The Ceramic gas discharge tube can be used in all places that have over-voltages.We should decide the parameter of the GDTs base on the need of the actual circuit and then select the suitable GDTs,
otherwise,we may get the reverse result.The following is the notice when using  the Ceramic gas discharge tubes:

1)Must avoid affecting the normal operation of circuit when using the Ceramic gas discharge tube.
2)Confirm the maximum peak voltage that the circuit can bear,make sure that the GDT's impulse spark-over voltage must be lower than it
3)Based on the possible impulse current energy to select the necessary impulse discharge current volume of  the Ceramic gas discharge tube
4)When the over-voltage disappears, the GDTs must extinguish rapidly to avoid affecting the normal operation of the circuit.
5)If over-voltage lasts significantly longer, GDT's discharge may continue for an extended period and generate significant thermal energy
6)Select suitable volume of  the Ceramic gas discharge tube according to the applied space.

 Over-voltage transients often occur in electric circuit. Such abnormal voltages are often caused by lightning strikes,atmospheric lightning discharges,accidental contact between power and communications lines,unexpected rise in the supply voltages of the installation as a result of misoperation,and appearance of voltage higher than normal during switching operations.The over-voltage transients,if not properly taken care of, not only cause damage to delicate components such as semiconductors,ICs and others in the equipment,but also are highly dangerous to personnel.Thus,protection against over voltages is necessary for high reliability and long life of general electronic equipment.The better protection selection for the over-voltage transients is ceramic gas discharge tubes.

The Ceramic gas discharge tube is a switching component which is controlled by voltage.It is used to be parallel connected between the line and line of equipment,or between the line and the ground(show as the bottom figures).If the over-voltage doesn't reach GDT's action voltage,the ceramic gas discharge tube will be in high resistance status.If the over-voltage is higher than GDT's action voltage,the GDT's internal gap will then break down.The Ceramic gas discharge tube is almost short-circuit at this time and limits the over-voltage to almost 0 volt within 50ns,so the surge current can be led to ground rapidly and then the equipment can be protected safely.When the over-voltage disappears, the Ceramic gas discharge tube will extinguish and return to high insulation status,preparing for the next action.  

DC spark-over voltage:The voltage at which the ceramic gas discharge tube sparks over with gradully increasing DC voltage.

Impulse spark-over voltage: The highest voltage at which the ceramic gas discharge tube sparks over with given ware-shape at a rise speed 1000V/μs, and it is also called as “pulse voltage".

Holdover voltages : The maximum DC voltage across the terminals of a ceramic gas discharge tube under which it may be expected to clear and to return to the high impedance state after the passage of a surge, under specified circuit conditions.

Alternating discharge current : The r.m.s. value of an approximately sinusoidal alternating current passing through the ceramic gas discharge tube.

Impulse discharge current: The peak value of the impulse current passing through the ceramic gas discharge tube, and it is also called as pulse discharge current or surge discharge current, including 10/1000μs long-wave discharge current and 8/20μs short-wave discharge current.

Insulation resistance:DC resistance of the gas discharge tube under specified conditions. Test voltage must be lower than DC spark-over voltage.

Inter-electrode capacitance : The capacitance between any two electrodes in the gas discharge tube. Its value is mainly determined by the size of electrode and distance between electrodes. In addition, the capacitance is also related to the lead wire length, spacing and dielectric in the ceramic 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 inter-electrode of discharge tube, nonuniform electric field will be produced. Gases begin to ionize under the effect of electric field. When applied voltage reaches inter-electrode 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 inter-electrode 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.

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Kingtronics International Company was established in 1995 located in Dongguan City of China to handle all sales & marketing for factories located in Chengdu, Sichuan and Zhaoqing, Guangdong, China. In 1990, we established the first factory to produce trimming potentiometer and in 1999 we built up new factory in Zhao Qing, Guangdong. Now with around 850 workers, Kingtronics produce trimming potentiometers, dipped tantalum capacitors, multilayer ceramic capacitors, and diode & bridge rectifier. We sell good quality under our brand Kingtronics, and Kt, King, Kingtronics are our three trademarks. All our products are RoHS compliant, and our bridge rectifier have UL approval. Please visit our Products page, you could please download all our PDF datasheet and find cross reference for our Trimming Potentiometer and capacitors.

Tantalum and Ceramic Capacitors Cross Reference ↓ Download
Diodes & Rectifiers List(PDF: 97KB) ↓ Download
Trimming Potentiometer Cross Reference ↓Download

Meet Kingtronics in Moscow soon
Chip EXPO 2017
Chip EXPO 2017
"Expocentre" Moscow Russia
Date: Oct 31 - Nov 2nd, 2017
Booth No.: B 20

Meet Kingtronics in Munich soon
Electronica 2018
Electronica 2018
New Munich Trade Fair Centre, Germany
Date: 13-16 November, 2018
Booth No.: To be advised


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