| 摘要 |
PURPOSE: A water level detector is provided to prevent an abnormal movement such as grounding caused by heating and damaging the clothing of a wire harness connected to an electrode bar. CONSTITUTION: A water level detector grounds a tool case to earth potential and detects a water level by using a pair of electrode bars(9a,9b) and a microcomputer(1). Signal amplifiers(4,5) amplify each signal for detecting a high water level and a low water level. The water level detector contains switching circuits(6,7), diodes(D1.D2), a level decider(3), a signal comparing amplifier(2) and a trouble checking circuit. The switching circuits switch the amplified signals and the diodes are connected to the head end of resistances(R5,R6). The level decider decides if a signal is for the high water level or the low water level. The signal comparing amplifier inputs voltage descent amount to the microcomputer after comparing and amplifying the amount. The trouble checker checks trouble by being turned on and off depending on the voltage descent amount.
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