Can a float level switch have only one wire?
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For a float level switch that alerts when the liquid level is low, can it have only one wire, with the other end connected to ground through the metal enclosure? .
If you’re the boss, I suggest you stop doing this—it will eventually ruin the company
No. Using the casing as a signal line essentially means using grounding as the signal path. And the geopotential varies in different locations; it causes severe interference relative to the signal on another wire ； As the signal passes through various spaces, it picks up ambient electromagnetic waves. For two parallel wires, the magnitude and direction of the induced electromotive force can cancel each other out in relation to the signal, so no interference is caused. However, for two signal wires passing through different spaces, the magnitude and direction of the induced electromotive force cannot be the same, which results in interference on the signals ； .