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US3868664A
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Liquid level detecting circuits
Assignee: Lucas Electrical Co Ltd
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Filing: 1973-06-28
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Granted: 1975-02-25
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Expires: 1993-06-28
Abstract
Abstract A liquid level detecting circuit has an amplifier with a regenerative feedback path and a degenerative feedback path. One of the paths contains a plurality of series connected probes which control whether or not the amplifier oscillates, depending on the liquid level.
Inventors
- 👤 William Frank Hill
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 03:05
CPC Classifications
B; B60; B60T; B60T17/00; B60T17/18; B60T17/22; B60T17/225; G; G01; G01F; G01F23/00; G01F23/22; G01F23/26; G01F23/263
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
124 words
A liquid level detecting circuit for giving an indication when the level of liquid in either of two containers falls below a predetermined minimum, comprising a first pair of electrodes in one of said containers, a second pair of electrodes in the other of said containers, an amplifier incorporating a regenerative feedback path and a degenerative feedback path, the amplifier oscillating when the degree of regeneration exceeds the degree of degeneration, one of said feedback paths including the first pair of electrodes and the second pair of electrodes connected in series, whereby oscillation of the amplifier is controlled in accordance with the liquid level in both containers, and means for detecting oscillation of the amplifier, whereby the liquid level in both reservoirs is detected.
Claim 2
Dependent Claim
124 words
A liquid level detecting circuit for giving an indication when the level of liquid in either of two containers falls below a predetermined minimum, comprising a first pair of electrodes in one of said containers, a second pair of electrodes in the other of said containers, an amplifier incorporating a regenerative feedback path and a degenerative feedback path, the amplifier oscillating when the degree of regeneration exceeds the degree of degeneration, one of said feedback paths including the first pair of electrodes and the second pair of electrodes connected in series, whereby oscillation of the amplifier is controlled in accordance with the liquid level in both containers, and means for detecting oscillation of the amplifier, whereby the liquid level in both reservoirs is detected.
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) | 1978-02-24 | 1978-08-26 | 1979-02-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-24 | 1982-08-26 | 1983-02-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-24 | 1986-08-26 | 1987-02-25 | $7700.00 | Window Closed / Lapsed |