From 1929 to 1930, the United States and Germany almost simultaneously made high-voltage arresters with silicon carbide pressure-sensitive materials. At the end of the 1940 s, the Soviet Union made low-voltage silicon carbide varistors. In 1968, Japan developed a zinc oxide pressure sensitive material. This material has more excellent electrical properties than other materials, and is still widely used. Other metal oxide (Fe2O3, TiO, etc.) varistors have also been developed.

Varistor is a kind of solid-state voltage-sensitive element with nonlinear volt-ampere characteristics and transient overvoltage suppression. When the terminal voltage is lower than a certain threshold, the current of the varistor is almost equal to zero; beyond this threshold, the current value increases sharply as the terminal voltage of the varistor increases. The nonlinear volt-ampere characteristics of the pressure-sensitive resistor are caused by the change of the voltage drop of the pressure-sensitive body (or pressure-sensitive junction), so it is also called a nonlinear resistor. The table lists common varistor classes. In the power industry, pressure-sensitive materials are often used to make lightning arrester valves. Reverse characteristics of the selenium rectifier and avalanche diodes also have pressure-sensitive characteristics, but it is customary to continue to use their original names.

Varistors are mainly used to limit harmful atmospheric overvoltage and operating overvoltage, can effectively protect the system or equipment. The high-voltage insulator made of zinc oxide pressure-sensitive material has both insulating effect and transient overvoltage protection. In addition, varistors can be used in electronic circuits for spark elimination, noise elimination, voltage stabilization and function transformation. With the development of the electronics industry, computers, mobile phones, set-top boxes and other industries continue to develop and grow, varistors have also been welcomed by the market. However, the development of the varistor industry will also be hindered by some reasons.

1) Competition within the varistor industry. There may be several reasons for increased competition within the industry:

One is the slow growth of the industry, the fierce competition for market share:

Second, the number of competitors is relatively large, and the competitive power is roughly equal;

Third, the products or services provided by competitors are roughly the same, or only rarely reflect obvious differences;

Fourth, some enterprises in order to the interests of economies of scale, expand the scale of production, the market balance is broken, a large number of products surplus, enterprises began to resort to price competition.

2) The bargaining power of customers in the varistor industry. Industry customers may be consumers or users of industry products, or they may be buyers of goods. The bargaining power of the customer is reflected in the ability to induce the seller to lower the price, improve the quality of the product or provide better service.

3) The bargaining power of suppliers in the varistor industry is reflected in the ability of suppliers to effectively induce buyers to accept higher prices, earlier payment times or more reliable payment methods.

4) The threat of potential competitors in the varistor industry. Potential competition will bring new production capacity and share existing resources and market share. As a result, the production cost of the industry will rise, the market competition will intensify, the product price will decrease and the profit of the industry will decrease.

5) The pressure of alternative products in the varistor industry refers to the competitive pressure of products that have the same function or can meet the same needs and can replace each other.

The development of varistor in addition to grasp their own development situation also want to get more market resources and competition. Through competition, the survival of the fittest is realized, and the optimal allocation of production factors is realized.