{"schemaVersion":1,"slug":"ansi-gas-discharge-tube","name":"ANSI/IEEE gas discharge tube symbol","kind":"symbol","abbreviation":"GDT","aliases":["IEEE gas tube arrester","ANSI GDT","gas-filled surge protector"],"category":"connections-wiring","drawingTypes":["Schematic"],"referenceFamilies":["IEEE / ANSI","Manufacturer"],"summary":"IEEE-oriented protective gas discharge tube: electrodes within a sealed envelope that conduct when voltage exceeds breakdown.","description":["A gas discharge tube places protective electrodes inside a sealed gas-filled envelope, giving a more consistent breakdown voltage than an open spark gap. It is widely used on telecom lines, data interfaces and as part of hybrid surge protective devices. The publisher's IEEE miscellaneous preview lists a protective gas discharge tube form.","This illustration is independent and not the IEEE graphic. A GDT responds more slowly than semiconductor clamps and can hold a low on-state voltage, so it is often combined with other elements. The symbol does not show DC sparkover voltage or impulse rating."],"readingNotes":["Check DC sparkover and impulse ratings.","Look for companion clamp devices in hybrid protection."],"drawingChecklist":["State sparkover voltage.","Show earth connection.","Identify hybrid protection stages."],"distinction":"A gas discharge tube is a sealed gap; an open spark gap is exposed to ambient conditions.","facts":[{"label":"Convention evidence","value":"Autodesk IEEE Symbol Preview: Miscellaneous (Protective Gas Discharge Tube)"},{"label":"Public vendor block name","value":"HFU1_S00374 (Autodesk identifier; not an IEEE symbol number)"},{"label":"Standards context","value":"IEEE/ANSI 315-1975 covers diagram graphics; IEEE lists this edition as Inactive-Reserved."},{"label":"Preview","value":"Original educational illustration; consult the publisher and applicable standard for the exact graphic"}],"references":[{"sourceId":"ansi-autodesk-34282bfd-7b8e-48f3-a6ed-93adbdddfbd3","relevance":"Exact public IEEE-oriented category page listing the protective gas discharge tube form."},{"sourceId":"ieee-315","relevance":"Graphic-symbol standards context and official status; not a source of reproduced artwork."}],"related":["gas-discharge-protection-tube","ansi-spark-gap","iec-symmetric-gas-discharge-tube"],"artwork":"s28-ansi-gas-discharge-tube","publishedOn":"2026-10-28","updatedOn":"2026-10-28","provenance":"independent-public-research","symbolVariant":{"convention":"IEEE / ANSI","form":"Autodesk IEEE-oriented protective gas discharge tube form","reference":"Autodesk publishes this block under IEEE Symbol Preview: Miscellaneous. The counterpart is the matching functional concept; no equivalence of every detailed standard graphic is asserted.","counterpart":"gas-discharge-protection-tube"},"plainEnglish":{"title":"What does ANSI/IEEE gas discharge tube mean?","introduction":"A gas discharge tube places protective electrodes inside a sealed gas-filled envelope, giving a more consistent breakdown voltage than an open spark gap. It is widely used on telecom lines, data interfaces and as part of hybrid surge protective devices. The publisher's IEEE miscellaneous preview lists a protective gas discharge tube form.","example":"This illustration is independent and not the IEEE graphic. A GDT responds more slowly than semiconductor clamps and can hold a low on-state voltage, so it is often combined with other elements. The symbol does not show DC sparkover voltage or impulse rating.","drawings":"Check DC sparkover and impulse ratings. Look for companion clamp devices in hybrid protection. A gas discharge tube is a sealed gap; an open spark gap is exposed to ambient conditions.","terms":[{"name":"DC","meaning":"Direct current: electricity flowing in one direction."},{"name":"Rating","meaning":"A value stating the conditions for which equipment is specified."},{"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":"Autodesk IEEE Symbol Preview — Miscellaneous","url":"https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-34282BFD-7B8E-48F3-A6ED-93ADBDDDFBD3.htm"},{"label":"IEEE/ANSI 315-1975: graphic symbols for electrical and electronics diagrams","url":"https://standards.ieee.org/ieee/315/515/"}],"detail":"IEEE-oriented protective gas discharge tube: electrodes within a sealed envelope that conduct when voltage exceeds breakdown. A gas discharge tube is a sealed gap; an open spark gap is exposed to ambient conditions.","profileId":"reviewed-symbol-20261028"},"url":"https://eloragrid.ai/symbols/ansi-gas-discharge-tube","illustration":{"url":"https://eloragrid.ai/tools/electrical-library/illustrations/ansi-gas-discharge-tube.svg","scope":"Original educational concept; not an official standard graphic or product footprint","license":"https://creativecommons.org/licenses/by/4.0/"},"sources":[{"id":"ansi-autodesk-34282bfd-7b8e-48f3-a6ed-93adbdddfbd3","title":"Autodesk IEEE Symbol Preview — Miscellaneous","publisher":"Autodesk","url":"https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-34282BFD-7B8E-48F3-A6ED-93ADBDDDFBD3.htm","type":"cad-reference","scope":"Verified public IEEE-oriented vendor catalogue. Block names identify vendor symbols, not IEEE standard symbol numbers. Linked only; graphics and CAD files are not redistributed. IEEE/ANSI 315-1975 is a historical graphics reference with Inactive-Reserved status; this page does not certify current standards compliance.","checkedOn":"2026-10-14","reuse":"link-only","relevance":"Exact public IEEE-oriented category page listing the protective gas discharge tube form."},{"id":"ieee-315","title":"IEEE/ANSI 315-1975: graphic symbols for electrical and electronics diagrams","publisher":"IEEE Standards Association","url":"https://standards.ieee.org/ieee/315/515/","type":"standard","scope":"Graphic symbols and designation letters. IEEE lists this edition as Inactive-Reserved; it is a historical reference, not a claim of current compliance.","checkedOn":"2026-10-13","reuse":"link-only","relevance":"Graphic-symbol standards context and official status; not a source of reproduced artwork."}]}