The main characteristic of varistor terms - it's main parameters Knowledge of electrical resistance

by:Thermistor-Mov     2020-06-21
Varistor is mainly introduced in this paper the main characteristic of the main parameters of terminology, this article word count 1340 words, read the full text to 13 minutes. One, the main characteristics of varistor 1, wide working voltage range, 6 ~ 3000 v, several files) On the overpressure impulse response fast ( Nanosecond) , the ability of impact resistance current ( 100~2000A) Small, leakage current, Microamps level) , the temperature coefficient of resistance is small, cheap cheap, small volume, is an ideal protection element, can form overvoltage protection circuit, de-noising, quenching circuit, absorption circuit. Overvoltage in power supply network stack when the pulse, varistor, peak overvoltage waveform work-pieces, limited within a certain range. In the open or closed with the perception, the capacitive load circuit, dc switch spike pulse waveform appeared, pressure sensitive resistance in a circuit can absorb the electric work potential, thus protecting switch circuit. 2, commonly used varistor have silicon pressure sensitive resistance and zno varistor, in which zinc oxide varistor used more widely, it is zinc oxide as the main raw material, add a variety of trace metal oxide, after mixing forming, sintering assembled a new ideal of over-voltage protection device, its conductive value changing with the change of the applied voltage which is nonlinear, people call it the varistor or surge absorber. Second, the main parameters of varistor term U1mA: 1, the nominal voltage or pressure sensitive voltage under the condition of dc voltage, current through the provisions of varistor, varistor voltage is called pressure-sensitive voltage varistor. General provisions, when the pressure sensitive resistance through the voltage of the dc 1 ma U1mA called pressure-sensitive voltage. For diameter of 5 mm or smaller size of varistor, with 0. 1 ma to nominal voltage measurement point, large diameter for low voltage products, also have to 20 ma to represent the nominal voltage. 2, test current I1mA: with pressure-sensitive voltage corresponding to the current known as the test current, usually test current regulation of dc 1 ma. 3, voltage ratio: pressure sensitive resistance through the provisions of the size of the current when the ratio of pressure drop and pressure sensitive dc voltage is called voltage ratio. 4, voltage temperature coefficient: in the specified temperature range and the provisions of the pulse current conditions, when the pressure sensitive resistance when the body temperature change 1 ℃, voltage relative percentage change called voltage temperature coefficient. 5, traffic: in a specified time interval and the number of times, places the standards stipulated by the current on the varistor waveform after shock, piezoresistive pressure sensitive voltage change rate is less than or equal to the value specified in the technical conditions, the flow capacity through the current value is called surge, referred to as 'flow. Within the prescribed time ( 8μs/20μs) Within the allowed through pulse current value. 90% of the pulse electric current from a big value to the value of time is 8 mu s, the peak duration of 20 mu s. 6, the voltage rate: pressure sensitive resistance before and after the impact test, the percentage of pressure-sensitive voltage relative changes called voltage change rate. Voltage rate = [formula is as follows: ( U1, U2) × The 100% type: U1, U2, respectively before and after the test voltage. 7, leakage current ( μA) : when the components on both ends of the voltage is equal to the electrical flow under the voltage on both ends 75%, varistor on known as leakage current through the dc current. 8, rated power P: the environment temperature of rules during the load power of the resistor is called power rating. 9, inherent capacitance C: stored in the varistor charge between the poles and the ratio of the applied voltage on the. Ten Uc and residual pressure: when the pressure sensitive resistance to flow through a pulse current, peak appeared on both ends of varistor voltage is called the residual pressure. 11, the compression ratio, pressure sensitive resistance of the residual pressure value and the ratio of pressure-sensitive voltage U1mA. Pressure sensitive resistance is not a general sense of resistance. It is formed by using insulation membrane separation metal oxide ( Such as zinc oxide) Particles, called MOV (abroad MetalOxideVaristor) , have very big resistance under low voltage, small leakage current; When higher voltage, pressure sensitive resistance of insulating film into a conductor, a slight increase in voltage, current rise sharply, similar to the voltage regulator tube breakdown characteristic, can withstand great instantaneous power. Varistor and often in switch power adapter at the input wire and wire, wire and between the center line, and inductors as surge and absorption peak voltage components. Working voltage is usually half the breakdown voltage. Is the main characteristic parameters Ub breakdown voltage and residual pressure than W eta and bear the loss of energy. 文章/ ymdzdzytdz。 HTML this paper label: an article on resistance pressure sensitive resistance: monolithic capacitor and the difference between patch capacitance next article: what is a common-mode inductor, the properties of the common-mode inductor
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