# IEC negate dependency (N) Canonical URL: https://eloragrid.ai/symbols/iec-negate-dependency-n Publisher: Elora Grid Updated: 2026-10-28 Lookup label: Nm Drawing use: Schematic Reference families: IEC, Manufacturer ## Symbol convention Convention: IEC Form: Affecting input labelled Nm with affected terminals labelled m Qualifying-symbol and dependency conventions as explained in TI's public overview of IEEE Std 91-1984, which incorporates IEC 617-12 work. Independent educational drawing; not certified IEC geometry or an IEC database identifier. Dependency label Nm: when the N input is active, affected terminals are complemented. ## In plain English ### What does IEC negate dependency (N) mean? N dependency is the negate or exclusive-OR relationship. When the Nm affecting input is at its internal 1 state, each affected input or output labelled m is complemented. At 0 it has no effect. The result is a controllable inverter folded into the device symbol. ### A simple example This notation appears on devices with selectable output polarity, such as programmable inverting or non-inverting buffers. Reading the N label tells the drafter that the same pin can produce either sense depending on the control input. ### What the drawings help you do The label does not indicate when the polarity may be changed during operation. That is a matter of device timing and system design. ### This particular reference Dependency label Nm: when the N input is active, affected terminals are complemented. Fixed output negation is a circle or triangle; N dependency makes the negation switchable. ### Terms - Normally open / normally closed: The contact state in the normal condition defined for the drawing. - Signal: Electrical information passed between devices, rather than necessarily the main power supply. - Schematic: A drawing showing function and connections rather than physical appearance. Concept diagram: Identify the device and form → Read the connections and state → Check the equipment reference A guide to reading this reference. The original symbol illustration and its drawing notes appear below; these boxes are not a wiring diagram. - [Overview of IEEE Standard 91-1984: explanation of logic symbols (SDYZ001A)](https://www.ti.com/lit/ml/sdyz001a/sdyz001a.pdf) ## What it represents N dependency is the negate or exclusive-OR relationship. When the Nm affecting input is at its internal 1 state, each affected input or output labelled m is complemented. At 0 it has no effect. The result is a controllable inverter folded into the device symbol. This notation appears on devices with selectable output polarity, such as programmable inverting or non-inverting buffers. Reading the N label tells the drafter that the same pin can produce either sense depending on the control input. The label does not indicate when the polarity may be changed during operation. That is a matter of device timing and system design. ## How to read it - An active N input inverts every terminal labelled with its number. - Check the state of the N control in each operating mode. ## Information to show or reference - Label the polarity control input as Nm. - Mark affected terminals with m. - State the default polarity in the sheet notes. ## Important distinction Fixed output negation is a circle or triangle; N dependency makes the negation switchable. ## Facts - Affecting input at 1: Complements state - Affecting input at 0: No effect - Artwork scope: Original educational illustration; consult the applicable standard and the selected device documentation for the exact graphic ## Public references - [Overview of IEEE Standard 91-1984: explanation of logic symbols (SDYZ001A)](https://www.ti.com/lit/ml/sdyz001a/sdyz001a.pdf) — Texas Instruments. N (negate) dependency description. ## Graphic scope Independent original educational concept illustration by Elora Grid. Not a certified standards graphic or manufacturer footprint. Unitless; not to scale. Original artwork licence: https://creativecommons.org/licenses/by/4.0/. Publisher material is linked only.