| 摘要 |
The impedance of a soil/medium is inversely proportional to percentage of polar fluid in the soil/medium. There are many soil/medium moisture control devices that utilize the relation of soil/medium moisture and it's impedance but they generally are complicated devices both from an electronics and a user point of view. This invention uses a fluid detector circuit (based on a National Semiconductor, LM1830 microchip), impedances and a quad bilateral switch circuit to create a voltage divider circuit. This invention allows one to maintain the soil/medium impedance within a specified range (which corresponds to a range in moisture content for the soil/medium). This invention uses an ac signal, thus problems associated with plating of the probes are minimized.
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