What is a capacitor
The ratio of the charged quantity Q of a capacitor to the voltage U between the two poles of the capacitor is called the capacitance of the capacitor.
In circuit science, the ability of a capacitor to store charges given a potential difference is called capacitance, labeled as C. Using the International System of Units, the unit of capacitance is farad, marked as F.
The symbol for capacitor is C
C= εS/d = εS/4πkd = Q/U
Unit and conversion of capacitor:
In the International System of Units, the unit of capacitance is Farad, abbreviated as Farad, with the symbol F. Due to the large unit of Farad, commonly used units of capacitance include milliamperes (mF) and microfarads（ μ F) The conversion relationship between nF, pF, etc. is:
1（F）= 10^3（mF）=10^6（μF）=10^9（nF）=10^12（pF）=10^15fF
The role of capacitors in circuits
Bypass
Bypass capacitors are energy storage devices that provide energy to local devices, which can homogenize the output of the voltage regulator and reduce load demand. Just like a small rechargeable battery, the bypass capacitor can be charged and discharged into the device. To minimize impedance, the bypass capacitor should be as close as possible to the power supply pin and ground pin of the load device. This can effectively prevent ground potential rise and noise caused by excessive input values. The ground potential is the voltage drop when the ground connection passes through a large current burr.
Decoupling
Decoupling, also known as decoupling. From a circuit perspective, it is always possible to distinguish between the source of the drive and the load being driven. If the load capacitance is relatively large, the driving circuit needs to charge and discharge the capacitance in order to complete the signal jump. When the rising edge is steep, the current is relatively high, so the driving current will absorb a large amount of power current. Due to the inductance in the circuit, the resistance (especially the inductance on the chip pins) will rebound, which is actually a type of noise compared to normal conditions, It will affect the normal operation of the previous stage, which is called "coupling".
Decoupling capacitors act as a "battery" to meet the changes in driving circuit current, avoid mutual coupling interference, and further reduce the high-frequency interference impedance between the power supply and reference ground in the circuit.
Combining bypass capacitors with decoupling capacitors will be easier to understand. The bypass capacitor is actually decoupled, but it generally refers to high-frequency bypass, which provides a low impedance discharge path for high-frequency switching noise. The high-frequency bypass capacitor is generally relatively small, and is generally taken as 0.1 based on the resonant frequency μ F. 0.01 μ F, etc; The capacity of decoupling capacitors is generally large, possibly 10 μ F or greater, determined based on the distributed parameters in the circuit and the magnitude of changes in driving current. Bypass is to filter out the interference in the input signal, while decoupling is to filter out the interference in the output signal, preventing the interference signal from returning to the power source. This is their fundamental difference.
Filtering
In theory (assuming that the capacitance is pure), the larger the capacitance, the smaller the impedance, and the higher the frequency of passage. But in fact, more than 1μF capacitors are mostly electrolytic capacitors, have a large inductance component, so the impedance will increase after high frequency. Sometimes you may see a large electrolytic capacitor connected in parallel with a small capacitor, where the large capacitor filters out low frequencies and the small capacitor filters out high frequencies. The function of a capacitor is to pass AC and DC, and to pass high-frequency and low-frequency. The larger the capacitance, the easier it is to pass through high frequencies. Specifically used in filtering, large capacitors (1000 μ F) Filter low frequency, small capacitance (20pF) filter high frequency. Some netizens once vividly compared the filtering capacitor to a "pond". Due to the fact that the voltage at both ends of the capacitor does not suddenly change, it can be seen that the higher the signal frequency, the greater the attenuation. It can be vividly said that the capacitor is like a pond, without any changes in water volume caused by the addition or evaporation of a few drops of water. It converts changes in voltage into changes in current, and the higher the frequency, the greater the peak current, thereby buffering the voltage. Filtering is the process of charging and discharging.
Stored energy
Energy storage capacitors collect charges through rectifiers and transmit the stored energy to the output of the power supply through converter leads. The voltage rating is 40-450VDC, and the capacitance value is 220-150 000μF Aluminum electrolytic capacitors between F are commonly used. According to different power supply requirements, devices may sometimes be in series, parallel, or their combination. For power supplies with power levels exceeding 10KW, larger can shaped spiral terminal capacitors are usually used.
Series of UF Capacitors
UF Capacitors was established since 1995, as one of the professional China capacitors manufacturer and China capacitors factory, we are strong in complete management, strict quality control system, and excellent sales service. We mainly produce and supply Chip MLCC Capacitors, Tantalum Capacitors, Polymer Capacitors, SMD Electrolytic Capacitors, X1Y2 X1Y1 X2 Safety Capacitors, DC Link Film Capacitors. In our factory, we have reliability test lab and UL test lab which allow us to do various tests inside of our own factory. Our factory keep regular stocks for chip MLCC and tantalum capacitors. For other capacitors, our normal lead time is 4 weeks. With fast delivery time, competitive prices, high quality commitment, customers can use our capacitors to replace Murata Capacitors, TDK Capacitors, Vishay Capacitors, Kemet Capacitors, AVX capacitors, Panasonic capacitors, Nichicon capacitors, Epcos capacitors and so on. Recent years, many capacitors are in shortage, could you please send us emails and RFQ. UF Capacitors can help you for cost down and solve your shortage problem.
The following is an introduction to UF Capacitors' ceramic capacitors, aluminum capacitors, and tantalum capacitors
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High frequency products |
Consumer Products, Laptops, |
Civil use, |
How to Obtain a Quote from UF Capacitors?
You can easily send an email to lily@ufcapacitors.com, the engineering and sales team in UF Capacitors will help you select the correct polymer aluminum capacitors.
For more details, pls visit our website: www.ufcapacitors.com
