How to apply and select conventional aluminum electrolytic capacitors?

1. Advantages and disadvantages of aluminum electrolytic capacitors: Advantages: It has the significant advantages of easy access to large capacity and high withstand voltage, low cost, etc., and is commonly used in the input and output filter circuit of the power supply.

Disadvantages: Fear of high temperatures.

Because the electrolyte of aluminum electrolytic capacitors is in a liquid state, the core heating or high ambient temperature will cause the electrolyte to volatilize, and the long-term high temperature will cause the electrolyte to dry up and fail.

Figure 1 Schematic diagram of aluminum electrolytic capacitor failure 2. Application precautions for aluminum electrolysis in power supply circuits (1) Prevent halogen corrosion Aluminum electrolytic capacitors are very sensitive to chlorine and bromine, and if halogen-containing fluxes, cleaning agents, fixatives, and fumigants are used, halides may invade the capacitor through the sealing rubber plug, which is easy to cause capacitor anodic corrosion and accelerate capacitor failure after power-on.

Therefore, the halogen composition of the relevant sensitive formulations used in the production process must be strictly controlled.

2) Control and regular activation of the storage environment It is necessary to control the storage environment and time of the electrolytic capacitor, and regularly power on and empower it.

After aluminum electrolysis is stored in a high-temperature environment for a long time, the chemical reaction between the capacitor anodized film and the electrolyte will occur, resulting in a decrease in withstand voltage and an increase in leakage current.

When the power is suddenly turned on, the capacitor voltage is close to the rated voltage, which may cause overvoltage failure or excessive leakage current and overheating failure.

It is recommended to connect a 1k protection resistor in series, gradually pressurize to the rated voltage, and maintain it for about 1 hour, so that the anodized film of the capacitor can be repaired and the leakage current returns to the normal level.

3) Reasonable layout of the devices on the PCB to keep the aluminum electrolytic capacitor away from the heat source (4) According to the characteristics of the product, select the solid-state capacitor For example, in the application of low-voltage and high-current output, the aluminum solid-state capacitor is used.

Aluminum solid-state capacitors have a very low ESR and high ripple current tolerance, making them ideal for rectifier filtering applications with low voltage and high current.

Figure 2: Common electrolytic capacitor appearances and solid-state capacitor applications.

Some people say that in actual use, the capacitor withstand voltage value is taken to leave 80% margin, and some say that the value is twice the target voltage value. In fact, these views are not wrong, because everyone faces inconsistent items, inconsistent devices, and inconsistent sales of electronic products, which is essentially the inconsistent ripple characteristics of the circuit, so different margins are required. For example, if you use the place where your product is used, the power grid conditions are slight, and the ripple caused by it is relatively large, then you leave a larger margin, 2 times the value, and find the reliability; If your product has a good power grid environment and good ripple characteristics, then you can double the value, which also meets your product requirements; If the voltage is basically like a dry battery, ripple-free basically, then you can just go a little higher, right? However, it is important not to mention that the withstand voltage value should not be less than the peak voltage of the power supply or signal line, as this will cause damage to the capacitor.

About the use of aluminum electrolytic capacitors Next, Shandong Hongbao Electronics will introduce you to the use of aluminum electrolytic capacitors.

The use of aluminum electrolytic capacitors and their production process, precautions Aluminum electrolytic capacitors are made of aluminum cylinders as negative electrodes, which are filled with liquid electrolytes, and are called aluminum electrolytic capacitors.

A capacitor is an energy storage element that is used in circuits for tuning, filtering, coupling, bypassing, energy conversion, and time delay. Capacitors are often referred to as capacitors.

Types and uses of aluminum electrolytic capacitors.

1. According to the structure, it is divided into three categories: fixed capacitors, variable capacitors and trimmer capacitors.

2. Classification according to electrolyte: organic dielectric capacitors, inorganic dielectric slag containers, electrolytic capacitors and air dielectric capacitors, etc.

3. According to the application, it is divided into: high-frequency bypass, low-frequency bypass, filtering, tuning, high-frequency coupling, low-frequency coupling, and small capacitors.

4. According to the different manufacturing materials, it can be divided into: porcelain dielectric capacitors, polyester capacitors, electrolytic capacitors, etc.

5. High-frequency bypass: ceramic capacitors, mica capacitors, glass film capacitors, polyester capacitors, glass glaze capacitors.

6. Low-frequency bypass: paper dielectric Shen Sui Jing container, ceramic capacitor, aluminum electrolytic capacitor, polyester capacitor.

7. Filtering: aluminum electrolytic capacitors, paper dielectric capacitors, composite paper dielectric capacitors, liquid tantalum capacitors.

8. Tuning: ceramic capacitors, mica capacitors, glass film capacitors, polystyrene capacitors.

9. Low coupling: paper dielectric capacitors, ceramic capacitors, aluminum electrolytic capacitors, polyester capacitors, solid tantalum capacitors.

10. Small capacitors: metallized paper dielectric capacitors, ceramic capacitors, aluminum electrolytic capacitors, solid tantalum capacitors, glass.

Glaze capacitors, metallized polyester capacitors, mica capacitors.

Aluminum electrolytic capacitor is a common capacitor, and its application principles include the following:1Choose the right capacitance and voltage level.

The capacitance value and operating voltage of aluminum electrolytic capacitors need to be selected according to the actual needs to ensure that the required circuit requirements are met. 2.Avoid reverse polarity connections.

Due to the polarity of aluminum electrolytic capacitors, it is necessary to pay attention to the connection direction of the positive and negative electrodes during use to avoid damage to the components or the circuit does not work due to the reverse polarity connection. 3.Controls the temperature of the capacitor.

The lifetime of aluminum electrolytic capacitors is closely related to temperature, and when the ambient temperature is higher than the specified temperature, its service life will be greatly shortened. Therefore, it is necessary to control the temperature of the capacitor so that it can operate normally within the specified temperature range. 4.

Pay attention to the frequency response of the capacitor. The frequency response of aluminum electrolytic capacitors is poor, which has certain limitations on the transmission of high-frequency signals. Therefore, when using aluminum electrolytic capacitors, it is necessary to select the appropriate capacitor type or take other corresponding measures to compensate according to the specific application situation to achieve better results.

To sum up, the application principles of aluminum electrolytic capacitors mainly include selecting the appropriate electric volt balance capacity and lack of hand voltage level, avoiding reverse polarity connection, controlling the temperature of the capacitor, and paying attention to the frequency response of the capacitor.

What material are aluminum electrolytic capacitors made of? Aluminum electrolytic capacitors are composed of aluminum foil (positive and negative), lead wire (positive and negative), rubber stopper, electrolyte, aluminum shell, and bushing. Aluminum foil is a formed foil covered with alumina; The old Xinming lead is composed of an aluminum tongue with an aluminum sliding and an iron-tinned CP wire; The electrolyte is generally a glycol solution of ammonium of weak acid; There are many types of casing, including PET and PVC (banned, but it is not excluded that there are crimes committed against the wind) and so on.

The following are the common sizes of 400v aluminum electrolytic capacitors.

400v1uf size d*l mm) pants positive.

Size or 8*12mm or.

The ruler head is sensitive or 8*12mm

400V22UF size: 10*18mm or 10*25mm or 13*18mm or 13*20mm or 16*20mm

There are two main symbols for electrolytic capacitors; One is the circuit diagram symbol, and the other is the slag preparation PCB diagram symbol. The following figure is the symbol symbol of the electrolytic capacitor circuit diagram, the first of which is the polarized capacitor symbol without bishan, and the second is the polarized capacitor (electrolytic capacitor) symbol.

The figure below is the symbol symbol of the electrolytic capacitor in the PCB circuit board, where there is a shaded part on the left side corresponding to the negative pole of the electrolytic capacitor, and the other side has it"+"is the positive electrode; There are also some people who omit the right one"+"The two dots in the middle are the pads of the PCB.

Electrolytic capacitors are usually made of metal foil (aluminum-tantalum) as the positive electrode, and the insulating oxide layer of the metal foil (alumina-tantalum pentoxide) as the dielectric, and electrolytic capacitors are divided into aluminum electrolytic capacitors and tantalum electrolytic capacitors with their positive electrodes.

The negative electrode of an aluminum electrolytic capacitor consists of a thin paper film or electrolyte polymer immersed in an electrolyte liquid (liquid electrolyte); The negative electrode of tantalum electrolytic capacitors is usually manganese dioxide in the cavity of manganese. Since the electrolyte is used as the negative electrode (note the distinction from the dielectric), the electrolytic capacitor gets its name.

DC blocking: The function is to prevent DC from passing through and allowing AC to pass.

Bypass (decoupling): Provides a low-impedance path for certain components in parallel in an AC circuit.

The sawtooth wave after rectification is changed to a smooth pulsating wave, which is close to direct current. Energy storage: Storing electrical energy and releasing it when necessary.

1UF 100V,,, or more is a non-inductive CCB capacitor. The functions are as follows: DC isolation: The function is to prevent the DC from passing through and allowing the AC to pass.

Bypass (decoupling): Provides a low-impedance path for certain components in parallel in an AC circuit.

Coupling: Acts as a connection between two circuits that allows AC signals to pass through and be transmitted to the next level of circuitry. Filtering: Turning the rectified sawtooth wave into a smooth pulsating wave, close to DC.

Aluminum electrolytic capacitors.

It is made of an aluminum cylinder as the negative electrode, which is filled with a liquid electrolyte, and inserted into a curved aluminum strip to make the positive electrode. It also needs to be treated with DC voltage to form a layer of oxide film on the positive electrode sheet as a medium. It is characterized by large capacity, but large leakage, large error, poor stability, often used as AC bypass and filtering, and also used for signal coupling when the requirements are not high.

Electrolytic capacitors are divided into positive and negative electrodes, and cannot be reversed when used. There are positive and negative polarities, and when using them, the positive and negative poles should not be reversed.

Hello, there are many types of aluminum electrolytic capacitors and a wide range of functions Many places can be used in terms of functions: energizing, coupling, filtering, resistance, start-up and other functions can be asked here, thank you.

There's a sapphire capacitor here).

Filtering, bypassing, coupling, delay, etc.

The basic parameters of aluminum electrolytic capacitors mainly include voltage, capacitance, maximum operating temperature and life, leakage current and loss factor, and some aluminum electrolytic capacitors, such as aluminum electrolytic capacitors with tantalum capacitors for switching power supply output filtering, as well as rated ripple current, ESR and other parameters.

That's a lot

The main parameters are voltage, capacity, temperature resistance, life, volume, pitch, etc.

There's a sapphire capacitor here).