Side-by-side reference

Understand the difference.

Compare the meaning, drawing context and source references of two entries. A similar graphic or shared abbreviation does not establish equivalence.

First referenceCompare with

GDT

IEEE / ANSI

ANSI/IEEE gas discharge tube symbol

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.

Drawing use: Schematic
Application: Connections & wiring
Reference family: IEEE / ANSI / Manufacturer
Form evidence: Autodesk IEEE-oriented protective gas discharge tube form. 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.

A distinction that matters

A gas discharge tube is a sealed gap; an open spark gap is exposed to ambient conditions.

Full reference

GDT

Symbols

Gas-discharge protection tube

A gas-discharge tube provides a documented surge-protection path through gas breakdown. The schematic identifies its protected terminals and the intended discharge connection.

Drawing use: SLD / Schematic
Application: Connections & wiring
Reference family: IEC / Manufacturer

A distinction that matters

A gas-discharge tube is a protection component, not a fuse-link.

Full reference

Original educational previews. Follow the source references on each full entry for the appropriate standard or selected product.