Patch capacitance selection guide and advantages and disadvantages Capacitance knowledge

by:Thermistor-Mov     2020-06-22
Patch capacitance selection guide and advantages and disadvantages of this article mainly introduced the advantages and disadvantages of tiles capacitors, this article about 1060 words, reading should be 11 minutes. Capacitor is basis of circuit components, aluminum electrolytic capacitors because of its cheap, large capacity are widely used. With the miniaturization of electronic products, electrolytic capacitor for big volume and ripple current fever caused by itself, gradually replaced by patch capacitance. With the development of technology, MLCC can do more and more to small volume, reached $0201, should the value also increased, has saved a space, restrain ripple, the advantages of prolonging life. But the ESR (MLCC The equivalent series resistance) The characteristics of small but have the opposite effect, because produce abnormal vibration and the resonance condition, therefore when the replacement need to be pay attention to. With the progress of technology, more than 10 ~ 100 u F high-capacity MLCC to realize the transition, thus available to the change of electrolytic capacitor. The life of the electrolytic capacitor for 10 years, but there is almost no elements will shorten the life of MLCC. Output capacitor, electrolytic capacitor has been replaced for MLCC using analog circuits, such as replacement of decoupling capacitor more and more. All kinds of large capacity of capacitor using the matters needing attention, because of their heating but will easily lead to a shorter lifespan capacitor's ESR electrolytic capacitor will change according to different frequency. Will be in a certain frequency capacitor ESR represented as R, ripple current are represented as I, is RI2 electric heat loss, so that the capacitor his fever. Electrolytic capacitor has the characteristics of large capacity, but due to its high ESR, thus ripple current lead to excessive heat is its shortcomings. Capacitor acceptable limit called allow ripple current ripple current. If use more than allow will shorten the life of the capacitor ripple current. An ideal capacitor is only static capacity of components, but in reality, it also has a composition of resistance and inductance components due to the electrode. Circuit diagram of can't identify the resistance of the component, called the ESR ( The equivalent series resistance) , inductance components called ESL ( Equivalent series inductance) 。 Although direct current is a certain voltage and the current which flows in one direction, but overlap with noise current in power supply circuit of the dc current and other kinds of communication components. For example, through to the commercial ac rectifier ( Full-wave rectifier) After get the dc current cycle for the commercial alternating current (ac) 2 times are contained in the microwave, Corrugated) Pulsating current. At the same time, the switch mode DC - DC converter, DC voltage overlap with pulsating current switching cycle. These are called ripple current. Aluminum electrolytic capacitor electrostatic capacity is big, the price is low, so widely used in electronic equipment, but its service life, so need to pay special attention to when using. The service life of aluminum electrolytic capacitor for 10 years or so commonly. This is due to the electrolyte (dry Evaporation) Results in the decrease of electrostatic capacity (caused by Capacity loss) 。 The disappearance of the electrolyte and temperature related, the basic meet is called the 'law of Arrhenius' theory of chemical reaction rate. The law says, if use temperature 10 ℃, life becomes the original half, if falling 10 ℃ life will become 2 times, so the laws of 10 ℃ for 2 times. Therefore, the current ripple caused his fever is larger under the conditions of use, life will be further reduced. At the same time, the electrolyte dry also can make the ESR. Dc voltage and ripple overlap, need to pay attention to peak voltage ripple does not exceed the rated voltage ( Pressure) 。 Power supply circuit used about 3 times rated voltage for the input voltage of capacitor. Article/tpdrdxxznj. HTML this paper label: SMD capacitor SMD capacitors on the selection guide and advantages and disadvantages of an article: how to choose the suitable type magnetic bead model next article: how to judge start capacitor
Custom message
Chat Online 编辑模式下无法使用
Chat Online inputting...