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Precautions for the use of aluminum electrolytic capacitors

  • 2018-12-20
  • 20

Precautions for the use of aluminum electrolytic capacitors


1 Considerations in circuit design

(1) Designed in the range of the rated performance of the capacitor specified in the product catalog or the specification approval application (hereinafter referred to as the delivery approval) of the capacitor, based on the confirmation of the use environment and the installation environment.

(2) The temperature of use and the ripple current used shall not exceed the limits specified in the catalog or delivery acknowledgement.

1 Do not use at temperatures above the upper limit temperature (maximum operating temperature).

2 No current can be connected (current exceeding the rated ripple current).

(3) When designing the circuit, use a capacitor that matches the life of the machine.

(4) The capacitor is a polar capacitor. Be sure to connect the reverse voltage or AC voltage. Use a bipolar polarity capacitor in the polarity reversal circuit. However, bipolar capacitors cannot be used in AC circuits.

(5) Select a capacitor that matches the conditions of use in the circuit that repeats the rapid charge and discharge. As a circuit that repeats rapid charging and discharging, such as an electric welder, a camera flash, and the like. In addition, the control circuit of a rotating machine such as a servo motor with a large fluctuation in circuit voltage repeats rapid charge and discharge. For repeating the capacitor used in the rapid charge and discharge circuit, please contact us.

(6) Please confirm that there is no excess voltage (voltage exceeding the rated voltage) through the capacitor.

1 Note that the peak value when the ripple voltage (AC part) overlaps with the DC voltage cannot exceed the rated voltage.

2 When two or more capacitors are connected in series, the voltage passing through each capacitor should be controlled below the rated voltage. Further, at this time, a voltage dividing resistor in consideration of the leakage current is added in parallel with each capacitor.

(7) The capacitor should be completely isolated from the circuit between the following.

(The aluminum oxide and cathode terminals of the capacitor are connected by the natural oxide film on the inside of the case and the unstable resistance part of the electrolyte)

1 between the aluminum shell and the cathode terminal (except for the reverse of the lead terminal) and between the anode terminal and the circuit board.

2 substrate between the self-standing blank terminal and other anode terminals and between the cathode terminal and the circuit board.

3 between the two terminals of the bipolar capacitor and the aluminum case.

(8) The package sleeve of the capacitor is not insulated to ensure shape. Do not use in places where insulation is required. Please consult us if you need a jacket with insulation.

(9) Capacitors may sometimes malfunction if they are used in the following environments.

1 ambient (weather resistance) conditions

(a) direct splashing environment, high temperature and high humidity environment and dew condensation environment (b) direct splashing environment and oil mist filled environment

(c) Direct splashing of salt water and a salt-filled environment

(d) Environments filled with toxic gases (hydrogen sulfide, sulfurous acid, chlorine, bromine, methyl bromide, ammonia, etc.) (e) environments with direct sunlight, ozone, ultraviolet light and radiation

(f) an environment in which acidic and alkaline solvents are splashed

2 Harsh or shock conditions exceed the harsh environment specified in the delivery acknowledgment

(10) When mounting the capacitor on a printed circuit board, please confirm the following beforehand and design.

1 Align the hole spacing of the printed circuit board with the terminal spacing of the capacitor.

2 The wiring and circuit board should not be placed close to the pressure valve part of the capacitor during design.

3 As long as there is no provision in the delivery confirmation, the interval of the pressure valve part of the capacitor shall be as follows. Product diameter interval

Φ8 ~ Φ16mm 2mm or more

Φ18 ~ Φ35mm 3mm or more


1 When the pressure valve of the capacitor is installed on one side of the printed circuit board, please align the position of the pressure valve and open the vent hole when the pressure valve is working.

2 Place the screw terminal-shaped sealing part up. Also, when placing it horizontally, place the anode terminal up.

(11) If there is a template on the lower surface of the capacitor sealing part, if the electrolyte leaks, the circuit may be short-circuited, causing leakage or migration. Therefore, do not route the circuit board under the capacitor sealing part.

(12) Do not place heat-generating parts around the capacitor and on the back side of the printed circuit board (below the capacitor).

(13) The pad pattern of the printed circuit board for chip capacitors should be designed with reference to the recommended pattern of the product catalog or delivery approval.

(14) The electrical characteristics of the capacitor vary depending on changes in temperature and frequency. Please design the circuit based on the confirmation of the change.

(15) When mounting a capacitor on a double-sided printed circuit board, when designing the circuit, design the circuit so that there are no excess printed circuit board holes and through-holes for connecting the front and back sides of the capacitor.

(16) The tightening torque of the screw terminal and the tightening torque of the capacitor for the subject installation shall not exceed the range specified in the delivery confirmation.

(17) When two or more capacitors are connected in parallel, it is necessary to fully consider the current balance.

(18) When connecting two or more capacitors in series, consider the voltage balance and insert the voltage divider resistor in parallel with the capacitor.



2 Installation precautions

(1) Do not use the capacitor that has been energized on the device. Except for capacitors that are removed for periodic inspection during electrical inspection, they cannot be used again.

(2) Even if the capacitor is discharged, a voltage (re-flash voltage) may be generated between the terminals. In this case, discharge through a 1kΩ resistor.

(3) The leakage current of capacitors stored for more than half a year may increase. In this case, perform voltage processing with a 1kΩ resistor.

(4) After confirming the rated value (electrostatic capacity and voltage) of the capacitor, install it.

(5) After confirming the polarity of the capacitor, install it.

(6) Do not drop the capacitor to the ground. Do not use a capacitor that has fallen behind.

(7) Do not deform the capacitor body during installation.

(8) Check that the terminal spacing of the capacitor matches the hole spacing of the printed circuit board before mounting.

(9) The substrate self-standing capacitor is pushed into a degree of adhesion to the substrate (non-floating state) at the time of mounting.

(10) The strength of the fixed capacitor lead by kinking with an automatic insertion machine should not be too large.

(11) Please pay attention to the impact force caused by the auto-insertion machine and the applicator's adsorber, product tester and alignment operation.

(12) Welding using a soldering iron

1 Welding conditions (temperature, time) must not exceed the range specified in the delivery confirmation.

2 When the lead terminals need to be machined due to the inconsistency between the terminal spacing and the printed circuit board hole spacing, the capacitor body must not be subjected to pressure during processing before soldering.

3 When using a soldering iron for trimming, if you need to remove the soldered capacitor first, melt the solder and then disassemble it to prevent the capacitor terminals from receiving pressure.

4 Do not allow the soldering iron tip to touch the body of the capacitor.

(13) Flow welding

1 When soldering, do not immerse the capacitor body in solder. Insert the printed circuit board and solder only the opposite side of the capacitor side.

2 Welding conditions (preheating, welding temperature, terminal immersion time) must not exceed the range specified in the delivery confirmation.

3 No flux is attached except for the terminal.

4 When soldering, care should be taken to prevent other components from tipping over the capacitor.

(14) Reflow soldering

1 Welding conditions (preheating, soldering temperature, time) must not exceed the range specified in the delivery confirmation.

2 When an infrared heater is used, since the infrared absorption rate differs depending on the color and material of the capacitor, it is necessary to pay attention to the degree of heating.

3 Set the number of reflows of the capacitor to 1 time. However, if it is necessary to set the return to 2 times, please consult us.





(15) Among the halogen-free fluxes, some do not contain ionic halogen compounds, but contain a large amount of nonionic halides. When such compounds enter the capacitor, they will chemically react with the electrolyte, possibly resulting in The same adverse effects after washing. Use a flux that does not contain a non-ionic halogen compound.

(16) When the capacitor is placed in an environment of 150 ° C for 2 minutes or more due to preheating of the surface mount component and hardening of the resin for fixing the capacitor, or when the high temperature gas or the hot wire is in direct contact with the capacitor, the outer case may be caused. Contraction, expansion, and rupture occur.

(17) After soldering the capacitor to the printed circuit board, the capacitor body must not be tilted, laid down, or twisted.

(18) After the capacitor is soldered to the printed circuit board, the capacitor cannot be used as a handle to move the printed circuit board.

(19) After soldering the capacitor to the printed circuit board, do not allow other objects to collide with the capacitor. In addition, when the printed circuit board is placed in an overlapping position, the printed circuit board or other components cannot be touched by the capacitor.

(20) Cleaning Cleaning method Object: All varieties, all specifications Ethanol cleaning agent

Isopropyl alcohol aqueous cleaning agent

Advanced ethanol


PineAlpha ST-100S Techno Care FRW14 ~ 17

Sanelek B-12


CleanThrough 750H, 750L.710M

Alkaline saponifier


Aqua Cleaner 210SEP

Cleaning conditions: using a method such as dip-bonding, ultrasonic, etc., the cleaning time is no more than 5 minutes. (When the cleaning solution temperature is 60 ° C or lower) After cleaning, please dry the capacitor and the mounted printed circuit board with hot air for 10 minutes or more. The temperature of the hot air should be controlled below the upper limit of the classification temperature. In addition, if the drying is insufficient after washing, it may cause poor appearance such as secondary shrinkage of the outer cover and expansion of the bottom plate. Need to pay attention. Please fully manage the pollution of the cleaning agent (conductivity, pH, specific gravity, water content, etc.). After cleaning, do not store it in the environment of the cleaning solution or in a sealed container. Depending on the cleaning method, sometimes the product label disappears or the label is blurred.

(21) Fixing agent, filming agent

1 Do not use a fixing agent or a coating agent containing a halogen-based solvent.

2 Before using the fixative or the coating agent, clean the sealing between the substrate and the capacitor, and do not leave any flux residue or dirt.

3 Before using a fixative or a coating agent, dry the cleaning agent.

4 When using a fixative or a film, do not block the entire surface of the capacitor sealing part. There are many types of fixatives and coating agents. Please consult us for details.

(22) Regarding the fumigation treatment, it is sometimes necessary to carry out fumigation treatment with a halogen compound as an insect control measure at the time of export. When the aluminum electrolytic capacitor and the machine equipped with the aluminum electrolytic capacitor are directly fumigated or the fumigation treated wood is used for the bracket, the fumigant contains halogen, which may cause corrosion reaction inside the capacitor.

3 Equipment Usage Precautions

(1) Direct contact with the terminals of the capacitor may result in electric shock.

(2) It is not possible to short-circuit the capacitor terminals between the conductors. Further, the capacitor should not be exposed to a conductive solution such as an aqueous solution of an acid or a base.

(3) Make sure that the installation environment of the device equipped with the capacitor does not belong to the following environment.

1 places where water splashes directly, places with high temperature and high humidity, and places where condensation is easy.


2 Locations where oil splashes directly and places filled with oil mist.


3 places where water is directly splashed, places with high temperature and high humidity, and places where condensation is easy.

4 A place filled with acidic organic gases (hydrogen sulfide and sulfurous acid, nitrous acid, chlorine, bromine, methyl bromide).

5 A place filled with alkaline or other toxic gases (ammonia, etc.).

6 Locations where acidic and alkaline solvents are splashed.

7 Condensation environment may cause the jacket to shrink, swell, and rupture, so please fully confirm it when using it. In addition, when condensation occurs due to drastic changes in temperature, high temperature and high humidity tests, etc., the same jacket abnormality may also occur.

4 maintenance and repair

(1) Periodic inspection of capacitors used in industrial machines. The maintenance items include the following.

1 Appearance: There are obvious abnormalities such as valve opening and liquid leakage.

2 Electrical performance: the leakage current, electrostatic capacity, tangent of the loss angle and the items specified in the catalog or delivery acknowledgement.

5 Emergency

(1) When the pressure valve of the capacitor is opened and the gas (white smoke) is emitted during the use of the device, the main power of the device should be cut off or the power cord plug should be unplugged from the device.

(2) When the pressure valve of the capacitor is working, high temperature gas exceeding +100 °C will be sprayed, and the face should not be approached at this time. Immediately wash the eye or mouth with water as soon as the ejected gas enters the eye or is inhaled. Do not eat the electrolyte of the capacitor. If the electrolyte splashes on the skin, rinse it with soapy water.

6 Storage conditions

(1) For the storage of capacitors, it is recommended to store at room temperature of 5~35 °C and relative humidity of 75%.

(2) Please confirm that the storage location does not belong to the environment described in the precautions (3) of the three items.

(To maintain good solderability of aluminum electrolytic capacitors, please observe the following items.)

1) Store in a sealed state with a plastic bag before use.

2) Please unpack the plastic bag before use and use the product once. If you cannot use it all at once, put the remaining product back in the bag and seal it with tape or the like.

3) Maintain good solderability, please keep the product storage period within half a year.

7 Disposal

(1) When discarding a capacitor, any of the following methods can be used.

1 Insulate the capacitor by opening it or fully breaking it.

2 When not burning capacitors, they should be handed over to a professional industrial waste treatment plant for landfill disposal.

(2) When discarding the capacitor (from the substrate connected to it), check if it has been discharged.

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