Working Principle of GDT

Working Principle of Gas Discharge Tube：

Gas discharge tube generally uses ceramic as its packing housing. The discharge tube is filled with inert gases with stable electrical characteristics and provided with structure of two or three electrodes .When certain voltage is applied to interelectrode of discharge tube, nonuniform electric field will be produced. Gases begin to ionize under the effect of electric field. When applied voltage reaches interelectrode field intensity and exceeds the insulation strength of inert gas, the electric arc will be produced between the electrodes to ionize gas, and the negative resistance characteristic will be produced.Thus, the insulation state will be turned into conductive state immediately. i.e. when electric field strength exceeds the puncture strength of gas, the gap discharge will be caused, and interelectrode voltage will be limited. That is to say, when there is no surge, it will be in the state of open circuit. When surge occurs, the electrode plates in the discharge tube close and connect，allowing harmful current to be discharged via ground wire or circuit loop. When surge disappears, the discharge tube restores to the state of high impedance rapidly, and the circuit continues to work properly.