A varistor, also known as a particle piezoresistive resistor, is an electronic component whose resistor has nonlinear resistance characteristics. Its application involves many fields, including circuit protection, overvoltage protection and generation of radio waves. In this article, we will delve into how varistors work, introducing you to their characteristics and applications.
A varistor is an electronic component that can change its resistance value as the pressure changes. In terms of basic principle, the varistor uses the electrical properties of the resistance material to obtain changes. The main component of the resistance material is zinc oxide (ZnO), which breaks the electron crystal by applying pressure to the resistance layer, so that the distance between particles is shortened. This allows for more efficient electrification and provides a smaller impedance.
Under the working conditions of a varistor, when an overvoltage occurs, the material will produce an electronic vacancy, so that the electrons in the material are excited. Now, when pressure is applied to the resistor, the charge accumulates on the shell of the resistor, reducing the electric field strength of the resistor. This can be done by changing the distance between the resistor and the ground. Since the current in the resistor is different, the charge recovers the defect by absorption.
Under the operating conditions of a varistor, when pressure is applied to the resistor, the charge change of the material is directly proportional to that pressure, and this change will cause the resistance value of the resistor to increase. This also varies with the resistance value of the material, thus providing the specified resistance.
In addition, because the basic principle of varistor is different from that of other resistors, it has nonlinear resistance characteristics. In other words, the resistance value of a varistor depends on the voltage, not just the current. This nonlinear resistance value makes varistors have important functions in circuit protection. For example, when the voltage in a circuit is unstable, a varistor can automatically detect overvoltage and prevent current from moving through the circuit. This overload protection can effectively prevent damage to electronic equipment.
In addition, the varistor also has the function of capturing, storing and releasing pulse signals. This can be used to produce radio waves, such as radar.
In short, varistor is an important electronic component with important application functions. Its working principle is very simple, but it is one of the factors that lead to the stability of electronic equipment. It is very important to ensure its reliability and quality to ensure the safety and stability of the operation of the machine and equipment.