Patent US4180748A successfully refreshed from Google Patents.
US4180748A
Expired / Lapsed
US
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Electronic solid state switching device
Assignee: Communications Patents Ltd
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Filing: 1977-10-21
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Granted: 1979-12-25
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Expires: 1997-10-21
Abstract
Abstract A switch is described comprising a diode directly connected to the base of a transistor, the diode, the transistor and the connection therebetween forming part of a signal path between input and output terminals of the switch, and a solid state device for selectively controlling the potential of the connection between the diode and the transistor to render both the diode and the transistor either conductive or non-conductive.
Inventors
- 👤 Eric J. Gargini
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 15:41
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/51; H03K17/74; H04; H04H; H04H20/00; H04H20/65; H04H20/76
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
132 words
A solid state switching circuit comprising in combination, a diode, an output transistor with base and collector and emitter, a signal path input terminal directly connected at a junction to the base of said transistor through the diode, an ouput terminal of the switching circuit connected to the emitter of said transistor, and a solid state device connected for selectively controlling the potential of the connection junction between the diode and the transistor in an operating mode to render both the diode and the transistor simultaneously either conductive or non-conductive, with the switching circuit exhibiting a very high off impedance to the input circuit means by serial connection solely through said diode and the transistor base impedance, and a very low on impedance to the transistor base when the diode is conducting.
Claim 2
Dependent Claim
132 words
A solid state switching circuit comprising in combination, a diode, an output transistor with base and collector and emitter, a signal path input terminal directly connected at a junction to the base of said transistor through the diode, an ouput terminal of the switching circuit connected to the emitter of said transistor, and a solid state device connected for selectively controlling the potential of the connection junction between the diode and the transistor in an operating mode to render both the diode and the transistor simultaneously either conductive or non-conductive, with the switching circuit exhibiting a very high off impedance to the input circuit means by serial connection solely through said diode and the transistor base impedance, and a very low on impedance to the transistor base when the diode is conducting.
Claim 3
Dependent Claim
38 words
A switch according to claim 1, wherein the said connection is normally connected to a source of potential via a resistor such that when the solid state device is non-conductive the diode and the transistor are both conductive.
Claim 4
Dependent Claim
23 words
A switch according to claim 1, comprising means for selectively connecting the said connection to an auxiliary source of potential via said resistor.
Claim 5
Dependent Claim
55 words
A switch according to claim 1, wherein the solid state device comprises a further transistor with base and collector and emitter and means connecting a switching control signal to the base, the output emitter-collector impedance of the further transistor being connected in shunt directly between the said connection junction and a source of fixed potential.
Claim 6
Dependent Claim
21 words
A switch according to claim 4, wherein a smoothing capacitor is connected in shunt with the base of the further transistor.
References Cited (Backward Citations)
US3551703A
Cited
US3665220A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-12-24 | 1983-06-25 | 1983-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-12-24 | 1987-06-25 | 1987-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-12-24 | 1991-06-25 | 1991-12-25 | $7700.00 | Window Closed / Lapsed |