The electronic protection device is to escort the circuit safety, to ensure that the precision electronic components and functional devices are not damaged when the circuit is abnormal, and the area affected by the disaster is reduced. The common fuse is the fusing fuse in the light bulb and the fuse in the switch, which acts as an overcurrent. Once the current or temperature is too high, it will automatically trip. So what is a resettable fuse? According to the literal meaning, it seems to be able to automatically return to normal working conditions. Is it so magical?
Self-recovery fuse is a kind of over-current electronic protection component. It is made of high-molecular organic polymer under the conditions of high pressure, high temperature and vulcanization reaction, mixed with conductive particle materials, and processed by a special process. Self-recovery fuse (PPTC: polymer self-recovery fuse) is a positive temperature coefficient polymer thermistor used for overcurrent protection and can replace current fuse. According to the actual market demand, the self-recovery fuses developed and produced by Quanye Electronics are divided into two types: patch self-recovery fuses and plug-in self-recovery fuses. Let's take a look at the function of the patch self-recovery fuse with the editor below, and further understand the magical automatic recovery function of the self-recovery fuse.
The temperature during normal operation is low, and the heat generated and the heat dissipated reach a balance. The PPTC element is in a low-resistance state, and the PPTC does not operate. When the current flowing through the PPTC element increases or the ambient temperature rises, the PPTC still does not operate if the balance between the generated heat and the emitted heat is reached. When the current or ambient temperature increases again, the PPTC will reach a higher temperature. If the current or ambient temperature continues to increase at this time, the heat generated will be greater than the heat dissipated, causing the temperature of the PPTC element to increase sharply. At this stage, a small temperature change will cause a substantial increase in resistance. At this time, the PPTC element is in High resistance protection status. After troubleshooting, the PPTC element will cool down quickly and will return to the original low resistance state, so that it can work again like a new PPTC element.