US2828439A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Space charge amplifier
Assignee: AT&T Inc
•
Filing: 1952-03-14
•
Granted: 1958-03-25
•
Expires: 1972-03-14
Abstract
No abstract record available.
Inventors
- 👤 Robert C Fletcher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 23:07
CPC Classifications
H; H01; H01J; H01J25/00; H01J25/34
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2289756A
Cited
US2367295A
Cited
US2424965A
Cited
US2653270A
Cited
US2566087A
Cited
US2641731A
Cited
US2643353A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1961-03-24 | 1961-09-23 | 1962-03-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-03-24 | 1965-09-23 | 1966-03-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-03-24 | 1969-09-23 | 1970-03-25 | $7700.00 | Window Closed / Lapsed |