Understand the difference.

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

F

IEC

Symmetric gas discharge tube

The publisher's IEC-oriented library lists a symmetric protective gas discharge tube separately from the standard form. The symmetric drawing presents both electrodes identically, emphasising that the device behaves the same for either polarity of surge, as is typical for AC and signal line protection.

Drawing use

Schematic

Application

Connections & wiring

Reference family

IEC / Manufacturer

Form evidence

Protective Gas Discharge Tube, Symmetric. Autodesk IEC-60617 Symbol Preview: Miscellaneous; vendor family reference, not certified IEC geometry.

A distinction that matters

The symmetric form draws identical electrodes; the standard gas discharge tube form may show the electrodes differently.

Full referenceAdd to legend

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 referenceAdd to legend

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