US3564402A
Expired / Lapsed
US
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Apparatus for measuring the strength and direction of magnetic fields utilizing a piezoelectric crystal
Assignee: Northrop Grumman Corp
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Filing: 1969-01-31
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Granted: 1971-02-16
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Expires: 1989-01-31
Abstract
Abstract A MULTIPLE AXIS FIELD SENSOR INCORPORATING FOR EACH AXIS A PIEZEOLECTRIC CRYSTAL ACTING AS A SPRING RESTRAINING AN ELECTROMAGNET EXCITED BY A REFERENCE VOLTAGE AGAINST ROTATION IN RESPONSE TO AN EXTERNAL FIELD, AND CIRCUIT MEANS CONTROLLED BY THE OUTPUT OF EACH CRYSTAL FOR PRODUCING A FIELD STRENGTH SIGNAL.
Inventors
- 👤 Roland Pittman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 15:41
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/02; G01R33/028
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) | 1974-02-15 | 1974-08-17 | 1975-02-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-15 | 1978-08-17 | 1979-02-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-15 | 1982-08-17 | 1983-02-16 | $7700.00 | Window Closed / Lapsed |