Industrial Engineer · phase 2 of 16 · noun

PNP Sensor

Three-wire DC sensor whose output sources positive current when active.

The Explain card

Plain English: A PNP sensor switches the positive supply through to its output wire when it detects something. It sources current, so the load sits between the output and DC common.
Example: A PNP proximity sensor on a cylinder has brown to plus 24 V, blue to common, and black to the input card. When a target is present, black goes to plus 24.
Why it matters: PNP is the default in most North American and European plants, and mixing in one NPN sensor gives you an input that reads backwards or never at all. Check the letter on the label before you trust the wiring.
Hook: PNP pushes positive.

How the word is built, where it came from, and what it sits beside in memory.

In a sentence

Wire the PNP Sensor output to the PLC input terminal, with the input common connected to 0 VDC.

Why these words

PNP electronics initialism for positive-negative-positive identifies the transistor-layer notation associated with the sensor output type
sensor Latin sentire, to perceive, with the agent suffix -or names the field device that detects a physical condition

Where it came from

Origin: PNP comes from mid-20th-century semiconductor notation for positive-negative-positive layers; sensor was formed from Latin sentire, to perceive
Entered the language: 20th century
What changed: PNP moved from naming a transistor structure to labeling an industrial sensor output convention, while sensor broadened from a sensing element to a complete detection device

How it is spelled

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What it sits beside

Same subject

Same shape

three-wire DC sensor labels

industrial sensing devices

Phase 2: PLC I/O and Field Signals

Where the controller meets the machine: discrete and analog signals, the wiring conventions behind them, and the field devices that send them.