US2234687A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Balanced vacuum tube circuit
Assignee: AT&T Inc
•
Filing: 1939-11-25
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Granted: 1941-03-11
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Expires: 1959-11-25
Abstract
No abstract record available.
Inventors
- 👤 Horace T Budenbom
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 22:29
CPC Classifications
H; H03; H03G; H03G7/00; H03G7/02
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) | 1944-03-10 | 1944-09-09 | 1945-03-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1948-03-10 | 1948-09-09 | 1949-03-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1952-03-10 | 1952-09-09 | 1953-03-11 | $7700.00 | Window Closed / Lapsed |