With the popularization of Internet of Things (IoT) technology, electrical products are increasingly developing towards high performance and small integration, and the design of circuit boards also tends to be high-density. During long-term use, this kind of high-density circuit board is prone to quality deterioration due to heat accumulation and component aging, and may even cause a fire. Although traditional fuse-type fuses can prevent fires caused by short circuits to a certain extent, in areas with extremely high safety requirements, such as database centers and automobile manufacturing, a single insurance measure is obviously insufficient. Therefore, this research aims to use advanced semiconductor gas sensor technology to detect odorous gases generated by circuit boards when they are overheated, so as to detect potential fire risks in advance.
Target products The gas sensor models selected for this study are TGS2600 , TGS2602 and TGS2603 . These sensors are widely used in the field of gas detection due to their high sensitivity and wide detection range.
Research content 1. Analysis of volatile gases produced by circuit boards
In order to understand what volatile gases are produced by circuit boards when they are overheated, we selected five different types of circuit boards, heated them to 250°C, and used gas chromatography The generated gases were analyzed using mass spectrometry and mass spectrometry. The results showed that each circuit board produced a variety of volatile gases, mainly including alcohols, amides, acids, ketones and aromatic compounds. The differences in the types and concentrations of these gases provide an important reference for our subsequent sensor selection.
2. Discussion on sensor selection and working voltage optimization
In order to find out the sensor sensitivity characteristics corresponding to the above five gases, as well as the most suitable working voltage, we conducted detailed experiments. Experimental results show that the sensitivity of
TGS2600 to various gases is relatively low, but the sensitivity balance is good;
TGS2602 shows a sensitivity similar to that of TGS2603 , and as the operating voltage increases, the sensitivity to aromatic gases increases significantly, and the sensitivity to aromatic gases increases significantly. The sensitivity balance of all gases is also very good;
while TGS2603 has almost no sensitivity to aromatic gases, but has higher sensitivity to alcohol and ketone gases. Considering that practical applications require sensors to have good balance for various gases, we selected TGS2602 with an operating voltage of 5V as the optimal sensor.
Sensitivity characteristics of various types of sensors
3. Volatile gas generation mechanism and sensor response confirmation
In order to verify the actual response effect of the sensor, we applied an overcurrent of 12A to the wiring template on the PCB circuit board in a sealed container , and simultaneously observed the changes in the resistance of the TGS2602 sensor and the state changes of the wiring template. The experimental results show that after applying overcurrent, the resistance value of the sensor drops immediately, indicating that the sensor has detected the presence of volatile gases. At the same time, we also observed that the wiring template produced certain gases. A strong odor could be smelled after 7 minutes, and the middle part of the wiring template had turned black. This further confirms the sensor’s effectiveness in detecting odorous gases produced by overheating of circuit boards.
Changes in TGS2602 sensor resistance and state changes in the wiring template caused by volatile gases generated on the circuit board after overcurrent is applied
Research Results This study successfully verified the feasibility of semiconductor gas sensors in detecting odorous gases generated by overheating of circuit boards through a series of experiments. By installing gas sensors in confined spaces or near sources of odorous gases, we can sense abnormal heating of circuit boards in the early stages of accidents before smoke or fire occurs. Compared with the currently popular wide-area (indoor) monitoring fire detection system, our method can sense the time point of abnormal conditions significantly in advance, thereby effectively preventing the occurrence of fires or controlling accident damage to a minimum.
For corporate customers who are interested in developing related technologies, please feel free to contact the technical engineers of Gongcai.com. We look forward to working with more partners to jointly promote the application and development of gas detection technology in the field of fire prevention
