| 摘要 |
PURPOSE:To make it possible to fix a water leakage detecting device to a supply terminal, by performing switching, selection, and the like of the gain of a water-leakage detecting amplifier and the reference voltage for determining in correspondence with a clock circuit, and improving detecting sensitivity. CONSTITUTION:In response to the set and reset outputs from a clock circuit 5, a relay 7 is energized by the set output of a flip flop 6, which memorizes the output of the clock circuit 5. The detected output of a water leakage sensor 1 is amplified by an amplifier 2. The output of the amplifier 2 through a switch C1 and a bandpass filter 3 is compared with a reference voltage. Then, switching of a switch C2 of a comparator 4, which judges the water leakage, is controlled. In this way, the gain of the amplifier 2 and the reference voltage for judging of the comparator 4 are switched and selected. During the midnight when external noises are decreased, water-leakage detecting sensitivity is enhanced. As a result, a water leakage detector can be fixed to the supply terminal of a water pipe, and the patrol inspection and the like are not required. |
