What is the role and application of capacitors in electrical appliances?

2021-03-29

A capacitor is an energy storage element, which can store a certain amount of charge in a unit of time and release it slowly.

Using this characteristic of capacitors, capacitors are mainly used in electrical circuits.

Filtering and resonance.

Two functions.

There are many kinds of capacitors that we usually see, such as electrolytic capacitors, ceramic capacitors, monolithic capacitors, film capacitors, paper capacitors and so on. Its working principle is the same-Charge and discharge process!

Theoretically, the capacitance is only the capacitance value but not the resistance value under the measurement of the multimeter. 〈

Once the resistance value appears, it means that it has broken down and is broken.

〉According to the different types of capacitors, the working characteristics are also different, so the working occasions are different.

For example, electrolytic capacitors are mostly used for power supply filtering to improve the stability of the power supply. 〈

Of course, it is not so absolute. It is not that electrolytic capacitors cannot participate in the function of circuit resonance at all.

〉For circuit resonance, these are small-capacity stepless capacitors 〈

Most electrolytic capacitors have polarity, of course, there are also special non-polar electrolytic capacitors that are mostly used for motor starting.

〉The linear index of this type of capacitor is very good, and it is generally difficult to damage. So basically there is no doubt that these capacitors in the circuit will be damaged.

Due to technological improvements, the degree of circuit integration has increased. Now more circuits are integrated with more SMD originals, and SMD capacitors with ceramics as the dielectric have been used more in recent years. Ceramic capacitors are more stable and linear, and the damage rate is not high. However, some of the patch content used in the filtering function of small power supplies may be short-circuited due to overvoltage. We can generally detect it by burning the machine.

The damage degree of capacitors used in power supply filtering is very high, especially those dedicated power supplies that need to provide large current for long-term work, such as power supplies for televisions, air conditioners, and computers. These capacitors are electrolytic capacitors with a large capacity. If they are damaged, it can be easily seen. We call them "pregnant", which means they are bulging. Once the capacitor bulge appears in the circuit, it is best to change it all at once, because even if the capacitor is not bulged, the electrolyte may have dried up, and the capacity will be greatly reduced! The possibility of electrolytic capacitor short circuit is not high. This has not happened yet in my impression!

The other is the starting capacitor of the motor, most of which are electrolytic stepless capacitors. Of course, small motors also use paper capacitors or polyester capacitors, and the functions are the same! This type of capacitor is easy to burn out and fail, and there are not many short-circuits.

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