 | 1977-06-25 | 1977-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-24 | 1981-06-25 | 1981-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-24 | 1985-06-25 | 1985-12-25 | $7700.00 | Window Closed / Lapsed |