The pressure sensitive resistance is a resistor device with nonlinear voltammetry, mainly for voltage clamping, absorbs excess current to protect sensitive devices when the circuit is overlapped. The English name is "Voltage Dependent Resistor" "VDR\\ The material is made of divalent element zinc (Zn) and six-price element oxygen (O). Therefore, from the perspective of material, zinc oxide pressure sensor is a "II-VI oxide semiconductor". In Taiwan, China The varistor is called a "soot absorber\\  
The pressure sensitive resistor is a restricted protected device. With the nonlinear characteristics of the pressure sensitive resistance, when the overvoltage occurs between the two poles of the pressure sensitive resistance, the pressure sensitive resistance can clamp the voltage to a relatively fixed voltage value, thereby realizing the protection of the post-stage circuit. The main parameters of the pressure sensitive resistance are: pressure sensitive voltage, flow capacity, junction capacitance, response time, and the like.  
The response time of the pressure sensitive resistor is NS level, which is fast than the gas discharge tube, slightly slower than the TVS tube. In general, the overvoltage protection of the electronic circuit can meet the requirements. The stem capacitance of the pressure-sensitive resistor is generally in the order of several hundred to thousands of PF, and in many cases, it is not appropriate to directly applied in the protection of high-frequency signal lines. When the protection of the AC circuit is used, because of its knot capacitance, it will increase the leakage. Current, need to be fully considered when designing protection circuitry. The flow capacity of the pressure sensitive resistance is large, but is smaller than the gas discharge tube. The pressure-sensitive resistor referred to as VDR is a nonlinear overvoltage protection semiconductor element that is sensitive to voltage.