| 摘要 |
<p>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.</p> |
