The Influence of Environmental Temperature on GDT Ceramic Gas Discharge Tube

1. What is GDT

GDT (Gas Discharge Tube) is a ceramic gas discharge tube commonly used to protect electronic devices from transient voltage damage. GDT is a product filled with inert gas in a sealed ceramic body or glass tube with insulation gaps. Under normal circumstances, the operating voltage does not reach the breakdown voltage, and the gas discharge tube remains in a high resistance state. When the overvoltage reaches the breakdown voltage of GDT, gas discharge generates a plasma path, and GDT presents a short circuit. The filling gas begins to discharge, guiding the surge current to the ground to protect equipment safety. Once the overvoltage disappears, the gas discharge tube returns to a high resistance insulation state and waits for the next impact.

2. GDT operating temperature

The temperature range of GDT (Gas Discharge Tube) varies depending on manufacturing technology and design parameters. Generally speaking, its rated operating temperature range is between -40 ℃ and+85 ℃, but some models of GDT can operate normally over a wider temperature range, such as -55 ℃ to+125 ℃.

Shanghai Leiditech Electronics has two temperature ranges to meet customer needs: -40 ℃ to+90 ℃ and -40 ℃ to+125 ℃.

In practical applications, in order to ensure the service life and reliability of GDT, it is recommended to control its working temperature between -40 ℃ and+70 ℃. Under normal use, the temperature of the gas discharge tube usually does not have a great impact on its work, because its discharge phenomenon is mainly related to the gas pressure and structure. However, in extreme high or low temperature environments, the performance of gas discharge tubes may change. Therefore, when using, it is necessary to choose the appropriate model and parameters based on the actual environment, and pay attention to the influence of temperature, humidity, and other factors on the gas discharge tube. Under special temperature conditions, it is recommended to determine the performance of gas discharge tubes through testing and experimentation to ensure their performance and reliability.

The following figure shows the GDT provided by Shanghai Leiditech Electronics: 3R090-35 (storage and operating temperature -40.+125C). The actual breakdown voltage was tested at -55 ° C, and it can be seen that the voltage did not change much. Figure 1, Figure 2:

3. Main factors affecting the working temperature range of GDT

The working temperature range of GDT gas discharge tubes can be adjusted over a wide range, and there are several factors that affect the temperature range.

1) Material of GDT

GDT is usually made of materials such as glass or ceramics, and the thermal expansion coefficient of these materials changes with temperature. Among them, ceramics have higher heat resistance and can withstand higher temperatures, making them more suitable for use in high-temperature environments. For example, in applications that require working at 125 ° C, choosing ceramic GDT is a good choice.

If applied at -55 ° C, ceramic materials have better thermal expansion coefficient matching performance than glass.

2) Gas type and pressure of GDT

Different gases have different discharge characteristics under different pressures. Generally speaking, in high-temperature environments, using inert gases such as helium has better discharge performance, which can improve the stability and reliability of GDT operation.

For application scenarios in low-temperature environments, it is recommended to use standard gases (such as nitrogen) for filling. In addition, due to the variation of gas pressure in low-temperature environments, it is necessary to consider the impact of gas pressure under low-temperature conditions on GDT when designing GDT

3) Design parameters of GDT

GDT design parameters include value voltage, value current, discharge power, etc. In high-temperature environments, these parameters will also change with the increase of temperature, so it is necessary to adjust and compensate them accordingly to ensure the normal operation of GDT. When using GDT under low temperature conditions, appropriate parameter selection and design are required.

4) Protection circuit of GDT:

In low-temperature environments, as the electrical performance of GDT may change, it is necessary to design appropriate protective circuits to ensure the safe and reliable operation of GDT

In summary, in order for GDT to work properly, it is necessary to select materials, gases, and design parameters suitable for high and low environments, and adjust and optimize them accordingly. At the same time, in practical applications, strict testing and verification of GDT is also necessary to ensure its stable operation in high and low temperature environments for a long time.

4. Application field of GDT ceramic gas discharge tubes

GDT ceramic gas discharge tubes are widely used in telecommunications, network communication, and power systems, mainly playing a role in lightning protection, anti-interference, and voltage resistance. The following are some common application areas:

Communication equipment: As a protective component, GDT ceramic gas discharge tubes are widely used in telephone, data communication, and satellite communication equipment. It can effectively improve the lightning protection ability of equipment and protect communication lines from lightning strikes and other high voltage effects.

Power supply and inverter: GDT ceramic gas discharge tubes are also widely used in industrial and civilian power supply and inverter devices. These devices are often subject to interference from various voltages and radio frequency noise, and GDT can effectively prevent the transmission of these interference signals and ensure the normal operation of the power supply and inverter.

Lightning protection: GDT ceramic gas discharge tube is one of the most commonly used components in lightning protection. It can quickly direct lightning current to the ground, protecting electrical equipment and personal safety.

Medical equipment: GDT ceramic gas discharge tubes are also used in medical equipment, such as electronic biological instruments, cardiac pacemakers, and medical gas delivery systems. It can provide high levels of voltage and current protection to ensure the normal operation of medical equipment.

5. Typical Application Cases of Shanghai Leiditech Electronic GDT

As shown in the diagram at the bottom:

AC380V AC power surge protection scheme: MOV14D471/20D471/25D471, GDT2R600-8

AC220V AC power surge protection scheme: MOV14D471/20D471/25D471, GDT2R600-8L

10 Gigabit Ethernet 10G Interface Lightning and Static Protection Scheme

Option 1: ULC0542T, SMD4532-400NF

Option 2: ESDULC3311CDN, SMD4532-090NF, SMD5050-800

Gigabit network split lightning protection scheme: LC03CI, GDT3R090-5S

POE outdoor lightning protection scheme: LC3311CCW, GDT 3R090-5S, 14D820KJ, SMCJ58CA

RS485 Wave Filter Protector: SM712, SMD1812P050TF, 3R090-5S, PCI0420T-142-N

RS232 scheme: SMC12, SMD1812P050TF, 3R090-5S

WIFI antenna static surge protection scheme: ULC0511CDN, SMD4532-090NF

Shanghai Leiditech brand Leiditech can provide various interface electrostatic lightning protection solutions to solve electromagnetic compatibility problems for customers. For more protection solutions, please search for the mini program "EMC Electromagnetic Compatibility Community" on WeChat. Welcome to contact Hu Gong 18016225001.