A gas discharge tube (GDT) is a type of protective device consisting of metal electrodes and metallized ceramics enclosed in a sealed space. It is filled with a discharge medium, such as an inert gas or gas mixture, at varying atmospheric pressures to create a single-gap or multi-gap switch. GDTs are designed to protect electronic equipment and systems from voltage surges or transients by providing a low-impedance discharge path.
GDTs have a high insulation resistance, low capacitance, and minimal leakage, ensuring that they have little to no impact on the normal operation of equipment. They are widely used in surge protectors, lightning arrestors, telecommunications systems, power distribution, automotive electronics, medical devices, industrial controls, and aerospace and defense
applications.