Patent US4103245A successfully refreshed from Google Patents.
US4103245A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Transistor amplifier for low level signal
Assignee: Nippon Gakki Co Ltd
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Filing: 1976-08-17
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Granted: 1978-07-25
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Expires: 1996-08-17
Abstract
Abstract A transistor amplifier circuitry for low level signal which employs, as the amplifying element of at least its input state circuit, a transistor having a low input resistance. Thus, this transistor amplifier circuitry has a true (not apparent) input resistance sufficiently lower than the impedance of a signal source which may be connected to the transistor amplifier circuitry. Therefore, this transistor amplifier circuitry for low level signal is capable of amplifying, with a high S/N ratio, the signal from the signal source of a low impedance.
Inventors
- 👤 Kenji Yokoyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 20:55
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/30; H03F3/3066; H03F1/00; H03F1/26; H03F1/34; H03F1/56; H10; H10D; H10D62/00; H10D62/10; H10D62/13; H03F2200/00; H03F2200/366
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
132 words
An audio amplifier circuit for amplifying a signal of low voltage level supplied by a moving coil-type cartridge source, said amplifier comprising: an input terminal adapted to be connected to said signal source; an output terminal; a power source; a constant current circuit; a compound transistor including a plurality of transistors connected in parallel, said compound transistor having a base electrode, an emitter electrode, a collector electrode, and an input resistance of a value less than the value of impedance of said signal source; the base electrode being connected to the input terminal; the emitter electrode being grounded; the collector electrode being connected to the power source via said constant current circuit and also being connected to the output terminal; and a resistor connected between the output terminal and said input terminal.
Claim 2
Dependent Claim
132 words
An audio amplifier circuit for amplifying a signal of low voltage level supplied by a moving coil-type cartridge source, said amplifier comprising: an input terminal adapted to be connected to said signal source; an output terminal; a power source; a constant current circuit; a compound transistor including a plurality of transistors connected in parallel, said compound transistor having a base electrode, an emitter electrode, a collector electrode, and an input resistance of a value less than the value of impedance of said signal source; the base electrode being connected to the input terminal; the emitter electrode being grounded; the collector electrode being connected to the power source via said constant current circuit and also being connected to the output terminal; and a resistor connected between the output terminal and said input terminal.
Claim 3
Dependent Claim
215 words
An audio amplifier circuit for amplifying a signal of low voltage level supplied by a moving coil-type cartridge source, said amplifier comprising: an input terminal adapted to be connected to said signal source; an output terminal; a positive power source; a negative power source; a first power transistor of the PNP type, having a base electrode, an emitter electrode, a collector electrode, and an input resistance less than the value of impedance of said signal source; the base electrode being connected to the input terminal; the emitter electrode being connected to said positive power source via a first variable resistor and being connected to ground via a first capacitor; the collector electrode being connected to the output terminal; a second power transistor, of the NPN type, having a base electrode, an emitter electrode, a collector electrode, and an input resistance less than the value of impedance of said signal source; the base electrode of said second transistor being connected to the input terminal; the emitter electrode of said transistor being connected to said negative power source via a second variable resistor and being connected to ground via a second capacitor; the collector electrode of said second transistor being connected to the output terminal; and a resistor connected between said input terminal and said output terminal.
Claim 4
Dependent Claim
215 words
An audio amplifier circuit for amplifying a signal of low voltage level supplied by a moving coil-type cartridge source, said amplifier comprising: an input terminal adapted to be connected to said signal source; an output terminal; a positive power source; a negative power source; a first power transistor of the PNP type, having a base electrode, an emitter electrode, a collector electrode, and an input resistance less than the value of impedance of said signal source; the base electrode being connected to the input terminal; the emitter electrode being connected to said positive power source via a first variable resistor and being connected to ground via a first capacitor; the collector electrode being connected to the output terminal; a second power transistor, of the NPN type, having a base electrode, an emitter electrode, a collector electrode, and an input resistance less than the value of impedance of said signal source; the base electrode of said second transistor being connected to the input terminal; the emitter electrode of said transistor being connected to said negative power source via a second variable resistor and being connected to ground via a second capacitor; the collector electrode of said second transistor being connected to the output terminal; and a resistor connected between said input terminal and said output terminal.
Claim 5
Dependent Claim
267 words
An audio amplifier circuit for amplifying a signal of low voltage level supplied by a moving coil-type cartridge source, said amplifier comprising: an input terminal adapted to be connected to said signal source; an output terminal; a positive power source; a negative power source; a first compound transistor including a plurality of PNP-type transistors connected in parallel, said first compound transistor having a base electrode, an emitter electrode, a collector electrode, and an input resistance less than the value of impedance of said signal source; the base electrode being connected to said input terminl via a first resistor; the emitter electrode being connected to said positive power source via a series connection of a second resistor and a third resistor and being connected to ground via a first capacitor; the collector electrode being connected to the output terminal; a second compound transistor including a plurality of NPN-type transistors connected in parallel, said second compound transistor having a base electrode, an emitter electrode, a collector electrode and an input resistance less than the value of impedance of said signal source; the base electrode of said second compound transistor being connected to the input terminal via said first resistor; the emitter electrode of said second compound transistor being connected to said negative power source via a series connection of a fourth resistor and a fifth resistor and being connected to ground via a second capacitor; the collector electrode of said second compound transistor terminal connected to the output terminal; and a sixth resistor connected between said output terminal and the base electrodes of said first and second compound transistors.
Claim 6
Dependent Claim
267 words
An audio amplifier circuit for amplifying a signal of low voltage level supplied by a moving coil-type cartridge source, said amplifier comprising: an input terminal adapted to be connected to said signal source; an output terminal; a positive power source; a negative power source; a first compound transistor including a plurality of PNP-type transistors connected in parallel, said first compound transistor having a base electrode, an emitter electrode, a collector electrode, and an input resistance less than the value of impedance of said signal source; the base electrode being connected to said input terminl via a first resistor; the emitter electrode being connected to said positive power source via a series connection of a second resistor and a third resistor and being connected to ground via a first capacitor; the collector electrode being connected to the output terminal; a second compound transistor including a plurality of NPN-type transistors connected in parallel, said second compound transistor having a base electrode, an emitter electrode, a collector electrode and an input resistance less than the value of impedance of said signal source; the base electrode of said second compound transistor being connected to the input terminal via said first resistor; the emitter electrode of said second compound transistor being connected to said negative power source via a series connection of a fourth resistor and a fifth resistor and being connected to ground via a second capacitor; the collector electrode of said second compound transistor terminal connected to the output terminal; and a sixth resistor connected between said output terminal and the base electrodes of said first and second compound transistors.
Claim 7
Dependent Claim
234 words
An audio amplifier circuit for amplifying a signal of low voltage level, comprising: an input terminal; an output terminal; a positive power source; a negative power source; a first transistor, of the PNP type, having a collector electrode, an emitter electrode, a base electrode and a base spreading resistance not exceeding 10 ohms; the collector electrode being connected to said output terminal; the emitter electrode being connected to said positive power source via a series connection of a first resistor and a first variable resistor and being connected to ground via said first resistor and a first capacitor; the base electrode being connected to said input terminal by a parallel connection of a first diode and a second capacitor; a second transistor, of the NPN type, having a collector electrode, an emitter electrode, a base electrode and a base spreading resistance not exceeding 10 ohms; the collector electrode of the second transistor being connected to said output terminal; the emitter electrode of the second transistor being connected to said negative power source via a series connection of a third resistor and fourth resistor and being connected to ground via said third resistor and a third capacitor; the base electrode of the second transistor being connected to said input terminal by a parallel connection of a second diode and a fourth capacitor; and a fifth resistor connected between said input terminal and said output terminal.
Claim 8
Dependent Claim
234 words
An audio amplifier circuit for amplifying a signal of low voltage level, comprising: an input terminal; an output terminal; a positive power source; a negative power source; a first transistor, of the PNP type, having a collector electrode, an emitter electrode, a base electrode and a base spreading resistance not exceeding 10 ohms; the collector electrode being connected to said output terminal; the emitter electrode being connected to said positive power source via a series connection of a first resistor and a first variable resistor and being connected to ground via said first resistor and a first capacitor; the base electrode being connected to said input terminal by a parallel connection of a first diode and a second capacitor; a second transistor, of the NPN type, having a collector electrode, an emitter electrode, a base electrode and a base spreading resistance not exceeding 10 ohms; the collector electrode of the second transistor being connected to said output terminal; the emitter electrode of the second transistor being connected to said negative power source via a series connection of a third resistor and fourth resistor and being connected to ground via said third resistor and a third capacitor; the base electrode of the second transistor being connected to said input terminal by a parallel connection of a second diode and a fourth capacitor; and a fifth resistor connected between said input terminal and said output terminal.
Claim 9
Dependent Claim
110 words
An audio amplifier circuit for amplifying a signal of low voltage level supplied by a moving coil-type cartridge source, said amplifier comprising: an input terminal adapted to be connected to said signal source; an output terminal; a power source; transistor means including a plurality of transistors each having base, emitter and collector electrodes, said transistor means having an input resistance of a value less than the value of impedance of said signal source and the transistors being interconnected whereby corresponding electrodes of each transistor are connected, respectively, to the input terminal, the output terminal, and the power source; and a resistor connected between the output terminal and said input terminal.
Claim 10
Dependent Claim
110 words
An audio amplifier circuit for amplifying a signal of low voltage level supplied by a moving coil-type cartridge source, said amplifier comprising: an input terminal adapted to be connected to said signal source; an output terminal; a power source; transistor means including a plurality of transistors each having base, emitter and collector electrodes, said transistor means having an input resistance of a value less than the value of impedance of said signal source and the transistors being interconnected whereby corresponding electrodes of each transistor are connected, respectively, to the input terminal, the output terminal, and the power source; and a resistor connected between the output terminal and said input terminal.
Claim 11
Dependent Claim
35 words
An audio amplifier circuit as set forth in claim 5, wherein each of said transistors is a power transistor operated at a range where its emitter resistance exhibits the smallest values in its characteristic curve.
Claim 12
Dependent Claim
18 words
An audio amplifier as set forth in claim 5, wherein said plurality of transistors are connected in parallel.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-07-24 | 1982-01-23 | 1982-07-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-07-24 | 1986-01-23 | 1986-07-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-07-24 | 1990-01-23 | 1990-07-25 | $7700.00 | Window Closed / Lapsed |