Gas Discharge Tubes

Gas discharge tubes (GDT) are used for overvoltage protection in low voltage power distribution networks. GDTs are hermetically sealed cells where the gas mixture between two electrodes becomes ionized with a rise in voltage, and some amount of current flow is enabled.

Construction of the GDT cell consists of four or five pieces combined into a compact product through manufacturing processes that involve vacuum techniques, noble gasses, clean rooms, material degasification and hermetically sealed joints. High quality GDTs must have the following characteristics: a defined spark, the ability to quickly extinguish arc current, repeatable manufacturing processes, high insulation resistance, and they must be fire safe.