Patent US2168393A successfully refreshed from Google Patents.
US4199732A
Expired / Lapsed
US
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Amplifying circuit
Assignee: Trio KK
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Filing: 1978-05-31
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Granted: 1980-04-22
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Expires: 1998-05-31
Abstract
Abstract An amplifying circuit comprising an input terminal to which an alternating current signal is applied; a first transistor; a second transistor where one of the first and second transistors is a NPN transistor and the other is a PNP transistor; an output terminal to which is connected the respective collectors of the first and second transistors means for operating the second transistor as a constant current source; and connecting means for connecting the alternating current signal at the input terminal to the respective bases of the first and second transistors where the connecting means includes a capacitor connected between the input terminal and the base of the second transistor to thereby connect to the second transistor substantially only those frequencies of the alternating current signal which are at least as high as the cut-off frequency of the first transistor although frequencies below the cut-off frequency may also be coupled to the second transistor in a further embodiment of this invention.
Inventors
- 👤 Tatsuhiko Okuma
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 22:17
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/42; H03F1/48; H03F3/00; H03F3/30; H03F3/3069; H03F3/3071
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
128 words
An amplifying circuit comprising an input terminal to which an alternating current input signal is applied; a first transistor; a second transistor where one of said first and second transistors is a NPN transistor and the other is a PNP transistor; an output terminal to which is connected the respective collectors of said first and second transistors; means for operating said second transistor as a constant current source; and frequency sensitive connecting means for connecting said input signal to the respective bases of said first and second transistors so that at frequencies above a predetermined frequency of said input signal, (a) said second transistor no longer functions as a constant current source and (b) said first and second transistors function as a push-pull amplifier for said input signal.
Claim 2
Dependent Claim
128 words
An amplifying circuit comprising an input terminal to which an alternating current input signal is applied; a first transistor; a second transistor where one of said first and second transistors is a NPN transistor and the other is a PNP transistor; an output terminal to which is connected the respective collectors of said first and second transistors; means for operating said second transistor as a constant current source; and frequency sensitive connecting means for connecting said input signal to the respective bases of said first and second transistors so that at frequencies above a predetermined frequency of said input signal, (a) said second transistor no longer functions as a constant current source and (b) said first and second transistors function as a push-pull amplifier for said input signal.
Claim 3
Dependent Claim
34 words
An amplifying circuit as in claim 1 including a differential amplifier to which an input signal is applied, and an emitter follower amplifier responsive to said differential amplifier to provide said alternating current signal.
Claim 4
Dependent Claim
51 words
An amplifying circuit as in claim 2 including load means connected between said collectors of said first and second transistors and an output amplifier having third and fourth transistors where the bases of said third and fourth transistors are respectively connected to the said collectors of said first and second transistors.
Claim 5
Dependent Claim
20 words
An amplifying circuit as in claim 1 where said predetermined frequency corresponds to the cut-off frequency of said first transistor.
Claim 6
Dependent Claim
30 words
An amplifying circuit as in claim 4 where said frequency sensitive connecting means includes at least one capacitor connected between said input terminal and said base of the second transistor.
Claim 7
Dependent Claim
23 words
An amplifying circuit as in claim 4 where the frequency spectrum of said alternating current input signal includes at least the audio frequencies.
Claim 8
Dependent Claim
20 words
An amplifying circuit as in claim 4 where said first transistor and second transistors are respectively NPN and PNP transistors.
Claim 9
Dependent Claim
127 words
An amplifying circuit comprising an input terminal to which an alternating current signal is applied; a first transistor; a second transistor where one of said first and second transistors is a NPN transistor and the other is a PNP transistor; an output terminal to which is connected the respective collectors of said first and second transistors; means for operating said second transistor as a constant current source; and connecting means for connecting said alternating current signal at said input terminal to the respective bases of said first and second transistors where said connecting means includes frequency sensitive means for connecting to said second transistor substantially only those frequencies of the alternating current signal which are at least as high as the cut-off frequency of said first transistor.
Claim 10
Dependent Claim
127 words
An amplifying circuit comprising an input terminal to which an alternating current signal is applied; a first transistor; a second transistor where one of said first and second transistors is a NPN transistor and the other is a PNP transistor; an output terminal to which is connected the respective collectors of said first and second transistors; means for operating said second transistor as a constant current source; and connecting means for connecting said alternating current signal at said input terminal to the respective bases of said first and second transistors where said connecting means includes frequency sensitive means for connecting to said second transistor substantially only those frequencies of the alternating current signal which are at least as high as the cut-off frequency of said first transistor.
Claim 11
Dependent Claim
29 words
An amplifying circuit as in claim 8 where said frequency sensitive means is at least one capacitor connected between said input terminal and said base of the second transistor.
Claim 12
Dependent Claim
22 words
An amplifying circuit as in claim 9 where the frequency spectrum of said alternating current signal includes at least the audio frequencies.
Claim 13
Dependent Claim
20 words
An amplifying circuit as in claim 8 where said first transistor and second transitors are respectively NPN and PNP transistors.
Claim 14
Dependent Claim
152 words
An amplifying circuit comprising an input terminal to which an alternating current signal is applied where the frequency spectrum of said alternating current signal includes at least the audio frequencies; a first transistor; a second transistor where one of said first and second transistors is a NPN transistor and the other is a PNP transistor; an output terminal to which is connected the respective collectors of said first and second transistors; means for operating said second transistor as a constant current source; and connecting means for connecting said alternating current signal at said input terminal to the respective bases of said first and second transistors where said connecting means includes frequency sensitive means for connecting to said second transistor substantially only those frequencies of the alternating current signal which are above a frequency which is one of said audio frequency but which is less than the cut-off frequency of said first transistor.
Claim 15
Dependent Claim
152 words
An amplifying circuit comprising an input terminal to which an alternating current signal is applied where the frequency spectrum of said alternating current signal includes at least the audio frequencies; a first transistor; a second transistor where one of said first and second transistors is a NPN transistor and the other is a PNP transistor; an output terminal to which is connected the respective collectors of said first and second transistors; means for operating said second transistor as a constant current source; and connecting means for connecting said alternating current signal at said input terminal to the respective bases of said first and second transistors where said connecting means includes frequency sensitive means for connecting to said second transistor substantially only those frequencies of the alternating current signal which are above a frequency which is one of said audio frequency but which is less than the cut-off frequency of said first transistor.
Claim 16
Dependent Claim
29 words
An amplifying circuit as in claim 12 where said frequency sensitive means is at least one capacitor connected between said input terminal and said base of the second transistor.
Claim 17
Dependent Claim
20 words
An amplifying circuit as in claim 13 where said first transistor and second transistor are respectively NPN and PNP transistors.
References Cited (Backward Citations)
US3760288A
Cited
US3883813A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-04-22 | 1983-10-22 | 1984-04-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-04-22 | 1987-10-22 | 1988-04-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-04-22 | 1991-10-22 | 1992-04-22 | $7700.00 | Window Closed / Lapsed |