US4392383A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Distance-frequency transducer
Assignee: Robert Bosch GmbH
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Filing: 1981-03-17
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Granted: 1983-07-12
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Expires: 2001-03-17
Abstract
Abstract The distance-frequency transducer includes a capacitor whose capacitance changes as a function of movement of one electrode relative to the other. The movement is controlled by the parameter to be measured, as, for example, the pressure in a pressure pickup. The capacitance determines the frequency of an RC oscillator. The output frequency of the oscillator can be calibrated directly in pressure units.
Inventors
- 👤 Hans Bauerlen
- 👤 Thomas Pfendler
- 👤 Berthold Wocher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 05:33
CPC Classifications
G; G01; G01L; G01L9/00; G01L9/0082; G01L9/0086; G01D; G01D5/00; G01D5/12; G01D5/14; G01D5/24; G01D5/241; G01D5/2417
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
103 words
Pressure transducer comprising an RC oscillator circuit including a measuring capacitor having a capacitance (C) varying in dependence on pressure, and determining the frequency of the RC oscillator circuit, said capacitor having a fixed electrode (E1) and a movable electrode (E2); wherein the fixed electrode comprises a layer of electrically conductive material surrounding a central area which comprises non-conductive material (100), and wherein the movable electrode comprises a metallic, corrugated membrane (M) having a surface facing said fixed electrode, said membrane (M) forming a pressure pick-up (D) and being movable relative to said fixed electrode (E1) as a function of pressure applied thereon.
Claim 2
Dependent Claim
103 words
Pressure transducer comprising an RC oscillator circuit including a measuring capacitor having a capacitance (C) varying in dependence on pressure, and determining the frequency of the RC oscillator circuit, said capacitor having a fixed electrode (E1) and a movable electrode (E2); wherein the fixed electrode comprises a layer of electrically conductive material surrounding a central area which comprises non-conductive material (100), and wherein the movable electrode comprises a metallic, corrugated membrane (M) having a surface facing said fixed electrode, said membrane (M) forming a pressure pick-up (D) and being movable relative to said fixed electrode (E1) as a function of pressure applied thereon.
Claim 3
Dependent Claim
23 words
A transducer as set forth in claim 1, wherein said RC oscillator circuit means comprises an integrator circuit and a Schmitt trigger circuit.
Claim 4
Dependent Claim
34 words
A transducer as set forth in claim 2, wherein said integrator circuit comprises a charging resistor (R 2 ); further comprising a compensating capacitor (C K ) connected in parallel to said charging resistor.
Claim 5
Dependent Claim
56 words
A transducer as set forth in claim 2, wherein said integrator circuit comprises an operational amplifier having a direct input; wherein said measuring capacitor has a fixed electrode (E1) and a ring electrode (E5) surrounding said fixed electrode; and further comprising means for electrically connecting said ring electrode to said direct input of said operational amplifier.
Claim 6
Dependent Claim
41 words
A transducer as set forth in claim 1, further comprising a printed circuit board (I); wherein said fixed electrode is on said printed circuit board; further comprising a housing having a first and second part (G1, G2) enclosing said pressure pickup.
Claim 7
Dependent Claim
23 words
A transducer as set forth in claim 1, further comprising a trimmer capacitor (C P ) connected in parallel to said measuring capacitor.
Claim 8
Dependent Claim
35 words
A transducer as set forth in claim 6, wherein said RC oscillator circuit means comprises an integrated circuit having a charging resistor; further comprising a compensating capacitor (Ck) connected in parallel to said charging resistor.
Claim 9
Dependent Claim
21 words
A transducer as set forth in claim 5, wherein said oscillator circuit means is mounted on said printed circuit board (1).
Claim 10
Dependent Claim
59 words
A transducer as set forth in claim 5, wherein said printed circuit board (I) constitutes a first printed circuit board; further comprising a second printed circuit board carrying said oscillator circuit means, said second printed circuit board being mounted underneath said first part (G1) of said housing; further comprising a hood for electrically shielding said RC oscillator circuit means.
Claim 11
Dependent Claim
88 words
Distance-frequency transducer comprising an RC oscillator circuit including an operational amplifier having a direct input forming an integrator circuit; a Schmitt trigger circuit connected to the integrator circuit; and a measuring capacitor having a capacitance (C) varying in dependence on distance, connected to said operational amplifier, for controlling the frequency thereof in dependence on the capacitance of the capacitor; said capacitor having a fixed electrode (E1) and a ring electrode (E5) surrounding said fixed electrode, said ring electrode being connected to the direct input of the operational amplifier.
Claim 12
Dependent Claim
88 words
Distance-frequency transducer comprising an RC oscillator circuit including an operational amplifier having a direct input forming an integrator circuit; a Schmitt trigger circuit connected to the integrator circuit; and a measuring capacitor having a capacitance (C) varying in dependence on distance, connected to said operational amplifier, for controlling the frequency thereof in dependence on the capacitance of the capacitor; said capacitor having a fixed electrode (E1) and a ring electrode (E5) surrounding said fixed electrode, said ring electrode being connected to the direct input of the operational amplifier.
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) | 1986-07-11 | 1987-01-10 | 1987-07-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-07-11 | 1991-01-10 | 1991-07-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-07-11 | 1995-01-10 | 1995-07-12 | $7700.00 | Window Closed / Lapsed |