Varistors are sensitive elements in current applications, and are frequently used in photovoltaic power transformation, power industry and other fields. So, what kind of surge protection will this small varistor provide for the circuit system?

The first type of surge protection is realized by connecting the varistor with the power line or between the power line and the earth. As a varistor, its representative application is to protect electronic products under the condition that the power line and the long-distance transmission signal line meet lightning strike and the conductor has surge pulse. Generally, connecting the varistor between the lines is effective for the induction pulse between the lines, while connecting the varistor between the lines and the ground is effective for the induction pulse between the transmission line and the ground. If the two forms of line-to-line connection and line-to-ground connection are further combined, the surge pulse can be better absorbed.

The second type of surge protection is to realize the connection in the varistor load. This connection mode is mainly used to absorb the inductive pulse caused by the sudden opening and closing of the inductive load, so as to prevent the element from being damaged. Generally speaking, as long as it is connected to inductive load in parallel, it can be considered to be used with R-C series absorption circuit according to different types of current and energy.

The third surge protection is to realize the connection between the varistor contacts. This connection mode is mainly to prevent the inductive charge switch contacts from being burned by the arc. Generally, it is sufficient to connect the varistor in parallel with the contacts, which can play a good role in surge pulse absorption. In addition, the varistor can also provide the fourth kind of protection. This surge protection is mainly used for the protective connection of semiconductor devices. This connection method is mainly used for semiconductor devices such as silicon controlled rectifier and high-power triode. In practical operation, the mode of parallel connection with the protective device is generally adopted to limit the voltage below the withstand voltage level of the protected device, which is a kind of protection for semiconductor devices.