Capacitor principle Capacitors in series can be separated through the cross, parallel can be filtered. A capacitor is just two disconnected metal plates. The role of capacitors in electronic circuits is generally summarized as: AC, DC.
Capacitors usually play the electrical functions of filtering, bypass, coupling, decoupling, and conversion, and are an essential part of electronic circuits.
The filter circuit passes the pulse to the ground, not to the output.
It is because of the communication that the AC component can be led to the ground and the DC component can be retained. Under normal circumstances, the role of the electrolytic capacitor is to filter out the low-frequency signal in the current, but even the low-frequency signal, its frequency is divided into several orders of magnitude.
Therefore, in order to be suitable for use at different frequencies, electrolytic capacitors are also divided into high-frequency capacitors and low-frequency capacitors (here the high frequency is relative).
The low-frequency filter capacitor is mainly used for the filter after the mains filter or transformer rectification, and its working frequency is the same as that of the mains at 50Hz; The high-frequency filter capacitor mainly works in the filtering after the switching power supply rectification, and its operating frequency is thousands of Hz to tens of thousands of Hz.
When we use the low-frequency filter capacitor in the high-frequency circuit, because the high-frequency characteristic of the low-frequency filter capacitor is not good, it is larger in the high-frequency charge and discharge, and the equivalent inductance is higher.
Therefore, in use, large heat will be generated due to the frequent polarization of the electrolyte.
The higher temperature will vaporize the electrolyte inside the capacitor, and the pressure inside the capacitor will rise, eventually leading to the bulge and burst of the capacitor. In fact, it is mainly the working principle of charge and discharge. In fact, the capacitor is equivalent to a reservoir, so that the fluctuation of the water becomes very smooth, the role of the electrolytic capacitor has a filter, generally used in the back of the rectification bridge.
You can look at whether the capacitor is connected or connected in the loop, the parallel is the rate of the high frequency, the series is the rate of the low frequency. And step-down capacitors. There is the role of separating straight, generally for protection! What are the roles of series and parallel capacitors in a circuit?
The role of the capacitor is to store and release charge, and can play a role in separating through communication, filtering, and oscillating capacitors in the circuit: Such as series use is generally used as AC signal isolation, such as audio power amplifier, video amplifier, etc., such as parallel use is generally used as filter, For example, the noise removal in the power supply and signal processing circuit can be formed in parallel with the inductor or other chips, such as wireless signal transmission, reception, modulation, demodulation and other capacitors can be increased in parallel, and reduced in series.
For example, there is no large capacitor on hand, only a small one can be used together, and on the contrary, there is no small one can be used with a large string.
In the integrated circuit, very large scale integrated circuit has been popular today, capacitors as a discrete passive component is still widely used in a variety of functional circuits, its important role in the circuit can be seen.
As an energy storage component is also an important application field of capacitors, compared with batteries and other energy storage components, capacitors can be instantaneous charge and discharge, and the charge and discharge current is basically unrestricted, can provide high-power instantaneous pulse current for welding machines, flash lights and other equipment
The basic working principle of capacitors is charging and discharging, and of course rectification, oscillation and other functions. In addition, the structure of the capacitor is very simple, mainly composed of two positive and negative electrodes and an insulating medium sandwiched in the middle, so the type of capacitor is mainly determined by the electrode and the insulating medium. There are many uses of capacitors, mainly as follows:
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1. Dc isolation: The function is to prevent the DC through and let the AC through.
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2. Bypass (decoupling) : Provides a low-impedance path for certain parallel components in an AC circuit.
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3. Coupling: Acts as a connection between two circuits, allowing AC signals to pass through and be transmitted to the next level circuit
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4. Filtering: This is very important for DIY, the capacitors on the graphics card are basically this role.
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5. Temperature compensation: For the impact of the insufficient adaptability of other components to the temperature, and compensation to improve the stability of the circuit.
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6. Timing: The capacitor is used in conjunction with the resistor to determine the time constant of the circuit.
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Seven. Tuning: Systematic tuning of frequency-dependent circuits, such as cell phones, radios, and television sets.
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8. Rectifier: Turning on or off a semi-closed conductor switch element at a predetermined time.
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9. Energy storage: Storing electrical energy for release when it is needed. Such as camera flash, heating equipment, etc.