| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method of detecting a liquid level using a resistance temperature sensor such that the resistance temperature sensor is prevented from deteriorating and the power consumption is suppressed. <P>SOLUTION: A liquid level detection device includes a liquid level sensor B with a pair of resistance temperature sensors 2a, 2b, and a device body A. The device body A includes a first constant voltage circuit 3a which applies a relatively large constant voltage to one 2a of the resistance temperature sensors; a second constant voltage circuit 3b which applies a fine constant voltage to the other 2b of the resistance temperature sensors; a resistance 4 interposed between the one of the resistance temperature sensors and the first constant voltage circuit, and the other of the resistance temperature sensors and the second constant voltage circuit; a first resistance value measuring circuit 7a which measures the resistance value of the one of the resistance temperature sensors; a second resistance value measuring circuit 7b which measures the resistance value of the other of the resistance temperature sensors; comparing means 8 of receiving and comparing the output of the first resistance value measuring circuit and the output of the second resistance value measuring circuit with each other; and control means 9 of controlling the operation of the whole device. <P>COPYRIGHT: (C)2012,JPO&INPIT |
