SMD Aluminum Electrolytic Capacitors

Introduction: With the development of the times, the demand for electrolytic capacitors for miniaturization and slicing of electrolytic capacitors, the increase in workers’ wages, and the loss of population have been the pressure of electronic technology. In recent years, companies have been solving these problems in the process of economic restructuring and replacing them with machines. The application of artificial and patch electrolytic capacitors also shows an increasing trend. In the future, surface-mounted aluminum electrolytic capacitors will eventually replace traditional plug-in electrolytic capacitors in terms of both quantity and amount. At present, although the electrolytic capacitor of the chip type is higher in price than the conventional plug-in electrolytic capacitor, due to the increase in market demand, the production tends to be large-scale, and the price is declining year by year. During the 2012~20014 three-year period, the average unit price fell by 20 to 30%.

SMD aluminum electrolytic capacitors are even more capable of large-scale production, saving labor, and are subject to corporate bargaining. Following by Dongguan Hua Hui Electronic Technology Co., Ltd. to guide everyone to understand it!

First, the application of SMD aluminum electrolytic capacitors:

SMD electrolytic capacitors act as filters, couplings, DC blocking, and energy storage in circuits and are widely used in various household appliances, computers, mobile communications, automotive electronics, smart grids, aerospace, rail transportation, and other fields. One of the indispensable main components in electronic devices.

Second, SMD aluminum electrolytic capacitor reflow note:

1, should use infrared and hot air reflow soldering, should not use vapor phase heating reflow soldering;

2. It is recommended that reflow soldering be performed only once. If the reflow times are twice, it must be separated by more than 30 minutes.

3, lead-free reflow, please meet the following conditions:

(1) The preheating time from 150°C to 200°C is within 180 seconds;

(2) The welding time of the capacitor top temperature exceeding 217 °C does not exceed tL seconds;

(3) The peak temperature at the top of the capacitor does not exceed Tp°C, and the actual peak temperature time at 5°C does not exceed tp seconds.

Third, SMD aluminum electrolytic capacitor general use matters needing attention:

1, circuit design

(1) Fully consider the use of capacitors and installation conditions within the scope of the Huahui product target

(2) Operating temperature and applied ripple current should be within the specified range of Huahui product target

(3) When designing a circuit, products that meet the requirements of life should be selected

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

(5) For circuits that require fast and frequent charging and discharging, aluminum electrolytic capacitors should not be used. Specially designed capacitors with long life should be selected.

(6) Overvoltage should not be used

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

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

(7) Capacitors cannot be used under the following environmental conditions:

1(a) Capacitors are exposed to water (including concentrates), brine or oil. (b) There are toxic gases such as hydrogen sulfide, sulfurous acid, nitrous acid, chlorine, bromine gas, methane bromine, and ammonia in the surrounding environment. (c) Ozone, ultraviolet light and radiation in the surrounding environment.

2 Severe vibration and mechanical shock exceed the scope of Huahui's product target.

Vibration test conditions are as follows

Vibration frequency range: 10-55-10Hz

Scanning frequency: 10-55-10Hz/minute

Scan method: logarithm

Amplitude or acceleration: 1.5mm (maximum acceleration is 10G)

Vibration direction: X, Y, Z direction

Test time: 2 hours per direction

Shock generally does not apply.

(8) Electrolyte The main chemical solvents and electrolytic paper are flammable materials, and the electrolyte is conductive. When the electrolyte comes into contact with the PC board, the circuit on the PC board may be corroded or a short circuit may occur, resulting in smoke or fire. Therefore, there should not be any lines at the lower end of the capacitor seal.

(9) When designing the circuit board, ensure that the heat-generating component is not close to the other side of the aluminum electrolytic capacitor or the PC board, so as to avoid it being under the capacitor.

(10) When designing a circuit board, it should be considered that the electrical properties of the capacitor may change with changes in temperature and frequency.

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

(12) When installing a capacitor on a double-sided circuit board, the capacitor should be installed so that it avoids excess substrate holes and via holes.

2, installation

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

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

(3) Before installing the container on the PC board, check its specifications and polarity.

(4) Do not drop the capacitor on the ground, or use the capacitor dropped on the ground.

(5) Do not damage the capacitor during installation.

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

(7) Reflow

1 Please follow the reflow conditions in Huahui's product target.

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

(8) Do not tilt or twist the capacitor after soldering the capacitor to the PC board.

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

(10) Do not allow anything to touch 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) Capacitors after soldering shall not be affected by thermal radiation of any soldered PC board or other components.

(12) Cleaning:

1 Can not use halogenated cleaning agent to clean capacitors. If you must use halogenated cleaners, please contact our sales department.

2 push deposit cleaning method:

Range of use: any type and specification

Cleaning method: Soaking, ultrasonic or other methods of cleaning time should be within 2 minutes. Cleaning agent temperature should be below 40 °C. After cleaning, capacitor and PC board should be blown together with hot air for at least 10 minutes. The hot air temperature should be lower than the operating temperature of the capacitor. If not fully dried after washing, it may lead to poor appearance, such as seat plate swell.

3 Avoid using ozone decontamination agents to protect the environment.

3, after installation

(1) Do not touch the positive and negative electrodes of the capacitor by hand.

(2) Do not connect the conductor between the positive and negative electrodes, and do not splash conductive liquids such as bismuth acid solution in or near the capacitor. damage

(3) Splashing with water or oil should be avoided in the use environment. Avoid direct sunlight, ultraviolet radiation, radiation, toxic gases, vibration or mechanical shock.

4, maintenance and inspection

Please regularly check the capacitors installed in industrial equipment. Test items are as follows:

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

Electrical properties: capacitance, loss tangent, leakage current, etc.

5、Emergency

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

(2) If you inhale gas or ingest electrolyte, wash your mouth and throat immediately with water.

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

6, storage

(1) Do not store capacitors in places with high temperatures and temperatures.

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

(3) Avoid water, salt water, or oil in the capacitor's storage environment.

(4) Avoid exposure of capacitors to ozone, ultraviolet light or radiation.

7. Disposal

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

1) Open the hole in the capacitor case or crush the capacitor and incinerate it. .

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

Source: Dongguan Huahui Electronic Technology Co., Ltd.