| 摘要 |
An electric alarm which includes a dual tone electronic chime, light emitting diode (LED) indicators, electronic circuitry, batteries, and with the exception of the AC adapter and the water sampler, all active and passive devices are housed in a small box to detect wet environments such as water that leaks from defective hot water heater tanks, flooded basements, storage spaces, room spaces below sea level, or any other spaces or tangible things not readily accessible or observable. It uses a water-activated-dielectric capacitor as a water sampler to absorb a small amount of water as the sample. And when it becomes wet or damp, the water dielectric signal controls the current required to energize the gate of the silicon control rectifier (SCR). In turn, the SCR turns "ON" a dual tone electronic chime and also turns "ON" a LED that simply glows. This action provides the audible and visual alert warning signals to indicate that the water does in fact exist. An automatic power supply change-over circuit is incorporated to allow the power failures of the primary power supply along with one of the two back-up power supplies to occur simultaneously or sequentially without interrupting the normal operation of this equipment.
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