{"schemaVersion":1,"slug":"iec-not-gate","name":"IEC NOT element (rectangular form)","kind":"symbol","abbreviation":"1","aliases":["IEC inverter","rectangular inverter","negator"],"category":"logic-signals","drawingTypes":["Schematic"],"referenceFamilies":["IEC","Manufacturer"],"summary":"Single-input IEC box marked 1 with a negation at the output, inverting the logic state.","description":["The IEC inverter is a single-input element carrying the qualifier 1, meaning the one input must be active, together with a negation at the output. The result is that the output is active when the input is inactive. Data books often replace the circle with a polarity triangle to show an active-low output.","Because negation can be drawn directly on any input or output, a standalone NOT box is often only used where an inverter really exists as a component or as a separate program instruction. On purely functional logic sheets drafters usually fold the inversion into the next element as a negated input.","The symbol gives no information about input thresholds. A Schmitt-trigger inverter adds the hysteresis qualifier; without it, slow or noisy inputs may not be handled cleanly."],"readingNotes":["Check whether the inversion is a real component or only a notation choice.","Look for a hysteresis mark if the input comes from a slow signal."],"drawingChecklist":["Mark the box with 1 and negate the output.","Avoid stacking inverters when a negated input would do.","Reference the device when the inverter is a discrete part."],"distinction":"A box marked 1 without output negation is a non-inverting buffer.","facts":[{"label":"Qualifier","value":"1 with output negation"},{"label":"Input count","value":"One"},{"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 1 qualifier and logic negation."},{"sourceId":"pub-electronics-ti-hc04","relevance":"Manufacturer inverter documentation."}],"related":["logic-inverter","iec-buffer","iec-schmitt-trigger-inverter"],"artwork":"s28-iec-not-gate","publishedOn":"2026-10-28","updatedOn":"2026-10-28","provenance":"independent-public-research","symbolVariant":{"convention":"IEC","form":"Single-input element marked 1 with output negation","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. The counterpart is the matching functional concept; no equivalence of every detailed standard graphic is asserted.","counterpart":"logic-inverter"},"plainEnglish":{"title":"What does IEC NOT element (rectangular form) mean?","introduction":"The IEC inverter is a single-input element carrying the additional drawing mark 1, meaning the one input must be active, together with a negation at the output. The result is that the output is active when the input is inactive. Data books often replace the circle with a polarity triangle to show an active-low output.","example":"Because negation can be drawn directly on any input or output, a standalone NOT box is often only used where an inverter really exists as a component or as a separate program instruction. On purely functional logic sheets drafters usually fold the inversion into the next element as a negated input.","drawings":"The symbol gives no information about input thresholds. A Schmitt-trigger inverter adds the hysteresis additional drawing mark; without it, slow or noisy inputs may not be handled cleanly.","terms":[{"name":"Normally open / normally closed","meaning":"The contact state in the normal condition defined for the drawing."},{"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"},{"label":"SN74HC04 — digital inverters","url":"https://www.ti.com/lit/ds/symlink/sn74hc04.pdf"}],"detail":"Single-input IEC box marked 1 with a negation at the output, inverting the logic state. A box marked 1 without output negation is a non-inverting buffer.","profileId":"reviewed-symbol-20261028"},"url":"https://eloragrid.ai/symbols/iec-not-gate","illustration":{"url":"https://eloragrid.ai/tools/electrical-library/illustrations/iec-not-gate.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 1 qualifier and logic negation."},{"id":"pub-electronics-ti-hc04","title":"SN74HC04 — digital inverters","publisher":"Texas Instruments","url":"https://www.ti.com/lit/ds/symlink/sn74hc04.pdf","type":"manufacturer","scope":"Public device-function and terminal documentation used as an example of digital inverters. Example part numbers are manufacturer identifiers, not IEC/IEEE symbol IDs. Device ratings, pin numbering and availability remain in the selected product documentation.","checkedOn":"2026-10-14","reuse":"link-only","relevance":"Manufacturer inverter documentation."}]}