US2128649A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thermionic valve circuits
Assignee: EMI Ltd
•
Filing: 1937-09-21
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Granted: 1938-08-30
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Expires: 1957-09-21
Abstract
No abstract record available.
Inventors
- 👤 Kinross Rupert Ivor
- 👤 Brown Walter John
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 02:21
CPC Classifications
H; H03; H03G; H03G1/00; H03G1/04; H03F; H03F1/00; H03F1/34; H03F1/36; H03J; H03J7/00; H03J7/02; H03J7/04
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1941-08-29 | 1942-02-28 | 1942-08-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1945-08-29 | 1946-02-28 | 1946-08-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1949-08-29 | 1950-02-28 | 1950-08-30 | $7700.00 | Window Closed / Lapsed |