What is an aluminum electrolytic capacitor?
What is an aluminum electrolytic capacitor?
The aluminum electrolytic capacitor is made of an aluminum cylinder as a negative electrode, which is contained with liquid electrolyte and inserted into a curved aluminum belt to make a positive electrode. It also needs to be treated with DC voltage to form an oxide film on the positive electrode as a medium. It is characterized by large capacity, but large leakage, poor stability, positive and negative polarity, which is suitable for power filtering or low-frequency circuits. When using, the positive and negative poles should not be reversed.
What is the working principle of aluminum electrolytic capacitor?
The working principle of aluminum electrolytic capacitor is based on the oxide film formed on the surface of anode aluminum foil as a dielectric. This capacitor is composed of anode aluminum foil, electrolyte, electrolytic paper (or electrolyte polymer) and cathode aluminum foil. The anode aluminum foil forms a very thin oxide film through electrolytic oxidation (chemical). This oxide film has the characteristics of rectification, which makes the capacitor polar. Electrolytes and electrolytic paper (or electrolyte polymers) are filled between the anode and the cathode, which plays the role of conducting electricity and storing charge.
When a positive voltage is applied at both ends of the aluminum electrolytic capacitor, the negative ions gather near the dielectric aluminum trioxide, and the positive ions gather near the cathode aluminum foil, showing the characteristics of capacitance. However, if a reverse voltage is applied, the positive ions will gather near the dielectric aluminum trioxide, causing the hydrogen ions to pass through the dielectric and eventually convert into hydrogen. The expansion force causes the dielectric to fall off and cause the capacitor to fail. Therefore, the aluminum electrolytic capacitor cannot withstand the reverse voltage, and there may be flatulence, heat and even explosion after reverse connection.
What are the types of aluminum electrolytic capacitors?
According to the form, it can be divided into:
Solid aluminum electrolytic capacitor is an electronic component that stores charge and produces a capacitance effect by forming a layer of alumina oxide film on aluminum foil. It is characterized by large capacity, small size, long service life and wide operating temperature range, and is widely used in electronic circuits. Common models are:
1. SMD aluminum electrolytic capacitor: SMD aluminum electrolytic capacitor is a surface-mount aluminum electrolytic capacitor with small size and light weight. It is suitable for situations with limited space on electronic circuit boards, such as mobile phones, computers and other electronic products.2. Axial aluminum electrolytic capacitor: The axial aluminum electrolytic capacitor has a large size, similar to ordinary electronic components, and is suitable for general electronic circuits.
Liquid aluminum electrolytic capacitor is a kind of capacitor containing liquid electrolyte. It uses aluminum foil as the polar plate and grain as the electrolyte. It is usually used in high-end electronic equipment such as high-power power supply filters, inverters and frequency converters. Common models are:
1. Ordinary liquid aluminum electrolytic capacitor: Ordinary liquid aluminum electrolytic capacitor has large capacity, good frequency response and long service life, and is suitable for general circuits.
2. High-frequency liquid aluminum electrolytic capacitors: High-frequency liquid aluminum electrolytic capacitors can withstand high working frequencies and are suitable for high-frequency circuits.
In addition, there are consumer aluminum electrolytic capacitors and industrial-grade aluminum electrolytic capacitors.
What are the advantages and disadvantages of aluminum electrolytic capacitors?
Advantages of aluminum electrolytic capacitors1. Cheap price: The cost of aluminum electrolytic capacitors is relatively low, which is easier to obtain than other types of capacitors.
2. Large capacity: The capacity of aluminum electrolytic capacitors is much larger than that of other types of capacitors, which is suitable for circuit design that requires large capacity.
3. Good stability: The aluminum electrolytic capacitor has good stability, low temperature drift and working voltage drift, so it can adapt to various complex working environments.
1. Short service life: The service life of aluminum electrolytic capacitors is relatively short, generally around 1-5 years. With the extension of the use time, the capacitance value will change and may lead to leakage and other phenomena.
2. Low mechanical strength: The mechanical strength of aluminum electrolytic capacitors is relatively low and is easily damaged by external force induction.
3. Poor frequency characteristics: the response of aluminum electrolytic capacitors to frequency is slow, and it is difficult to adapt to the working state of high frequency and high current.
What are aluminum electrolytic capacitors used for?
The main functions of aluminum electrolytic capacitors include:1. Smooth power supply: Aluminum electrolytic capacitor can smooth the DC voltage fluctuation in the power supply and stabilize the power supply.
2. Filter function: Aluminum electrolytic capacitor can filter out high-frequency noise in the power supply and improve the signal quality of the circuit.
3. Stable current: Aluminum electrolytic capacitors can provide stable current and stabilize the working state of the circuit.
4.Electric charge storage: Aluminum electrolytic capacitors can store charges for releasing electrical energy and compensating the circuit.
What affect the life of aluminum electrolytic capacitor?
The life of aluminum electrolytic capacitors is usually measured by working hours, not by specific years. The life of an aluminum electrolytic capacitor depends on its use environment, working temperature, working voltage, capacitor load and other factors.Generally speaking, the life of aluminum electrolytic capacitors is between thousands and tens of thousands of working hours. High-quality aluminum electrolytic capacitors can achieve a longer life, while those with low quality or overload may have a shorter life.
In addition, the life of aluminum electrolytic capacitors is also related to its use and maintenance. For example, if the capacitor is within the rated voltage and temperature range and is properly protected and used, it will have a longer life.
What is the application of aluminum electrolytic capacitors?
Aluminum electrolytic capacitors have the following applications:1. Power filter
Aluminum electrolytic capacitors can be used as power filter capacitors, which can be used to stabilize the DC power supply, reduce voltage fluctuations and ripple voltage, and ensure the normal operation of the circuit. In general, the capacity of the power filter capacitor is large, and it is necessary to choose an aluminum electrolytic capacitor with high voltage capacity.
Aluminum electrolytic capacitor is one of the important components in audio amplifiers and is generally used for DC coupling and electrolytic coupling circuits. In the audio amplifier, the aluminum electrolytic capacitor can separate the audio signal from the DC bias voltage to improve the sound quality.
Aluminum electrolytic capacitors can be used as input and output capacitors in switching power supplies. At the input end, the aluminum electrolytic capacitor can play the role of filtering and reduce the switching noise and electromagnetic interference of the switching power supply. At the output end, the aluminum electrolytic capacitor can play a voltage stabilization role to ensure the stability of the output voltage.
Aluminum electrolytic capacitors are widely used on computer motherboards to stabilize voltage and protect other devices from voltage fluctuations.
In the distribution of communication equipment, aluminum electrolytic capacitors are often used to stabilize DC voltage, eliminate harmonics, and improve the performance of circuits. For example, it is widely used in mobile phones, tablets, switch circuits, etc.
What is the shelf life of aluminum electrolytic capacitors?
In general, the shelf life of aluminum electrolytic capacitors is 2-3 years, but the specific shelf life will also be affected by factors such as storage and use conditions.I. Effect of storage conditions on the shelf life of aluminum electrolytic capacitors
During the storage process of aluminum electrolytic capacitors, if the conditions are not appropriate, it is easy to cause the capacitor to fail. The following are several factors to pay attention to when storing aluminum electrolytic capacitors:
1. Temperature: Aluminum electrolytic capacitors should be stored at room temperature to avoid prolonged exposure to extreme high temperature or low temperature environment, otherwise the failure of aluminum electrolytic capacitors will be accelerated.
2. Humidity: Aluminum electrolytic capacitors should be stored in a dry environment to avoid moisture or too much moisture, otherwise it will reduce the working efficiency of aluminum electrolytic capacitors.
3. Light: Aluminum electrolytic capacitors should be stored in a dark place to avoid exposure to sunlight for a long time, otherwise it will affect their working efficiency.
4. Packaging: Before storage, the aluminum electrolytic capacitor should be put into an anti-static bag and try to avoid vibration and friction.
Improper storage conditions will accelerate the loss of aluminum electrolytic capacitors and shorten their service life, so it must be noted when storing.
In addition to storage conditions, the following factors should also be paid attention to in the use of aluminum electrolytic capacitors:
1. Voltage: Aluminum electrolytic capacitors should be used below their rated voltage to avoid failure caused by high voltage.
2. Temperature: When using aluminum electrolytic capacitors, you should also avoid being exposed to too high or too low temperature environment for a long time.
3. Environment: When using aluminum electrolytic capacitors, pay attention to avoid external forces such as strong vibration and vibration.
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