Patent US2613572A successfully refreshed from Google Patents.
US2208665A
Expired / Lapsed
US
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Amplifier circuits with controlled gain
Assignee: AT&T Inc
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Filing: 1937-09-04
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Granted: 1940-07-23
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Expires: 1957-09-04
Abstract
No abstract record available.
Inventors
- 👤 Theodore H Crabtree
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 23:10
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/34; H03F1/36; H03G; H03G7/00; H03G7/02; H03G7/04
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) | 1943-07-23 | 1944-01-22 | 1944-07-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1947-07-23 | 1948-01-22 | 1948-07-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1951-07-23 | 1952-01-22 | 1952-07-23 | $7700.00 | Window Closed / Lapsed |