Application of intelligent capacitor

All kinds of capacitors are needed in electronic construction, which play different roles in circuit bisection.

Similar to resistor, it is usually referred to as capacitance, which is indicated by letter C. In other words, a capacitor is a container for storing electric charge. Although there are many kinds of capacitors, their basic layout and principles are the same. Two pieces of metal which are very close to each other are separated by a certain material (solid, gas or liquid) to form a capacitor. Two pieces of metal are called plates, and the central material is called medium. Capacitors can also be divided into two types: firm capacity and variable capacity. However, it is common to see solid capacity capacitors, most of which are electrolytic capacitors and ceramic chip capacitors. Different capacitors have the same ability to store charge. It is stipulated that the amount of charge stored when the capacitor is applied with 1 V DC voltage is called the capacitance of the capacitor. The basic unit of capacitance is farad (f). But in reality, farad is a very infrequently used unit. Because the capacity of capacitor is often much smaller than 1 farad, micro method (μ f), nano method (NF), skin method (PF) (also known as micro method) are often used. Their relationship is: 1 farad (f) = 1000000 micro method (μ f), 1 micro method (μ f) = 1000 nano method (NF) = 1000000 skin method (PF) In electronic circuit, capacitance is used to insulate DC through exchange, and also to store and release electric charge to act as filter and output pulse signal smoothly.

  Small capacitance, usually used in high frequency circuits, such as radio, transmitter and oscillator. Large capacity capacitors are often used for filtering and storing charges. And there is another characteristic. The capacitors above 1 μ f are all electrolytic capacitors, while the capacitors below 1 μ f are mostly ceramic chip capacitors. Of course, there are other capacitors, such as monolith capacitors, polyester capacitors, mica capacitors with small capacity, etc. The electrolytic capacitor has an aluminum shell, which is filled with electrolyte, and leads out two electrodes, which are positive (+) and negative (-) poles. They are different from other capacitors. Their polarity in the circuit cannot be connected wrongly, while other capacitors have no polarity. Separate the two electrodes of the capacitor from the positive and negative electrodes of the power supply. After a while, even if the power supply is disconnected, there will still be residual voltage between the two pins (after learning the next tutorial, you can use a multimeter to check). We say that the capacitor has stored the charge. A voltage is set up between the capacitor plates to store electric energy. This process is called capacitor charging. There is a certain voltage at both ends of the charged capacitor. The process of discharging the stored charge to the circuit is called discharge of capacitor. As an example in real life, we can see that after unplugging the commercial rectifier power supply, the light-emitting diode on it will continue to light for a while, and then gradually go out, because the capacitor in it stores the electric energy in advance and then releases it. Of course, this capacitor was originally used for filtering. As for the capacitance filtering, I don't know if you have the resume of the useless rectifier power supply to listen to the walkman. The common low-quality power supply is because the manufacturer makes use of the filter capacitance with small capacity due to the cost saving consideration, forming a buzz in the headset. At this time, we can connect a large capacity electrolytic capacitor (1000 μ F, pay attention to the positive electrode), which can improve the results. If you want to build hifi sound, you need to use at least 10 thousand Micromethods of capacitors to filter. The larger the filtering capacitance is, the closer the output voltage waveform is to DC, and the energy storage of the large capacitance is affected, so that when the sudden big signal arrives, the circuit has enough energy to convert into weak and powerful audio output.

  At this time, the influence of large capacitance is a bit like a reservoir, which makes the originally turbulent water flow smoothly output and can guarantee the supply of a large amount of downstream water. In electronic circuit, as long as the capacitor is in the process of charging, there will be current flow. After the charging process is completed, the capacitor cannot pass through DC, and plays a role of "DC isolation" in the circuit. In the circuit, capacitor is often used as coupling, bypass, filtering, etc. Then why can switching electricity go through capacitors? Let's first look at the characteristics of switching electricity. Not only is the purpose of exchange changing, but its size is also changing according to discipline. When the capacitor is connected to the switching power supply, the capacitor will continuously charge and discharge, and the charging current and discharge current will flow in the circuit which are different from the switching electricity transformation discipline. There are many problems in the selection of capacitors. First of all, pressure resistance. When the voltage applied to both ends of a capacitor crosses its rated voltage, the capacitor will be broken down. The withstand voltage of common electrolytic capacitor is 6.3V, 10V, 16V, 25V, 50V, etc.