Chip electrolytic capacitor characteristics and precautions for use

With the development of the times, electronic technology has reduced the demand for miniaturization and chipping of electrolytic capacitors, the rise of workers' wages, and the loss of population. In recent years, in order to solve these problems, enterprises have been using economical transformation to replace labor with machines. The application of chip electrolytic capacitors is also showing an increasing trend. In the future, surface mount aluminum electrolytic capacitors will eventually replace traditional plug-in electrolytic capacitors in terms of both quantity and amount.

At present, although the price of the chip-type electrolytic capacitor is higher than that of the conventional plug-in electrolytic capacitor, due to the increase in market demand, the production tends to be large-scale, and the price is decreasing year by year. In the three years from 2012 to 2001, the average unit price of products dropped by 20~30%.

Application of SMD Aluminum Electrolytic Capacitors:

SMD aluminum electrolytic capacitors play the role of filtering, coupling, DC blocking and energy storage in the circuit. They are widely used in various household appliances, computers, mobile communications, automotive electronics, smart grid, aerospace, rail transit and other fields. One of the main components that are indispensable in electronic equipment.

SMD aluminum electrolytic capacitor characteristics:

1. Wide operating temperature range,

2. Suitable for high density surface assembly SMD,

3. Suitable for reflow soldering,

4. Stable performance and high reliability.

SMD aluminum electrolytic capacitor reflow soldering should pay attention to which

(1). Infrared and hot air reflow soldering should be used, and vapor phase heating reflow soldering should not be used;

(2). It is recommended that reflow soldering be performed only once. If the number of reflow soldering needs two times, it must be separated by more than 30 minutes;

(3). Lead-free reflow soldering, please meet the following conditions:

a). The preheating time from 150 ° C to 200 ° C is within 180 seconds;

b) .The soldering time of the capacitor top temperature exceeding 217 ° C does not exceed tL seconds;

c). The peak temperature of the top of the capacitor does not exceed Tp ° C, and the actual peak temperature in the range of 5 ° C does not exceed tp seconds

Precautions for the use of SMD aluminum electrolytic capacitors:

A) Circuit design

1). Fully consider the capacitor use and installation conditions within the scope of the Huahui product target

2). The operating temperature and applied ripple current should be within the specified range of Huahui product targets.

3). When designing the circuit, you should select the product that meets the life requirements.

4). Aluminum electrolytic capacitors are polar and should not be supplied with reverse voltage or AC voltage. For circuits where long reverse voltages may occur, bipolar capacitors should be selected. Note: Even bipolar capacitors cannot be used directly in pure AC circuits.

5). For circuits that require fast and frequent charge and discharge, aluminum electrolytic capacitors should not be used, but specially designed capacitors with long life should be selected.

6) .Should not use overload voltage

1. The peak voltage after superposition of DC voltage and ripple voltage should not exceed the rated working voltage

2. If more than two capacitors are connected in series, make sure that the applied voltage is lower than the rated value, and connect a balancing resistor in parallel so that the applied voltage of each capacitor is equal.

7). Capacitors cannot be used in the following environmental conditions:

(a) .The capacitor is exposed to water (including concentrate), brine or oil.

(b). There are toxic gases such as hydrogen sulfide, sulfurous acid, nitrous acid, chlorine, bromine, methyl bromide and ammonia in the surrounding environment.

(c) .Ozone, ultraviolet light and radiation in the surrounding environment.

8). Electrolyte The main chemical solvent and electrolytic paper are inflammable and the electrolyte is conductive. When the electrolyte comes into contact with the PC board, it may corrode the wiring on the PC board or cause a short circuit, resulting in smoke or fire. Therefore there should be no lines at the lower end of the capacitor seal.

9). When designing the circuit board, make sure that the heating components are not close to the other side of the aluminum electrolytic capacitor or PC board, and avoid it just below the capacitor.

10) .When designing a circuit board, it should be considered that the electrical performance of the capacitor may vary with temperature and frequency.

11). When more than two capacitors are connected in parallel, the current balance through these capacitors should be considered.

12). When installing a capacitor on a double-sided board, the capacitor should be installed away from the excess substrate holes and vias.

B). Installation

1) .Once the capacitor has been installed and loaded, do not attempt to use it for other boards or other purposes.

2). Capacitors that have been stored for more than 2 years may have increased leakage current. If the leakage current increases, use a 1KΩ resistor for charging.

3). Before installing the container on the PC board, please confirm its specifications and polarity.

4). Do not drop the capacitor on the ground, or use a capacitor that is dropped on the ground.

5). Do not damage the capacitor during installation.

6). Please pay attention to the mechanical impact of the tip of the placement machine, the product inspection fixture or the alignment device on the capacitor.

7) .Reflow soldering

1 .Please observe the reflow conditions in the Huahui product target.

2. When using infrared heating, please pay attention to the degree of heating, because the infrared absorption rate will vary with the color and size of the capacitor.

8). After soldering the capacitor to the PC board, do not tilt or twist the capacitor.

9) .Do not hold the soldered capacitor to move the PC board.

10) .Do not allow anything to come into contact with the soldered capacitor. If the PC board is stacked and stored, make sure that the PC board or other components do not touch the capacitor.

11). Solder capacitors should not be affected by heat radiation from any soldered PC board or other components.

12). Cleaning:

1. Do not clean the capacitor with a halogenated cleaning agent.

2. push cleaning method:

Use range: any type and specification

Cleaning method: The cleaning time of soaking, ultrasonic or other methods should be within 2 minutes. The cleaning agent temperature should be below 40 °C. After cleaning, the capacitor should be blown with the PC board for a minimum of 10 minutes with hot air. The hot air temperature should be lower than the capacitor operating temperature. If it is not sufficiently dried after washing, it may cause poor appearance, such as swelling of the seat plate.

3 . Avoid using ozone depleting detergents to protect the environment.

C). After installation

1) .Do not touch the positive and negative terminals of the capacitor directly with your hands.

2) .Do not connect the conductor between the positive and negative electrodes, or sprinkle conductive liquid such as acid solution in the vicinity of the capacitor.

3). Avoid splashing water or oil in the use environment, avoid direct sunlight, ultraviolet radiation, radiation, toxic gases, vibration or mechanical shock.

D). Maintenance and inspection

Please periodically check the capacitors installed on industrial equipment. The test items are as follows:

Appearance: obvious defects, such as explosion-proof valve opening, electrolyte leakage, etc.

Electrical properties: capacitance, loss tangent, leakage current, etc. For specific data, please refer to Huahui product target and related product specifications.

E). Emergency situation

1). If you see smoke from the explosion-proof valve, turn off the main switch or unplug the clutch.

2). If inhaling gas or ingesting electrolyte, immediately wash the mouth and throat with water.

3). If the skin is stained with electrolyte, wash it off with soap and water.

 F) .Storage

1) .Do not store capacitors where temperature and temperature are high.

Storage environment should be temperature: 5 ° C -35 ° C, relative humidity: <75%, storage location: indoor.

2). Avoid water, salt water or oil in the storage environment of the capacitor.

3). Avoid exposing the capacitor to ozone, ultraviolet light or radiation.

G). Disposal

Please dispose of the capacitor in any of the following ways:

1). Inject holes in the capacitor case or crush the capacitor and incinerate. .

2). If it is not possible to incinerate, please hand it to the waste disposal agency for landfill.