US1938640A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Intermediate frequency amplifier
Assignee: RCA Corp
•
Filing: 1932-01-25
•
Granted: 1933-12-12
•
Expires: 1952-01-25
Abstract
No abstract record available.
Inventors
- 👤 Posthumus Klaas
- 👤 Weyers Theodorus Josephus
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 15:31
CPC Classifications
H; H03; H03H; H03H7/00; H03H7/01; H03H7/0153; H03H7/0161; H03F; H03F3/00; H03F3/189; H03H7/17; H03H7/1741; H03H7/175; H03H7/0138; H03H7/0146; H03H7/1775
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) | 1936-12-11 | 1937-06-12 | 1937-12-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1940-12-11 | 1941-06-12 | 1941-12-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1944-12-11 | 1945-06-12 | 1945-12-12 | $7700.00 | Window Closed / Lapsed |