In the field of protection of electronic devices, varistor is a key component and is widely used in overvoltage protection and voltage regulation. Varistors, marked MY, have different suffixes to indicate their different applications, such as J for household use, W for voltage regulation, G for overvoltage protection, P for high-frequency applications, L for lightning protection, and H for arc extinguishing. , and Z represents noise cancellation. Different manufacturers may have their own naming rules, but the basic principles and application areas are similar.
1. Working principle of varistor
The varistor is a special nonlinear resistor device, whose English name is Voltage Dependent Resistor (VDR), also known as Varistor. Unlike traditional resistors, varistors are not used to provide a continuous resistance value, but as a transient voltage suppression component. Its characteristic is that there are no fixed positive and negative poles, which is different from another common overvoltage protection component TVS. In practical applications, varistors are usually connected in parallel to integrated circuits (ICs) or circuits that need to be protected to achieve overvoltage protection.

2. Application characteristics of varistor
When the voltage applied to the varistor exceeds its predetermined threshold, its resistance will decrease rapidly, thereby conducting a larger current to protect the back-end circuit. On the contrary, when the voltage is lower than the operating voltage, the resistance of the varistor is extremely high, which is equivalent to an open circuit state, so it will not affect the normal operation of the back-end circuit. This characteristic makes varistors very effective under voltage fluctuations and surge conditions.
3. Limitations and precautions for varistor
Although varistors can absorb large surge energy, they cannot withstand large continuous currents. This means that this limitation of the varistor must be taken into account when designing overvoltage protection circuits. Generally, they are not suitable for sustaining currents exceeding milliamp levels. Therefore, when applying a varistor, it is necessary to fully understand and consider its working environment and the current levels it may encounter.
To sum up, varistor, as an efficient overvoltage protection component, plays an important role in the safety and stability of electronic equipment. Their nonlinear characteristics and fast response capabilities make them an integral part of protective circuit design. However, designers also need to consider their limited ability to withstand sustained current to ensure the safety and reliability of the entire electronic system. With the continuous development of electronic technology, the requirements for the performance and application fields of varistor will also continue to increase, prompting the continuous progress of this technology.