US3531740A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pulse-width modulation circuit
Assignee: Duracell Inc USA
•
Filing: 1969-05-13
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Granted: 1970-09-29
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Expires: 1989-05-13
Abstract
No abstract record available.
Inventors
- 👤 Hans R Camenzind
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 05:25
CPC Classifications
H; H03; H03K; H03K7/00; H03K7/08
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-09-28 | 1974-03-30 | 1974-09-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-09-28 | 1978-03-30 | 1978-09-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-09-28 | 1982-03-30 | 1982-09-29 | $7700.00 | Window Closed / Lapsed |