Hi…i could say about the functionality of the sensor which can help you to choose the one rather than looking for inexpensive sensors. The current through the liquid will be that voltage divided by the effective total liquid resistance through the hole and back around the outside of the pair of cores. The cylinder inside the cores will dominate this resistance since its length to width ratio is larger than the effective length to width ratio of the rest of the current path. When buying the one check the conductivity by keeping in mind about the flow.
printed circuit board
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