The Gas Discharge Tube (GDT) is a protective device
which is filled with certain proportion of noble gas, or
mixed gas or other discharge media in the space
between metal electrodes and metalized ceramics,
and then sealed at high temperature to form a singlegap or multi-gap switch type protective device. When
the protected circuit or equipment suffers to surge, GDT
will change from high impedance state to low impedance state and release the surge energy to reduce the
residual voltage of the circuit, and then protect the
equipment or humanbody from the hazard of transient
overvoltage.