Xiamen SET Electronics Co., Ltd.
Gas Discharge Tube (GDT) is a single-gap or multi-gap switching overvoltage protection device. Under normal circumstances, the GDT is in a high-impedance state; when suffer a surge, the GDT will change from a high-impedance state to a low-impedance state, and release the surge energy to the ground, reducing the residual voltage of the circuit, thereby protecting the equipment circuit or protect the human body from the hazards of transient overvoltage. GDT is formed by high-temperature sealing of metal electrodes, metallized ceramics, inert gas or other mixed gases.
Gas Discharge Tube (GDT) are widely used in overvoltage protection of signals, power supplies and various ports.
SETsafe | SETfuse's Gas Discharge Tube products have a voltage of 70 ~ 4500 V, a flow (@8/20 μs) 0.5 ~ 200 kA, a full range of safety certifications including: UL, cUL, TUV, and meet the RoHS, REACH requirements.
Vs
D.C. Spark-over Voltage
The voltage at which the GDT sparks over with slowly increasing d.c. voltage.
V
Impulse Spark-over Voltage
The highest Voltage which appears across the terminals of a GDT in the period between the application of an impulse of given wave-shape and the time when current begins to flow.
Va
Arc Voltage
Voltage drop across the GDT during arc current flow.
Vgl
Glow Voltage
The peak value of the voltage drop across the GDT when a glow-current is flowing, It is sometimes called the glow mode voltage.
8/20 μs
8/20Current Impulse
Current impulse with a nominal virtual front time of 8 µs and a nominal time to half-value of 20 µs.
1.2/50 μs
1.2/50 Voltage Impulse
Voltage impulse with a nominal virtual front time of 1.2 µs and a nominal time to half-value of 50 µs.
I
Alternating Discharge Current
The r.m.s. value of an approximately sinusoidal alternating current passing through the gas discharge tube.
In
Nominal Discharge Current
Crest value of the current through the GDT having a current waveshape of 8/20 µs.
Imax
Maximum Discharge Current
Crest value of a current through the GDT having an 8/20 µs waveshape and magnitude according to the manufacturers specification. Imax is equal to or greater than In.
Iimp
Impulse Discharge Current
Crest value of a discharge current through the SPD with specified charge transfer Q and specified energy W/R in the specified time.
Up
Impulse Discharge Current
Maximum voltage to be expected at the SPD terminals due to an impulse stress with defined voltage steepness and an impulse stress with a discharge current with given amplitude and waveshape.
UC
maximum r.m.s. voltage
Which may be continuously applied to the SPD's mode of protection.
If
follow current
Peak current supplied by the electrical power system and flowing through the SPD after a discharge current impulse.
SETsafe | SETfuse Quality Policy
Provide Industry-Leading Products
Raw-materials Supplier
Select critical raw materials: Must be from a manufacturer with quality management system (ISO9001, IATF16949) certification.
Annual or Quarterly Audits.
IQC (Incoming Quality Check)
AQL(MIL-STD-105E), Dimensions, Function, Visual Inspection, RoHS & REACH Test.
Document
Formulate corresponding incoming inspection specifications (01-QA-06-xxx) for each key material according to design data such as material technical indicators.
Testing Equipment and Tools
Projector, Tool Microscope, Salt Spray Tester, Universal Material Testing Machine, Spectrum Analyzer, etc.
Manufacturing Process
Online Inspection and Testing (Function 100% Automatic Testing).
Document
Process Flow Chart.
Failure Mode and Effects Analysis (FMEA).
Quality Control Flow Chart (QCFC).
Standard Inspection Procedure (SIP).
Work Instruction (WI).
Online Testing and Inspection
D.C. Spark-over Voltage Test (@100V/s) (100% Automatic Testing).
Insulation resistance Test system (100% Automatic Testing).
etc.
IPQC (In Process Quality Control) Inspection
AQL(MIL-STD-105E), Dimensions Inspection, Function Test, Visual Inspection.
FQC ( Final Quality Control)
AQL(MIL-STD-105E), Dimensions Inspection, Function Test, Visual Inspection, RoHS & REACH Test.
Reliability Test
Test specification (01-TE-01-xxx).
Including 17 items of appearance requirements, Electrical Performance, Mechanical Performance, Soldering Performance and Environmental test. e.g.
D.C. Spark-over Voltage Test（@100V/s）
Insulation resistance Test.
Impulse Discharge Current Test.
Low Temperature Test
High Temperature Test
etc.
OQC (Outgoing Quality Control)
AQL(MIL-STD-105E), Packaging, Labeling, Quantity Inspection.
Agency
Agency (Safety Certificate) Annual, Quarterly Audits.
Management System
ISO9001, (TUV approved and issued certificate).
ISO14001, ISO45001, etc.
Click to view the certificate
Environmental
RoHS & REACH Compliant.
SETsafe | SETfuse
Usage
1. Do not operate GDT in power supply networks, whose maximum operation voltage exceeds the minimum spark-overvoltage of the GDT.
2. The GDT may become hot in the event of longer periods of current stress (burn risk). In the event of overload the connectors may fail or the component may be destroyed.
3. If the contacts of GDT are defective, current load can cause sparks and loud noises.
4. When air pressure is from 55 kPa to 106 kPa. The relative altitude shall be +5000 m to –500 m.
Replacement
The GDT is a non-repairable product for safety sake, please use equivalent GDT for replacement.
Storage
The packaged GDT shoud be placed in a dry, ventilted and non-corrosive environment.
Installation Position
Do not install the GDT in a touchable position.
Mechanical Stress
Do not take violent action such as knocking when assembling, to avoid product failure.
Over Temperature Protection（80）
Over Voltage Protection（228）
Over Current Protection（51）
Active Protection（16）
Accessories（2）
