WRR-231 WRR-230 WRR-223 WRR-232 WRR-233 B thermocouples
WRR-231 WRR-230 WRR-223 WRR-232 WRR-233 B thermocouples, a varistor is a resistor whose resistance value changes with voltage within a certain range of current and voltage, or a resistor whose "resistance value is sensitive to voltage". The abbreviation is VDR. The material of the resistor body of a varistor is a semiconductor, so it is a variety of semiconductor resistors. "Zinc oxide" (ZnO) varistor is now used in large quantities. What is the use of a varistor? The biggest feature of a varistor is that when the voltage applied to it is lower than its threshold "UN", the current flowing through it is extremely small, which is equivalent to a closed valve. When the voltage exceeds UN, it flows through Its current surge is equivalent to the valve opening. With this function, abnormal overvoltages that often occur in the circuit can be suppressed, and the circuit can be protected from damage by overvoltage. Now the zinc oxide voltage is used in the power circuit of our home color TV The threshold voltage of the varistor used here is about 270V. When the power supply voltage is less than 270V (normal value is 220V), it is equivalent to non-conducting. When the power supply is abnormal and exceeds 270V for a short time, it will conduct ON, limiting the voltage to 270V, Anderson has upgraded the varistor.