Patent US2768291A successfully refreshed from Google Patents.
US2768291A
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US
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Electronic tube alarm circuit
Assignee: AT&T Inc
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Filing: 1952-04-21
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Granted: 1956-10-23
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Expires: 1972-04-21
Abstract
No abstract record available.
Inventors
- 👤 Lutomirski Karel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 10:59
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/52; H03F1/54
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1690271A
Cited
US1711663A
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US1462057A
Cited
US1503709A
Cited
GB355666A
Cited
US2326313A
Cited
US2261153A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1959-10-23 | 1960-04-23 | 1960-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1963-10-23 | 1964-04-23 | 1964-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1967-10-23 | 1968-04-23 | 1968-10-23 | $7700.00 | Window Closed / Lapsed |