Patent US4225827A successfully refreshed from Google Patents.
US4225827A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Stabilization circuit for transistor RF power amplifiers
Assignee: Harris Corp
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Filing: 1979-02-21
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Granted: 1980-09-30
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Expires: 1999-02-21
Abstract
Abstract A stabilization circuit inhibits spurious oscillations of a Class C transistor power amplifier. A relatively large value resistor is connected in the base circuit of the amplifier transistor to inhibit the tendency of the amplifier to oscillate. A diode is added to the base circuit to prevent the possible failure of the transistor attendant to the use of the relatively high value resistor.
Inventors
- 👤 John F. Davis, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 22:24
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/08; H03F1/083; H03F3/00; H03F3/189; H03F3/19; H03F3/191; H03F3/20; H03F3/21
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
97 words
A Class C amplifier of the type used in radio communications having a stabilization circuit for preventing spurious oscillations in the output signal of the amplifier and for reducing the chances of transistor failure due to changing load conditions, comprising: an amplifying transistor biased to operate in the Class C mode of operation; a circuit element connected between the base and emitter junctions of said amplifying transistor for inhibiting spurious oscillations in the transistor; and means responsive to the voltage across said circuit element for limiting the base voltage of said amplifying transistor to prevent transistor failure.
Claim 2
Dependent Claim
97 words
A Class C amplifier of the type used in radio communications having a stabilization circuit for preventing spurious oscillations in the output signal of the amplifier and for reducing the chances of transistor failure due to changing load conditions, comprising: an amplifying transistor biased to operate in the Class C mode of operation; a circuit element connected between the base and emitter junctions of said amplifying transistor for inhibiting spurious oscillations in the transistor; and means responsive to the voltage across said circuit element for limiting the base voltage of said amplifying transistor to prevent transistor failure.
Claim 3
Dependent Claim
26 words
The stabilized Class C power amplifier of claim 1 wherein said circuit element comprises a resistor connected between the base and emitter junctions of said transistor.
Claim 4
Dependent Claim
22 words
The stabilized Class C amplifier of claim 2 wherein said voltage limiting means is a diode connected in parallel with said resistor.
Claim 5
Dependent Claim
26 words
The stabilized Class C amplifier of claim 1 wherein said voltage limiting means is a diode connected between the base and emitter junctions of said transistor.
Claim 6
Dependent Claim
33 words
The stabilized Class C power amplifier of claim 4 wherein said diode has a forward conduction voltage which is less than the voltage required to bias said amplifying transistor to a destructive point.
Claim 7
Independent Claim
96 words
A method for stabilizing the operation of a Class C power amplifier by substantially inhibiting the spurious oscillations inherent to such an amplifier and by reducing the chances of failure due to changing load conditions, comprising the steps of: providing an element of resistance between the base and emitter junctions of a transistor biased to operate in a Class C mode of operation, to inhibit spurious oscillations in the output signal of said amplifier; and limiting the voltage which can be developed across said resistance element to a predetermined value to prevent said transistor from failing.
Claim 8
Independent Claim
96 words
A method for stabilizing the operation of a Class C power amplifier by substantially inhibiting the spurious oscillations inherent to such an amplifier and by reducing the chances of failure due to changing load conditions, comprising the steps of: providing an element of resistance between the base and emitter junctions of a transistor biased to operate in a Class C mode of operation, to inhibit spurious oscillations in the output signal of said amplifier; and limiting the voltage which can be developed across said resistance element to a predetermined value to prevent said transistor from failing.
Claim 9
Dependent Claim
20 words
The method of claim 6 wherein said predetermined value is less than the maximum recommended base voltage for said transistor.
Claim 10
Dependent Claim
103 words
A stabilized Class C power transistor amplifier comprising: an amplifying transistor biased to operate in the Class C mode of operation; an impedance element having one terminal thereof connected to the base of said transistor; a resistor connected between the other terminal of said impedance element and the emitter of said transistor for inhibiting the inherent tendency of the transistor to oscillate; and a diode connected in parallel with said resistor such that said diode will become forward biased when the voltage across said resistor reaches a predetermined value less than the voltage required to bias said transistor to a point of failure.
Claim 11
Dependent Claim
103 words
A stabilized Class C power transistor amplifier comprising: an amplifying transistor biased to operate in the Class C mode of operation; an impedance element having one terminal thereof connected to the base of said transistor; a resistor connected between the other terminal of said impedance element and the emitter of said transistor for inhibiting the inherent tendency of the transistor to oscillate; and a diode connected in parallel with said resistor such that said diode will become forward biased when the voltage across said resistor reaches a predetermined value less than the voltage required to bias said transistor to a point of failure.
Claim 12
Dependent Claim
92 words
A Class C amplifier of the type used in radio communications having a stabilization circuit for preventing spurious oscillations in the output signal of the amplifier and for reducing the chances of transistor failure due to changing load conditions, comprising: an amplifying transistor biased to operate in the Class C mode of operation; means for applying a base bias voltage to said amplifying transitor sufficient to inhibit spurious oscillations in the transistor; and means responsive to said base voltage for limiting the base voltage of said amplifying transistor to prevent transistor failure.
Claim 13
Dependent Claim
92 words
A Class C amplifier of the type used in radio communications having a stabilization circuit for preventing spurious oscillations in the output signal of the amplifier and for reducing the chances of transistor failure due to changing load conditions, comprising: an amplifying transistor biased to operate in the Class C mode of operation; means for applying a base bias voltage to said amplifying transitor sufficient to inhibit spurious oscillations in the transistor; and means responsive to said base voltage for limiting the base voltage of said amplifying transistor to prevent transistor failure.
Claim 14
Dependent Claim
26 words
The stabilized Class C amplifier of claim 9 wherein said bias voltage applying means is a resistor connected between the base and emitter of said transistor.
Claim 15
Dependent Claim
22 words
The stabilized Class C amplifier of claim 10 wherein said limiting means is a diode responsive to the voltage across said resistor.
References Cited (Backward Citations)
US3513406A
Cited
US3984783A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-09-30 | 1984-03-31 | 1984-09-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-09-30 | 1988-03-31 | 1988-09-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-09-30 | 1992-03-31 | 1992-09-30 | $7700.00 | Window Closed / Lapsed |