# IEC OR dependency (V) Canonical URL: https://eloragrid.ai/symbols/iec-or-dependency-v Publisher: Elora Grid Updated: 2026-10-28 Lookup label: Vm Drawing use: Schematic Reference families: IEC, Manufacturer ## Symbol convention Convention: IEC Form: Affecting input labelled Vm 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 Vm: affected terminals are ORed with the V input, forced to 1 when V is active. ## In plain English ### What does IEC OR dependency (V) mean? V dependency is the OR counterpart of G dependency. When the Vm affecting input is at its internal 1 state, every input or output labelled m is forced to its internal 1 state. When Vm is at 0, the affected signals act normally. ### A simple example Device symbols use V dependency to show override or force functions, for example an output that can be forced active regardless of the normal logic. Recognising the letter avoids misreading the affected output as purely driven by the main function. ### What the drawings help you do Like all dependency labels, V gives no timing information and does not imply a particular circuit. It is a compact statement of a logical relationship within the symbol. ### This particular reference Dependency label Vm: affected terminals are ORed with the V input, forced to 1 when V is active. G dependency is the AND relationship; V is the OR relationship. ### 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 V dependency is the OR counterpart of G dependency. When the Vm affecting input is at its internal 1 state, every input or output labelled m is forced to its internal 1 state. When Vm is at 0, the affected signals act normally. Device symbols use V dependency to show override or force functions, for example an output that can be forced active regardless of the normal logic. Recognising the letter avoids misreading the affected output as purely driven by the main function. Like all dependency labels, V gives no timing information and does not imply a particular circuit. It is a compact statement of a logical relationship within the symbol. ## How to read it - V forces affected terminals to 1; G forces them to 0. - Look for a bar over the number for complemented action. ## Information to show or reference - Label the affecting input with V and a number. - Mark every affected terminal with the same number. - Explain any override behaviour in the sheet notes. ## Important distinction G dependency is the AND relationship; V is the OR relationship. ## Facts - Affecting input at 1: Imposes 1 state - Affecting input at 0: Permits action - 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. V (OR) dependency description and summary table. ## 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.