| 摘要 |
PROBLEM TO BE SOLVED: To obtain a level detector by which whether a liquid to be detected reaches a target level or not can be detected precisely even when a liquid having a resistance of 50 KΩ.cm or higher is to be measured, even when an area capable of detecting a level is narrow in the case of a spot soldering apparatus or the like and even when the detection area of a level is influenced badly by a high-temperature corrosive gas or the like. SOLUTION: The circumference of a linear detecting electrode 2 is covered with a tubular conductor 4 for interference prevention via an insulator 3. An operational amplifier 8 is connected across the electrode 2 connected to an AC power supply 7 and a judgment circuit 9 (used when whether a liquid 12 to be detected reaches a target level or not is judged on the basis of an input voltage value) in such a way that it constitutes a voltage follower circuit and that it is connected also to the connector 4. As a member for the detection of a level, a measuring electric wire 1 in which the long extended detecting electrode 2 is used as a core and in which a detection part 5 is provided at its tip is adopted.
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