US3742377A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Differential amplifier with means for balancing out offset terms
Assignee: National Semiconductor Corp
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Filing: 1971-07-08
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Granted: 1973-06-26
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Expires: 1991-07-08
Abstract
Abstract A differential amplifier comprising a first amplifying circuit including a dual emitter transistor, a second amplifying circuit in parallel with the first amplifying circuit and having a second dual emitter transistor with one of its emitters coupled to one of the emitters of the first transistor and a potentiometer having a resistance element with one end coupled to the other emitter of the first transistor and its other end coupled to the other emitter of the second transistor and its wiper contact coupled to the commonly coupled emitters whereby the collector currents of the first and second transistors can be selectively adjusted by adjusting the potentiometer of the wiper contact relative to the resistance element.
Inventors
- 👤 R Dobkin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 03:53
CPC Classifications
G; G06; G06G; G06G7/00; G06G7/12; G06G7/14; H; H03; H03F; H03F1/00; H03F1/30; H03F1/306; H03F3/00; H03F3/30; H03F3/3001; H03F3/34; H03F3/343; H03F3/347; H03F3/45; H03F3/45071; H03F3/45076; H03F3/45479; H03G; H03G1/00; H03G1/0005; H03G1/0017; H03G1/0023; H03G3/00; H03G3/02; H03G3/04; H03G3/10; H03F2203/00; H03F2203/45; H03F2203/45031; H03F2203/45188
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
185 words
A differential amplifier, comprising: a first amplifying circuit including a first load impedance and a first transistor having a first base for receiving a first input signal, a first collector coupled to said first load impedance, a first emitter, and a second emitter; a second amplifying circuit including a second load impedance and a second transistor having a second base for receiving a second input signal, a second collector coupled to said second load impedance, a third emitter coupled to said first emitter, and a fourth emitter; means for coupling said first and second load impedances to a first potential source, a current source coupled to said first emitter and said third emitter, means for coupling said current source to a second potential source, and a potentiometer including a resistance element having one end coupled to said second emitter and the opposite end coupled to said fourth emitter, and a movable wiper contact coupled to said first and third emitters, whereby the collector currents of said first and second transistors can be varied by adjusting the position at which said wiper contacts said resistance element.
Claim 2
Dependent Claim
185 words
A differential amplifier, comprising: a first amplifying circuit including a first load impedance and a first transistor having a first base for receiving a first input signal, a first collector coupled to said first load impedance, a first emitter, and a second emitter; a second amplifying circuit including a second load impedance and a second transistor having a second base for receiving a second input signal, a second collector coupled to said second load impedance, a third emitter coupled to said first emitter, and a fourth emitter; means for coupling said first and second load impedances to a first potential source, a current source coupled to said first emitter and said third emitter, means for coupling said current source to a second potential source, and a potentiometer including a resistance element having one end coupled to said second emitter and the opposite end coupled to said fourth emitter, and a movable wiper contact coupled to said first and third emitters, whereby the collector currents of said first and second transistors can be varied by adjusting the position at which said wiper contacts said resistance element.
Claim 3
Dependent Claim
221 words
A differential amplifIer, comprising: a first transistor having a first base for receiving a first input signal, a first collector, and a first emitter; a second transistor having a second base for receiving a second input signal, a second collector, and a second emitter coupled to said first emitter; a third transistor having a third collector coupled to said first collector, a third emitter, and a fourth emitter; a fourth transistor having a fourth collector coupled to said second collector, a fifth emitter coupled to said third emitter, and a sixth emitter; said third transistor having a third base coupled to said third collector, and said fourth transistor having a fourth base coupled to said fourth collector, whereby said third and fourth transistors provide active load impedances for said differential amplifier, means for coupling a first source of potential to said third and fifth emitters, a current source coupling said first and second emitters to a second source of potential, and a potentiometer including a resistance element having one end coupled to said fourth emitter, the opposite end coupled to said sixth emitter, and a wiper contact coupled to said third and fifth emitters, whereby an output signal taken across said first and second collectors can be adjusted by changing the contact position of said wiper contact on said resistance element.
Claim 4
Dependent Claim
221 words
A differential amplifIer, comprising: a first transistor having a first base for receiving a first input signal, a first collector, and a first emitter; a second transistor having a second base for receiving a second input signal, a second collector, and a second emitter coupled to said first emitter; a third transistor having a third collector coupled to said first collector, a third emitter, and a fourth emitter; a fourth transistor having a fourth collector coupled to said second collector, a fifth emitter coupled to said third emitter, and a sixth emitter; said third transistor having a third base coupled to said third collector, and said fourth transistor having a fourth base coupled to said fourth collector, whereby said third and fourth transistors provide active load impedances for said differential amplifier, means for coupling a first source of potential to said third and fifth emitters, a current source coupling said first and second emitters to a second source of potential, and a potentiometer including a resistance element having one end coupled to said fourth emitter, the opposite end coupled to said sixth emitter, and a wiper contact coupled to said third and fifth emitters, whereby an output signal taken across said first and second collectors can be adjusted by changing the contact position of said wiper contact on said resistance element.
Claim 5
Dependent Claim
36 words
A differential amplifier as recited in claim 2 and further comprising a first resistive impedance coupling said first collector to said third collector, and a second resistive impedance coupling said second collector to said fourth collector.
Claim 6
Dependent Claim
196 words
A differential amplifier, comprising; a first transistor having a first base for receiving a first input signal, a first collector, and a first emitter; a second transistor having a second base for receiving a second input signal, a second collector, and a second emitter coupled to said first emitter; a third transistor having a third collector coupled to said first collector, a third base coupled to said third collector, a third emitter, and a fourth emitter; a fourth transistor having a fourth collector coupled to said second collector, a fourth base coupled to said third base, a fifth emitter coupled to said third emitter, and a sixth emitter; means for coupling a first source of potential to said third and fifth emitters, a potentiometer including a resistance element having one end coupled to said fourth emitter, the opposite end coupled to said sixth emitter, and a wiper contact coupled to said third and fifth emitters, whereby an output current taken at said second collector can be adjusted by changing the contact position of said wiper contact on said resistance element, and a current source coupling said first and second emitters to a second source of potential.
Claim 7
Dependent Claim
196 words
A differential amplifier, comprising; a first transistor having a first base for receiving a first input signal, a first collector, and a first emitter; a second transistor having a second base for receiving a second input signal, a second collector, and a second emitter coupled to said first emitter; a third transistor having a third collector coupled to said first collector, a third base coupled to said third collector, a third emitter, and a fourth emitter; a fourth transistor having a fourth collector coupled to said second collector, a fourth base coupled to said third base, a fifth emitter coupled to said third emitter, and a sixth emitter; means for coupling a first source of potential to said third and fifth emitters, a potentiometer including a resistance element having one end coupled to said fourth emitter, the opposite end coupled to said sixth emitter, and a wiper contact coupled to said third and fifth emitters, whereby an output current taken at said second collector can be adjusted by changing the contact position of said wiper contact on said resistance element, and a current source coupling said first and second emitters to a second source of potential.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-06-25 | 1976-12-25 | 1977-06-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-25 | 1980-12-25 | 1981-06-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-25 | 1984-12-25 | 1985-06-26 | $7700.00 | Window Closed / Lapsed |