Read this article! Understand the causes and solutions of varistor burnout

Varistor is a resistor commonly used in electronic components. It has a wide range of applications, including power supply systems, security systems, household appliances and other fields. However, no matter what product it is, there will always be some minor problems over time, and varistors are no exception. A customer asked our company for help. He said that the varistor was used well in the circuit, but suddenly burned out. He didn't know what caused the varistor to burn out, and asked how to solve this problem. After collecting information online and asking our engineers, the editor summarized the causes and solutions for the burnout of varistors.

1. Reasons why the varistor burns out:

1) Aging failure

As the varistor is used for a long time, the resistance value of the varistor becomes lower, the leakage current increases, and when the current is poured into the short-circuit point of the varistor, high heat is generated and fire occurs.

2) Transient overvoltage damage

Strong transient overvoltages cause holes in the resistor, leading to greater current and high heat. The whole process occurs in a short period of time, causing the thermal welding points of the varistor to burn out before they can melt.

3) Whether it has passed quality certification

If the varistor fails to pass the quality certification, it means that the varistor is of unqualified quality and cannot be used by customers. Using unqualified varistors may cause problems such as short circuit and burning.

4) Ambient operating temperature

The operating temperature of the circuit or product surroundings exceeding the operating temperature of the varistor may also cause the varistor to burn out.

5) The operating voltage exceeds the rated voltage of the varistor

If the working voltage applied to the varistor by the product or circuit greatly exceeds the rated voltage of the varistor, the varistor will be broken down and damaged.

2. Solution:

Thermal fuse technology is used to solve the problem of varistor burning. Thermal fuse technology is a process in which a low-melting-point metal protected by wax is installed on the varistor. When the leakage current of the varistor is too large, the temperature will rise. When the temperature rises to a certain level, the low-melting-point metal will melt, preventing the varistor from catching fire.

After knowing the reasons why the varistor burns out, I believe everyone knows what to do when encountering such a problem. When purchasing a varistor, you should still find a regular varistor manufacturer to purchase the varistor. In this way, the probability of problems during use is much lower than that of inferior varistors.