Patent US3621276A successfully refreshed from Google Patents.
US3621276A
Expired / Lapsed
US
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Electric timing circuits
Assignee: Individual
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Filing: 1970-07-30
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Granted: 1971-11-16
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Expires: 1990-07-30
Abstract
Abstract An electric timing circuit to prevent the battery of a test instrument from being discharged if the instrument is left switched on when not in use. An amplifier and a capacitive element connected across the input circuit of the amplifier so that when the battery is connected across the capacitive element, the capacitive element charges up to effect closure of a current path through the circuit, and when the battery is disconnected from across the capacitive element, the capacitive element discharges thereby breaking the current path through the circuit after an interval determined by the rate of fall of the voltage across the capacitive element.
Inventors
- 👤 Cyril John Mitchell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:50
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/28
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
199 words
An electric timing circuit arrangement including an amplifier comprising first and second junction transistors of like conducTivity type each having a base, an emitter and a collector electrode; means directly connecting the collector electrodes of the first and second transistors; means directly connecting the emitter electrode of the first transistor to the base electrode of the second transistor; means connecting the base electrode of the first transistor to one terminal of a capacitive element; a third junction transistor of the same conductivity type as the first and second transistors and having a base, an emitter and a collector electrode; means directly connecting the emitter electrode of the second transistor to the base electrode of the third transistor; means connecting the emitter electrode of the third transistor to the other terminal of the capacitive element; an output terminal connected to the collector electrode of the third transistor, a first input terminal connected to said other terminal of the capacitive element; a second input terminal and a network including a switch, said network being connected between the first and second input terminals and connected to said one terminal of the capacitive element to provide a predetermined voltage across the capacitive element.
Claim 2
Dependent Claim
199 words
An electric timing circuit arrangement including an amplifier comprising first and second junction transistors of like conducTivity type each having a base, an emitter and a collector electrode; means directly connecting the collector electrodes of the first and second transistors; means directly connecting the emitter electrode of the first transistor to the base electrode of the second transistor; means connecting the base electrode of the first transistor to one terminal of a capacitive element; a third junction transistor of the same conductivity type as the first and second transistors and having a base, an emitter and a collector electrode; means directly connecting the emitter electrode of the second transistor to the base electrode of the third transistor; means connecting the emitter electrode of the third transistor to the other terminal of the capacitive element; an output terminal connected to the collector electrode of the third transistor, a first input terminal connected to said other terminal of the capacitive element; a second input terminal and a network including a switch, said network being connected between the first and second input terminals and connected to said one terminal of the capacitive element to provide a predetermined voltage across the capacitive element.
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) | 1974-11-15 | 1975-05-17 | 1975-11-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-15 | 1979-05-17 | 1979-11-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-15 | 1983-05-17 | 1983-11-16 | $7700.00 | Window Closed / Lapsed |