2-wire and 3-wire DC sensors and interfacing considerations.

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Multiple Choice

2-wire and 3-wire DC sensors and interfacing considerations.

Two-wire and three-wire DC sensors differ in how they’re powered and how their output is delivered to the rest of the circuit. In a two-wire sensor, there are only two connections, so the sensor and the load share the same supply current—the sensor basically forms a simple current path in series with the load. In a three-wire sensor, there is separate power, ground, and a dedicated signal line, with the sensor’s output driven by its own output transistor independent of the power path. That’s why the statement is the best: it correctly describes the two-wire setup as a simple current path and the three-wire setup as having separate power, ground, and signal. The other choices misstate the hardware arrangement (two-wire having separate wires; three-wire always delivering more current) or the practical use (two-wire cannot be used with PLCs), which aren’t accurate in general.

Two-wire and three-wire DC sensors differ in how they’re powered and how their output is delivered to the rest of the circuit. In a two-wire sensor, there are only two connections, so the sensor and the load share the same supply current—the sensor basically forms a simple current path in series with the load. In a three-wire sensor, there is separate power, ground, and a dedicated signal line, with the sensor’s output driven by its own output transistor independent of the power path.

That’s why the statement is the best: it correctly describes the two-wire setup as a simple current path and the three-wire setup as having separate power, ground, and signal. The other choices misstate the hardware arrangement (two-wire having separate wires; three-wire always delivering more current) or the practical use (two-wire cannot be used with PLCs), which aren’t accurate in general.

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