压敏电阻的作用：The role of the varistor
它主要用于工作过程保护和吸收浪涌电流。如过压漏电保护开关里就是用压敏电阻做敏感元件。
It is mainly used for protection and absorb the surge current work process. Such as overvoltage in the electric leakage protection switch is to do with piezoresistive sensor.
1.保护作用。当电压过高时，其短路，熔断前级保险，起到保护后级电路的作用。
protective action. When the voltage is too high, the short circuit, fusing insurance level before, have the effect of protection level after circuit.
2.功率传输。在开关电源中，有些用到压敏电阻，震荡回路中累积起来一定电压后再击穿，使效率提高。
Power transmission. In the switching power supply, and some used varistor, accumulated a certain voltage oscillation loop breakdown again, to improve efficiency.
3.压敏电阻在电路中相当一个“安全阀”，当加在它上面的电压低于它的阀值“UN"时，流过它的电流极小。
Pressure sensitive resistance in the circuit is a "safety valve", when added to the voltage is lower than above its threshold "UN", the minimal current flows through it.
