As we all know, capacitors play a very important role in electronic equipment. As one of the most widely used electronic components, capacitors have many types.Solid capacitors are a type of capacitor distinguished by dielectric materials, and the effects of solid capacitors are also very wide. Today, let’s take a look at what solid capacitors are and what their effects are.
1. What is a solid capacitor?
The full name of solid capacitor is: solid aluminum electrolytic capacitor .
The biggest difference between it and general capacitors (i.e., liquid aluminum electrolytic capacitors) is the use of different dielectric materials. The dielectric material of liquid aluminum capacitors is electrolyte, while the dielectric material of solid capacitors is conductive polymer materials.
2. The role of solid capacitors
Solid capacitors are also a type of capacitor, so the role of solid capacitors is not very different from that of general capacitors. It's just that solid capacitors have good stability, long life, low ESR (equivalent series resistance) and high rated ripple current compared to general capacitors.
The main functions of solid capacitors are as follows:
1) Remove lotus roots
Remove the lotus root, also known as lotus root removal. From a circuit perspective, it can always be distinguished as a driven source and a driven load. If the load capacitance is relatively large, the driving circuit must charge and discharge the capacitor to complete the signal transition. When the rising edge is relatively steep, the current is relatively large, so the driving current will absorb a large power supply current. Since the circuit The inductance and resistance (especially the inductance on the chip pins will cause rebound), this current is actually a kind of noise compared to normal conditions, which will affect the normal operation of the front stage. This is coupling.
The decoupling capacitor functions as a battery, meeting the changes in the drive circuit current and preventing mutual coupling interference.
2) Filtering
Theoretically (that is, assuming that the capacitor is a pure capacitor), the larger the capacitor, the smaller the impedance and the higher the passing frequency. But in fact, most capacitors exceeding 1uF are electrolytic capacitors, which have a large inductance component, so the impedance will increase when the frequency is high. Sometimes you will see an electrolytic capacitor with a large capacitance connected in parallel with a small capacitor. At this time, the large capacitor passes low frequency and the small capacitor passes high frequency. The function of the capacitor is to pass high frequencies and resist low frequencies, and to pass high frequencies and resist low frequencies. The larger the capacitance, the easier it is for low frequencies to pass, and the larger the capacitance, the easier it is for high frequencies to pass. Specifically used in filtering, large capacitors (1000uF) filter low frequencies, and small capacitors (20pF) filter high frequencies.
Some netizens once compared filter capacitors to "ponds". Because the voltage across the capacitor will not change suddenly, it can be seen that the higher the frequency of the signal, the greater the attenuation. It can be said vividly that the capacitor is like a pond, and the amount of water will not change due to the addition or evaporation of a few drops of water. It converts changes in voltage into changes in current. The higher the frequency, the greater the peak current, and then buffers the voltage. Filtering is the process of charging and discharging.
3) Energy storage
The energy storage capacitor collects charges through the rectifier and transmits the stored energy to the output end of the power supply through the converter leads. Aluminum electrolytic capacitors with a voltage rating of 40 to 450VDC and a capacitance value of 220 to 150 000uF are more commonly used. Depending on the power requirements, equipment is sometimes connected in series, parallel or a combination thereof. For power supplies with power levels exceeding 10KW, larger can-shaped screw terminal capacitors are usually used.
The above three are the most common effects of solid capacitors.
Although capacitors can be divided into various types of capacitors according to different classification standards, their essence is still a capacitor. Therefore, the role of solid capacitors basically also has the common functions of capacitors. If you want to know more information about the role of solid capacitors, please pay attention to our official website!
