The working principle of the gas discharge tube can be simply summarized as gas discharge. When a large amount of power between the two levels, the gap between the pole will be placed on the electrical breakdown, then it is transformed into a conductive state by the insulation state, this phenomenon is similar to the short circuit. When in the conductive state, the voltage between the two poles will be lower, generally between 20 ~ 50V, therefore, it can play a good role in the protection of the circuit.
Gas discharge tube using ceramic sealed, the internal by two or a plurality of band gap of the metallic electrode, filled with inert gas (argon or neon), the basic shape as shown in Figure 1. When applied to the two extreme voltage reaches the gas discharge tube gas breakdown, the gas discharge tube began to discharge, and is composed of a high resistance becomes low resistivity, the electrodes at both ends of the voltage does not exceed the breakdown voltage.
The main parameters of the gas discharge tube
Response time refers to from the applied voltage exceeds the breakdown voltage to produce breakdown time, gas discharge tube reaction time in u s number.
2) power capacity refers to the gas discharge tube can bear and emission maximum energy, its definition is in fixed 8 x 20 mu s current waveform, can bear and sporadic current.
3) capacity refers to the measured gas at the frequency of 1MHz under specific discharge capacity between two tubes. The gas discharge capacity is very small, generally less than 1pF.
4) when the voltage of the DC breakdown voltage rises at the rate of 500V/s, the voltage of the discharge tube is the breakdown voltage. Gas discharge tube with a variety of different specifications of the DC breakdown voltage, whose value depends on gas species and inter electrode distance and other factors.
5) the temperature range of the working temperature range between 55 DEG C 125.
6) insulation resistance refers to the application of gas measuring 50 or 100V DC voltage in discharge resistance, general >1010.
Telephone / fax machine and all kinds of communication equipment, lightning protection application, in the electronic system and the network line, often by outside of instantaneous voltage disturbances, these interference sources include: because the switching inductive load or start stop high power load, transmission line fault of operating voltage, due to lightning surges caused by lightning and other natural phenomena. This over-voltage (or over current) is called a surge voltage (or surge current), which is a transient disturbance. Surge voltage will seriously harm the safety of electronic systems. Eliminating the interference of the surge noise and preventing the surge is the core issue of the safe and reliable operation of the electronic equipment. In order to avoid the surge voltage damage electronic devices, the shunt defensive measures is surge voltage within a very short time and the earth shorted, enable the surge current shunt into the ground, to weaken and eliminate the over voltage and over current, so as to protect the electronic equipment operation.