Relationship Between GDT Follow-Current Phenomenon and Active Gases

GDTs have long been used as surge protection for communication signal circuits. In recent years, there have been circuits that supply amperes to communication signal circuits, and improvements to the GDT have been desired. A gas discharge tube (GDT) is a component in which the gas inside is ionized by applying a voltage, allowing current to flow through it. Normally, a discharge occurs when the applied voltage exceeds a certain threshold. However, even if the applied voltage does not reach the threshold, a phenomenon in which the discharge continues temporarily (follow-on current) can be observed when a larger voltage is applied instantaneously while a voltage is applied. The follow-on current phenomenon is generally considered difficult to control, and once a discharge occurs, it may take longer than expected to stop. However, this experiment has revealed that this phenomenon is greatly influenced not only by the voltage and discharge start conditions, but also by the characteristics of the gas inside the GDT, and the conditions of the electrodes, including the gap and method. In this paper, experiments were conducted using multiple GDTs with different amounts of active gas, with the aim of clarifying the relationship between the discharge stop time and the active gas and other factors.