US1503709A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Vacuum-tube circuits
Assignee: AT&T Inc
•
Filing: 1923-04-03
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Granted: 1924-08-05
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Expires: 1943-04-03
Abstract
No abstract record available.
Inventors
- 👤 Harold M Pruden
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:33
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/52; H03F1/54; H03F1/542; H03F1/544
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) | 1927-08-05 | 1928-02-04 | 1928-08-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1931-08-05 | 1932-02-04 | 1932-08-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1935-08-05 | 1936-02-04 | 1936-08-05 | $7700.00 | Window Closed / Lapsed |