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Selection Guide for Ceramic Gas Discharge Tube

view:1911

Date:2021-01-13

GDT ceramic gas discharge tube products are mainly composed of two or several metal electrodes with a certain gap between the electrodes, and a stable inert gas is filled between the electrodes, and a certain pressure is maintained. The ceramic is sealed and formed The protection device is called a ceramic gas discharge tube.


• It has a fast response speed, response time ≤100nS,
• It is a switch type parallel connection in the line to bypass the surge current, a lightning protection type protection device
•Voltage specifications range from 70V to 6000V, with strong surge current resistance ranging from hundreds of amperes to tens or even hundreds of thousands of amperes
• Diversified package dimensions, Φ5.5*6, Φ5.0*7.2, Φ8*6, Φ8*8, Φ8*10, Φ11, Φ20, Φ25, Φ32, 6.2*4.2, 4.0*4.2, 1812 (4532 ), 1206 and other ceramic gas discharge tubes of different specifications
• Low capacitance value, generally only a few picofarads
• No polarity, easy to install
•High insulation resistance, not easy to age, strong reliability
•Specially used for protection of high-frequency communication signal lines, generally cannot be directly used for protection on active circuits



Since ceramic gas discharge tube products have the problem of freewheeling and cannot be directly used for protection on active circuits, the protection on active products must use voltage-limiting protection devices (varistors or lightning protection devices, etc.) With the use of. Ceramic gas discharge tube products are widely used in consumer communication products to protect semiconductors and sensitive devices to prevent ICs from being damaged by the impact of transient overvoltage.
• Overvoltage and lightning protection of communication equipment: such as ADSL, MODEM, CATV, IC card telephones, Ethernet switches, network cards, voice splitters, telephones, fax machines, RS485, RS232 ports, antennas, mobile base stations, distribution frames , Duplexer, etc.
• Due to the high pulse breakdown voltage of the discharge tube, it is generally safer and more reliable to make two-pole protection when selecting and designing.



Ruilongyuan electronic ceramic gas discharge tube products comply with the corresponding provisions of RoHS WEEE and have passed the inspection of the corresponding testing institutions to meet the corresponding test standards: IEC61000-4-5, GB9043, ITU K21, IEC61643-311, GR1089, UL and other standards.
Selection principle of ceramic gas discharge tube


• DC spark-over voltage: It is defined as the breakdown voltage measured with a rising voltage of 100V/S or 1000V/S called the DC breakdown voltage, which is generally within the range of ±20% of the nominal DC breakdown voltage;
 •Impulse spark-over voltage: defined as the breakdown voltage measured with a rising voltage of 100V/uS or 1000V/uS, called the pulse breakdown voltage
• Nominal impulse discharge current: It is defined as the nominal impulse discharge current which refers to the 8/20μs lightning current that the discharge tube can withstand.
•AC discharge current: refers to the 50HZ mains power frequency AC current capacity that the discharge tube can withstand
• Insulation resistance: A certain voltage is applied to the two ends of the discharge tube, and the insulation resistance is tested
• Capacitance: refers to the selection of the parasitic capacitance value of the two ends of the discharge tube and the voltage of the ceramic gas discharge tube
• DC spark-over voltage: The DC breakdown voltage must be greater than the maximum working voltage of the protected circuit. Due to the high pulse breakdown voltage of the ceramic gas discharge tube, the secondary lightning protection idea should generally be considered when selecting and designing. Avoid high residual voltage and damage to the protected circuit IC. Selection of the flow rate of ceramic gas discharge tube
•Generally, it is selected according to the requirements of the customer's product lightning protection test level to determine the flow rate and corresponding size specifications of the selected discharge tube.

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