Patent US4868508A successfully refreshed from Google Patents.
US4868508A
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Trouble detecting circuit for resistive sensor type indicator
Assignee: Yazaki Corp
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Filing: 1987-07-31
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Granted: 1989-09-19
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Expires: 2007-07-31
Abstract
Abstract In a resistive-sensor type indicator having a resistive sensor whose resistance changes according to a quantity to be measured and an indicator for indicating a sensor output voltage developed across the resistive sensor, when the resistive sensor is open due to disconnection or malconnection of the resistive sensor, the indicator indicates a maximum reading, thus resulting in a problem such that the user cannot recognize the abnormal state. To overcome this problem, a novel trouble detecting circuit is additionally incorporated in the indicator. The circuit comprises a comparator for outputting an abnormal signal when the sensor voltage exceeds a reference voltage and a transistor for grounding the resistive sensor in response to the abnormal signal. Therefore, the indicator indicates a minimum reading in case of resistive sensor trouble.
Inventors
- 👤 Shigeru Ohishi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 07:58
CPC Classifications
G; G01; G01F; G01F23/00; G01F23/22; G01F23/24; G01F23/246; G01R; G01R19/00; G01R19/165; G01R19/16566; G01R19/16576
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
160 words
A trouble detecting circuit for a resistive-sensor type indicator having a resistive sensor whose resistance changes according to a quantity to be measured and an indicator for indicating a sensor output voltage developed across the resistive sensor, which comprises: (a) means for comparing the sensor output voltage with a reference voltage and outputting a first signal indicative of a normal resistive sensor when the reference voltage exceeds the sensor output voltage and a second signal indicative of an abnormal resistive sensor when the sensor output voltage exceeds the reference voltage; and (b) means for controlling the sensor output voltage of said resistive sensor in such a way that said resistive sensor is connected to said indicator in response to the first signal to directly indicate a quantity to be measured on said indicator and to a substantially ground level in response to the second signal to indicate a minimum quantity on said indicator when said resistive sensor is in trouble.
Claim 2
Dependent Claim
160 words
A trouble detecting circuit for a resistive-sensor type indicator having a resistive sensor whose resistance changes according to a quantity to be measured and an indicator for indicating a sensor output voltage developed across the resistive sensor, which comprises: (a) means for comparing the sensor output voltage with a reference voltage and outputting a first signal indicative of a normal resistive sensor when the reference voltage exceeds the sensor output voltage and a second signal indicative of an abnormal resistive sensor when the sensor output voltage exceeds the reference voltage; and (b) means for controlling the sensor output voltage of said resistive sensor in such a way that said resistive sensor is connected to said indicator in response to the first signal to directly indicate a quantity to be measured on said indicator and to a substantially ground level in response to the second signal to indicate a minimum quantity on said indicator when said resistive sensor is in trouble.
Claim 3
Dependent Claim
69 words
The trouble detecting circuit as set forth in claim 1, wherein said comparing means is an operational amplifier having an non-inversion input terminal connected to said resistive sensor and an inversion input terminal connected to a reference voltage, for outputting a normal L-voltage level signal when the reference voltage exceeds the sensor output voltage and an abnormal H-voltage level signal when the sensor output voltage exceeds the reference voltage.
Claim 4
Dependent Claim
60 words
The trouble detecting circuit as set forth in claim 1, wherein said comparing means is a Zener diode having a cathode electrode connected to said resistive sensor, for outputting a normal L-voltage level signal when the reference Zener voltage exceeds the sensor output voltage and an abnormal H-voltage level signal when the sensor output voltage exceeds the reference Zener voltage.
Claim 5
Dependent Claim
61 words
The trouble detecting circuit as set forth in claim 1, wherein said sensor output voltage controlling means is a transistor turned off in response to the first signal to directly indicate a quantity to be measured on said indicator and turned on in response to the second signal to indicate a ground voltage level when said resistive sensor is in trouble.
Claim 6
Dependent Claim
133 words
A trouble-detecting circuit for a resistive-sensor type indicator having a resistive sensor whose resistance changes according to a quantity to be measured and an indicator for indicating a sensor output voltage developed across the resistive sensor, which comprises: (a) an operational amplifier having a first input terminal connected to said resistive sensor and a second input terminal connected to a reference voltage, for outputting a normal signal when the reference voltage exceeds the sensor output voltage and an abnormal signal when the sensor output voltage exceeds the reference voltage; and (b) a transistor, connected between said operational amplifier and the indicator, turned off in response to the normal signal to directly indicate a quantity to be measured on said indicator to indicate a ground voltage level when said resistive sensor is in trouble.
Claim 7
Dependent Claim
133 words
A trouble-detecting circuit for a resistive-sensor type indicator having a resistive sensor whose resistance changes according to a quantity to be measured and an indicator for indicating a sensor output voltage developed across the resistive sensor, which comprises: (a) an operational amplifier having a first input terminal connected to said resistive sensor and a second input terminal connected to a reference voltage, for outputting a normal signal when the reference voltage exceeds the sensor output voltage and an abnormal signal when the sensor output voltage exceeds the reference voltage; and (b) a transistor, connected between said operational amplifier and the indicator, turned off in response to the normal signal to directly indicate a quantity to be measured on said indicator to indicate a ground voltage level when said resistive sensor is in trouble.
Claim 8
Dependent Claim
134 words
A trouble detecting circuit for a resistive-sensor type indicator having a resistive sensor whose resistance changes according to a quantity to be measured and an indicator for indicating a sensor output voltage developed across the resistive sensor, which comprises: (a) a Zener diode having a cathode electrode connected to said resistive sensor, for outputting a normal signal when a reference Zener voltage exceeds the sensor output voltage and an abnormal signal when the sensor output voltage exceeds the reference Zener voltage; and (b) a transistor, connected between said operational amplifier and the indicator, turned of in response to the normal signal to directly indicate a quantity to be measured on said indicator and turned on in response to the abnormal signal to indicate a ground voltage level when said resistive sensor is in trouble.
Claim 9
Dependent Claim
134 words
A trouble detecting circuit for a resistive-sensor type indicator having a resistive sensor whose resistance changes according to a quantity to be measured and an indicator for indicating a sensor output voltage developed across the resistive sensor, which comprises: (a) a Zener diode having a cathode electrode connected to said resistive sensor, for outputting a normal signal when a reference Zener voltage exceeds the sensor output voltage and an abnormal signal when the sensor output voltage exceeds the reference Zener voltage; and (b) a transistor, connected between said operational amplifier and the indicator, turned of in response to the normal signal to directly indicate a quantity to be measured on said indicator and turned on in response to the abnormal signal to indicate a ground voltage level when said resistive sensor is in trouble.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-09-18 | 1993-03-20 | 1993-09-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-09-18 | 1997-03-20 | 1997-09-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-09-18 | 2001-03-20 | 2001-09-19 | $7700.00 | Window Closed / Lapsed |