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Gas Discharge Tubes
We are a prominent manufacturer, exporter and supplier of the finest quality Gas Discharge Tube. The provided tube is extensively used to protect personnel and sensitive equipment from transient voltages. This tube is manufactured using the premium quality raw materials under the guidance of our experienced professionals with the help of pioneering techniques. Further, the offered Gas Discharge Tube can be easily availed from us at affordable rates within promised time span.
- Easy installation
- High durability
- Shock resistance
- Long operational life
We are offering Gas Discharge Tube. The gas discharge tube may be regarded as a sort of very fast switch having conductance properties that change very rapidly, when breakdown occurs, from open-circuit to quasi-short circuit (arc voltage about 20V). There are accordingly four operating domains in the behavior of a gas discharge tube:
The GDT may be regarded as a very fast acting switch having conducting properties that change very rapidly when breakdown occurs and transforms from an open-circuit to a quasi-short circuit. The result is an arc voltage of about 20V DC. There are four stages of operation before the tube fully switches.
Non-operating domain: Characterized by practically infinite insulation resistance.
Glow domain: At the breakdown, the conductance increases suddenly. If the current is drained off by the gas discharge tube is less than about 0.5A (rough value that differs from component to component) , the glow voltage across the terminals will be in the 80-100V range.
Arc regime: As the current increases, the gas discharge tube shifts from glow voltage to the arc voltage (20V). It is this domain that the gas discharge tube is most effective because the current discharge can reach several thousand amperes without the arc voltage across the terminals increasing.
Extinction: At a bias voltage roughly equal to the glow voltage, the gas discharge tube covers to its initial insulating properties.
Protecting a two-wire line (for example a telephone pair) with two 2-electrode gas discharge tubes may cause the following problem:
If protected line is subjected to an over voltage in the common mode, the dispersion of the spark over voltages (+ 20%), one of the gas discharge tubes sparks over a very short time before the other (typically a few microseconds), the wire that has the spark over is therefore grounded (neglecting the arc voltages), turning the common-mode over voltage into a differential mode over voltage. This is very dangerous for the protected equipment. The risk disappears when the second gas discharge tube arcs over (a few microseconds later).
The 3-electrode geometry eliminates this drawback. The spark over of one pole causes a general breakdown of the device almost immediately (a few nanoseconds) because there is only one gas filled enclosure housing all the effected electrodes.
End of Life
The gas discharge tubes are designed to withstand many impulses without destruction or loss of the initial characteristics (typical impulse tests are 10 times x 5kA impulses for each polarity).
On the other hand, a sustained very high current, i.e. 10A rms for 15 seconds, with simulate the dropping out of the AC power line onto a telecommunication line and will take the GDT immediately out of service.
If a fail-safe end of life is desired, i.e. short circuit that will report a fault to the end user when the line fault is detected, the gas discharge tube with the fail-safe feature (external short-circuit) should be selected.
Selecting a Gas Discharge Tube
The information required to properly select a surge protector for your application is the following:
DC sparkover voltage (Volts)
Impulse sparkover voltage (Volts)
Discharge current capacity (kA)
Insulation resistance (Gohms)
Mounting (Surface Mount, Standard Leads, Custom Leads, Holder)
Packaging (Tape & Reel, Ammo pack)
Reange of DC sparkover voltage available:
High Voltage 500V
Very High Voltage 1000 to 3000V
*Tolerance on the breakdown voltage is generally +/-20%
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