US2974288A
Expired / Lapsed
US
⏱️ 0.0 years remaining
D.-c. amplifier and filter therefor
Assignee: HP Inc
•
Filing: 1957-10-09
•
Granted: 1961-03-07
•
Expires: 1977-10-09
Abstract
No abstract record available.
Inventors
- 👤 Donald E Norgaard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 00:44
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/38; H03F3/40
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2297543A
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US2546918A
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US2490579A
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US2688729A
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US2724022A
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US2637777A
Cited
US2903523A
Cited
US2806989A
Cited
US2884597A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1964-03-06 | 1964-09-05 | 1965-03-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-03-06 | 1968-09-05 | 1969-03-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-03-06 | 1972-09-05 | 1973-03-07 | $7700.00 | Window Closed / Lapsed |