US2337423A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Negative feed-back amplifier
Assignee: AT&T Inc
•
Filing: 1942-10-01
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Granted: 1943-12-21
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Expires: 1962-10-01
Abstract
No abstract record available.
Inventors
- 👤 Albert L Stillwell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 22:28
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/34; H03F1/36
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) | 1946-12-20 | 1947-06-21 | 1947-12-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1950-12-20 | 1951-06-21 | 1951-12-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1954-12-20 | 1955-06-21 | 1955-12-21 | $7700.00 | Window Closed / Lapsed |