US5028875A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Linear rotary differential capacitance transducer
Assignee: Texas Tech University
•
Filing: 1989-04-27
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Granted: 1991-07-02
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Expires: 2009-04-27
Abstract
Abstract A bridge-type capacitance transducer is disclosed. The transducer utilizes a coaxially mounted circular stator and circular rotor to form the capacitance bridge. An excitation voltage is applied to the bridge. The output voltage of the bridge is conditioned by synchronous detection so as to yield a signal proportional to the degree of rotation of the rotor.
Inventors
- 👤 Randall D. Peters
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-10 01:41
CPC Classifications
G; G01; G01D; G01D5/00; G01D5/12; G01D5/14; G01D5/24; G01D5/241; G01D5/2412
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
128 words
A rotary differential capacitance transducer, comprising: a circular stator comprising two semicircular conductive plates separated by an insulating strip and being rigidly mounted to a frame; a circular rotor comprising two semicircular conductive plates separated by an insulating strip, rotatably and coaxially mounted in proximity to the stator so that the stator and rotor are separated by a constant spacing, the stator and rotor together forming a bridge-type capacitance network; a voltage excitation source for applying an A.C. voltage across the conductive plates of the stator; a differential amplifier for measuring the potential difference between the conductive plates of the rotor, which drives a synchronous detector whose reference is provided by the excitation source and whose output voltage is proportional to the degree of rotation of the rotor.
Claim 2
Dependent Claim
128 words
A rotary differential capacitance transducer, comprising: a circular stator comprising two semicircular conductive plates separated by an insulating strip and being rigidly mounted to a frame; a circular rotor comprising two semicircular conductive plates separated by an insulating strip, rotatably and coaxially mounted in proximity to the stator so that the stator and rotor are separated by a constant spacing, the stator and rotor together forming a bridge-type capacitance network; a voltage excitation source for applying an A.C. voltage across the conductive plates of the stator; a differential amplifier for measuring the potential difference between the conductive plates of the rotor, which drives a synchronous detector whose reference is provided by the excitation source and whose output voltage is proportional to the degree of rotation of the rotor.
Claim 3
Dependent Claim
27 words
The transducer as set forth in claim 1 wherein the inputs to the differential amplifier are by means of wires to the conductive plates of the rotor.
Claim 4
Dependent Claim
85 words
The transducer as set forth in claim 1 further comprising: a capacitance pick-up plate comprising two conductive sections separated by insulating material, nonrotatably and coaxially mounted in proximity to the rotor, wherein over a certain range of rotation of the rotor the potential difference between the two conductive sections of the pick-up plate varies as the potential difference between the two semicircular conductive plates of the rotor, the inputs to the differential amplifier being connected by wires to the conductive sections of the pick-up plate.
Claim 5
Dependent Claim
30 words
The transducer as set forth in claim 3 wherein the capacitance pick-up plate is circular in shape having two oppositely oriented quarter sections of conductive material separated by insulating material.
References Cited (Backward Citations)
US3198937A
Cited
US3121839A
Cited
US3296522A
Cited
US3337789A
Cited
US3732553A
Cited
US3729991A
Cited
US3845377A
Cited
US3938113A
Cited
US4023413A
Cited
US4092579A
Cited
US4439725A
Cited
US4720698A
Cited
US4788546A
Cited
US4755731A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-07-01 | 1994-12-31 | 1995-07-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-07-01 | 1998-12-31 | 1999-07-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-07-01 | 2002-12-31 | 2003-07-02 | $7700.00 | Window Closed / Lapsed |