Patent US2729753A successfully refreshed from Google Patents.
US2729753A
Expired / Lapsed
US
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Electrical circuits employing spark gaps
Assignee: AT&T Inc
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Filing: 1954-09-16
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Granted: 1956-01-03
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Expires: 1974-09-16
Abstract
No abstract record available.
Inventors
- 👤 Raymond W Ketchledge
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 20:16
CPC Classifications
H; H03; H03K; H03K19/00; H03K19/02
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) | 1959-01-02 | 1959-07-04 | 1960-01-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1963-01-02 | 1963-07-04 | 1964-01-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1967-01-02 | 1967-07-04 | 1968-01-03 | $7700.00 | Window Closed / Lapsed |