US3445596A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Capacitor microphone employing a field effect semiconductor
Assignee: International Standard Electric Corp
•
Filing: 1966-02-03
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Granted: 1969-05-20
•
Expires: 1986-02-03
Abstract
No abstract record available.
Inventors
- 👤 Cyril Francis Drake
- 👤 Michael Lawrence Gayford
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:34
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/181; H03F3/183; H03F3/185; H04; H04R; H04R19/00; H04R19/04; H04R23/00; H04R23/006
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2754431A
Cited
US3108162A
Cited
US3016752A
Cited
US3300585A
Cited
US3274462A
Cited
US3287506A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-05-19 | 1972-11-18 | 1973-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-05-19 | 1976-11-18 | 1977-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-05-19 | 1980-11-18 | 1981-05-20 | $7700.00 | Window Closed / Lapsed |