In the process of the lightning discharge, because the instantaneous discharge produces intense electromagnetic pulse, near the equipment or electronic circuit on the induction voltage surge current amplitude and change rate are very high, with devastating damage to some of the electronic devices, and overvoltage / surge protection device is to provide protection for all kinds of electronic equipment to avoid damage to electronic components, equipment of lightning surge. Varistor, gas discharge tube, TVS tube (instantaneous diode three) devices limit surge protection devices pressure type, have been used for surge protection in the circuit, but there are a lot of customers that TVS as the gas discharge tube and diode varistor. A TVS diode and a gas discharge tube, the varistor who limiting surge protection function / greater problem, how do you see?

There is a comparison to be able to highlight the pros and cons, so as to find the best solution. This trick is not in the market for investment or electronic protection device selection is applicable. But here actually can see someone say TVS as gas discharge tube and diode varistor, the many engineers do not agree. Engineers from the reaction time, flow capacity and working principle of the three aspects of the three kinds of overvoltage / surge protection device directly, but also deeply Xiaobian feel TVS diode is strong, the moment will be able to understand why the application scope of TVS diode so widely. From the electronic technology small series is not willing, the following is a FAE analysis of three electronic engineers from the three kinds of overvoltage / surge protection device quality:
In reaction time, the reaction speed of the TVS diode is the fastest, for picosecond, between the voltage sensitive resistor between TVS and a gas discharge tube, the varistor is slightly slower, nanosecond gas discharge tube; and the slowest, usually dozens of nanoseconds or more.
In the current capacity, the TVS diode is usually only a few hundred A; between the varistor between TVS and the same gas discharge, the varistor according to different specifications, to a single 8/20uS surge current through dozens of KA number KA; and for the gas discharge tube is usually ten KA level 8/20 S surge current conduction hundreds time.
In principle, the TVS diode based on the avalanche effect; varistors based on Zinc Oxide barrier between grains; and the gas discharge tube is based on gas discharge breakdown.
One can not ignore the characteristics of LED can be easily with other devices in a single chip, many of the existing EMI filtering and RFI protection function and TVS tube integrated with the device, not only reduce the number of devices used in the design to reduce the cost, but also avoid the PCB board wiring easily associated with self induced.