US3868581A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Current amplifier
Assignee: RCA Corp
•
Filing: 1973-07-20
•
Granted: 1975-02-25
•
Expires: 1993-07-20
Abstract
Abstract A first grounded-emitter amplifier transistor is followed in direct coupled cascade by a second grounded-emitter amplifier transistor. The first grounded-emitter transistor has directcoupled collector-to-base negative feedback to regulate its collector current to be proportional to applied input current. The direct-coupled feedback includes means to regulate the collector-to-base potential of said first transistor to be proportional to the logarithm of the applied input current. The collector current of the second transistor is thereby in fixed proportion to the applied input current and independent of the forward current gain of the transistors.
Inventors
- 👤 Adel Abdel Aziz Ahmed
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 02:25
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/42; G; G05; G05F; G05F3/00; G05F3/02; G05F3/08; G05F3/10; G05F3/16; G05F3/20; G05F3/26; G05F3/265
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
147 words
A current amplifier comprising: an input, a common and an output terminal; first and second transistors operated at substantially the same absolute temperature T, each having an emitter electrode connected to said common terminal and each having a base and a collector electrode, each having a base-emitter junction between its base and emitter electrodes, said first transistor collector electrode being direct current conductively coupled to said input terminal and directly connected to said second transistor base electrode; means for coupling said second transistor collector electrode to said output terminal, and a direct-coupled collector-to-base degenerative feedback connection of said first transistor consisting of means responsive to the absolute temperature T to provide between a first and a second of its terminals a potential proportional to T, said first and said second terminals being respectively connected to said first transistor collector electrode and to said first transistor base electrode.
Claim 2
Dependent Claim
147 words
A current amplifier comprising: an input, a common and an output terminal; first and second transistors operated at substantially the same absolute temperature T, each having an emitter electrode connected to said common terminal and each having a base and a collector electrode, each having a base-emitter junction between its base and emitter electrodes, said first transistor collector electrode being direct current conductively coupled to said input terminal and directly connected to said second transistor base electrode; means for coupling said second transistor collector electrode to said output terminal, and a direct-coupled collector-to-base degenerative feedback connection of said first transistor consisting of means responsive to the absolute temperature T to provide between a first and a second of its terminals a potential proportional to T, said first and said second terminals being respectively connected to said first transistor collector electrode and to said first transistor base electrode.
Claim 3
Dependent Claim
113 words
A current amplifier as claimed in claim 1 wherein said direct-coupled collector-to-base degenerative feedback connection comprises: a number 2N+1 of diodes each operated at an absolute temperature substantially equal to T, N being a positive integer, the first of which diodes is connected between the base and the emitter electrodes of said first transistor to parallel its base-emitter junction, a first half of the remainder coupled between said input terminal and said first transistor base electrode, and in series connection with said first diode, a second half of the remainder coupled between said input terminal and said first transistor collector electrode and in series connection with the collector-to-emitter path of said first transistor.
Claim 4
Dependent Claim
42 words
A current amplifier as claimed in claim 2 wherein said means coupling said second transistor collector electrode to said output terminal comprises a third transistor connected as a common base amplifier to couple said second transistor collector electrode to said output terminal.
Claim 5
Dependent Claim
35 words
A current amplifier as claimed in claim 3 wherein the base electrode of said third transistor is connected to an interconnection in the series connection of said second half of the remainder of said diodes.
References Cited (Backward Citations)
US3532909A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-02-24 | 1978-08-26 | 1979-02-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-24 | 1982-08-26 | 1983-02-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-24 | 1986-08-26 | 1987-02-25 | $7700.00 | Window Closed / Lapsed |