| 摘要 |
A circuit and apparatus for magnetically sensing fluid flow and applying voltage to a load. A valve disposed within a conduit is provided with a magnetic shield. A magnet is located on one side of the magnetic shield while a sensor, associated with the valve is located on the opposite side of the magnetic shield. The valve, and hence the magnetic shield, moves to permit fluid flow. When the magnetic shield moves due to fluid flow, the magnet activates the sensor. A load control circuit includes a supply terminal for receiving a supply voltage and a detector which detects a condition requiring the operation of a load. The detector causes a threshold voltage to be generated from the supply voltage, and a time delay controller controls the time required to generate the threshold voltage. A DIAC or equivalent element conducts to generate a first trigger signal once the threshold voltage is achieved, and a silicon-controlled rectifier (SCR) generates a second trigger signal in response to the first trigger signal. The circuit includes an opto-TRIAC and triac which are rendered conductive by the second trigger signal to cause a voltage to be provided to the load.
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