Industrial Engineer · phase 2 of 16 · noun

Sinking / Sourcing

DC circuit convention describing whether a device provides the current return path or supplies current to the load.

The Explain card

Plain English: Sinking and sourcing describe which way current flows through a DC input or output. A sourcing device pushes current out to the load, and a sinking device pulls current in to common.
Example: A PNP sensor sources current, so it needs an input card that sinks. Wire it to a sourcing input card and the point never turns on.
Why it matters: The mismatch is the most common wiring error in a new panel and it produces no fault, just an input that stays off. Every sensor, card and drawing has to agree before power goes on.
Hook: Current has to have somewhere to go, and the card decides where.

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

In a sentence

Before wiring a sinking PLC input, connect the PNP proximity sensor output and verify the input common is tied to 0 V.

How it is built

Where it came from

Origin: Old English sincan, from Proto-West Germanic sinkwan, combined with the Germanic suffix -ing
Entered the language: c. 900
What changed: The physical sense of descending developed an electrical metaphor in current sink, from which sinking became a technical label for circuit and device configurations.

How it is spelled

Pattern: The base sink keeps its final k when -ing is added.
Pattern: The k is not doubled because sink already ends in the consonant cluster nk.

Spelled like

Broken into chunks

What it sits beside

Same subject

Same shape

DC I/O conventions

industrial sensor output types

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.