{"schemaVersion":1,"slug":"iec-logic-identity-element","name":"IEC logic identity element","kind":"symbol","abbreviation":"=","aliases":["all-inputs-equal element","identity gate","= qualifier element"],"category":"logic-signals","drawingTypes":["Schematic"],"referenceFamilies":["IEC","Manufacturer"],"summary":"Element marked = whose output is active only when all inputs stand at the same logic state.","description":["The = qualifier defines a logic identity function: the output is active when every input is in the same state, whether all active or all inactive. For two inputs this is the equivalence or exclusive-NOR function, but with three or more inputs it is a distinct agreement check.","Identity elements are useful for voting and agreement logic, such as confirming that three redundant transmitters agree before allowing an action. The drawing should state what happens on disagreement, since the element only reports whether agreement exists.","The symbol does not provide majority selection. If two-out-of-three voting is intended, a different element or a combination of AND and OR elements is needed."],"readingNotes":["With three or more inputs, read = as all equal, not as majority.","Check what downstream logic does on a disagreement."],"drawingChecklist":["Use = only where full agreement is intended.","Label redundant inputs with their channel identifiers.","Show the disagreement response on the same sheet."],"distinction":"A negated =1 element means not exactly one active; it matches identity only for two inputs.","facts":[{"label":"Qualifier","value":"= (all inputs same state)"},{"label":"Two-input equivalent","value":"Exclusive-NOR"},{"label":"Artwork scope","value":"Original educational illustration; consult the applicable standard and the selected device documentation for the exact graphic"}],"references":[{"sourceId":"s28-ti-ieee91-logic-symbols","relevance":"Defines the = logic identity qualifier."}],"related":["iec-xnor-gate","logic-xnor-gate","iec-even-parity-element"],"artwork":"s28-iec-logic-identity-element","publishedOn":"2026-10-28","updatedOn":"2026-10-28","provenance":"independent-public-research","symbolVariant":{"convention":"IEC","form":"Rectangular element with the = general qualifier","reference":"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."},"plainEnglish":{"title":"What does IEC logic identity element mean?","introduction":"The = additional drawing mark defines a logic identity function: the output is active when every input is in the same state, whether all active or all inactive. For two inputs this is the equivalence or exclusive-NOR function, but with three or more inputs it is a distinct agreement check.","example":"Identity elements are useful for voting and agreement logic, such as confirming that three redundant transmitters agree before allowing an action. The drawing should state what happens on disagreement, since the element only reports whether agreement exists.","drawings":"The symbol does not provide majority selection. If two-out-of-three voting is intended, a different element or a combination of AND and OR elements is needed.","terms":[{"name":"Signal","meaning":"Electrical information passed between devices, rather than necessarily the main power supply."},{"name":"Schematic","meaning":"A drawing showing function and connections rather than physical appearance."}],"diagram":"flow","steps":["Identify the device and form","Read the connections and state","Check the equipment reference"],"caption":"A guide to reading this reference. The original symbol illustration and its drawing notes appear below; these boxes are not a wiring diagram.","sources":[{"label":"Overview of IEEE Standard 91-1984: explanation of logic symbols (SDYZ001A)","url":"https://www.ti.com/lit/ml/sdyz001a/sdyz001a.pdf"}],"detail":"Element marked = whose output is active only when all inputs stand at the same logic state. A negated =1 element means not exactly one active; it matches identity only for two inputs.","profileId":"reviewed-symbol-20261028"},"url":"https://eloragrid.ai/symbols/iec-logic-identity-element","illustration":{"url":"https://eloragrid.ai/tools/electrical-library/illustrations/iec-logic-identity-element.svg","scope":"Original educational concept; not an official standard graphic or product footprint","license":"https://creativecommons.org/licenses/by/4.0/"},"sources":[{"id":"s28-ti-ieee91-logic-symbols","title":"Overview of IEEE Standard 91-1984: explanation of logic symbols (SDYZ001A)","publisher":"Texas Instruments","url":"https://www.ti.com/lit/ml/sdyz001a/sdyz001a.pdf","type":"manufacturer","scope":"Public explanation of rectangular logic symbols, general qualifiers, input and output qualifiers, dependency notation, bistable elements and coders, consistent with IEC 617-12 work.","checkedOn":"2026-10-28","reuse":"link-only","relevance":"Defines the = logic identity qualifier."}]}