Application technology and precautions of electrolytic capacitor

2023-12-26

Aluminum electrolytic capacitors are of bipolar structure. Attention shall be paid to the polarity during installation and shall not be reversed. The application of AC or reverse voltage may cause short circuit or damage the capacitor: the polarity in AC circuit may be reversed or uncertain, so bipolar capacitors are not suitable for AC applications

The DC voltage loaded to the capacitor terminal shall not exceed its rated working voltage, otherwise the leakage current will increase rapidly, which will damage the capacitor, and even lead to short circuit and open fire. In order to prolong the service life of the product, it is recommended to use the capacitor at 70-80% of the rated voltage

The ripple current loaded to the capacitor must be within the allowable range. If overloaded, the capacitor will overheat and damage its performance, the machine will be damaged, and even open fire will be caused. Please note that the sum of ripple voltage and peak DC working voltage shall not exceed the rated DC voltage

The capacitor must be used within the allowable range of its working temperature, and the service life can be extended under room temperature working conditions

Capacitors with shell diameter greater than or equal to 8mm are equipped with a safety valve. In the solder chip capacitor, the safety valve is usually located at the bottom of the shell, and the screw capacitor is usually located at the outgoing end face (cover plate) of the capacitor. Sufficient space shall be reserved around the valve to maintain the best working condition. The recommended dimensions are as follows: when d = 18 ~ 35mm, more than 3mm space shall be reserved; when d = 40mm or above, more than 5mm space shall be reserved.

When the internal pressure of the capacitor is too high, the gas will be released through the safety valve, resulting in gaseous liquid around the safety valve, which is not a leaking electrolyte.

When installing the capacitor on the circuit board, pay attention not to face down the safety valve, and do not walk any metal or circuit near the safety valve. However, when installing screw aluminum electrolytic capacitor on the side, ensure that the negative electrode is below the positive electrode and do not reverse the voltage. Otherwise, it may lead to excessive pressure, large leakage of electrolyte, short circuit and even open fire.

The capacitor shall be stored in normal temperature and normal humidity environment without acid and alkali. Exposure to high temperatures, such as direct sunlight, will reduce its service life. If stored in acidic or alkaline environment, the solderability of the lead will be affected.

After long-term storage, the leakage current of aluminum electrolytic capacitor may increase. Therefore, it must be formed by applying the rated working voltage for 6-8 hours before use

Manual welding: a must be carried out under the specified conditions, the temperature is 350 ℃, and the use time of soldering iron is 3 seconds. B. ensure that the soldering iron will not touch any part of the capacitor body.

Do not use or place in the environment containing hydrogen sulfide, nitrite, sulfite, chlorine, ammonia and other harmful gases. If the above gas intrudes into the capacitor, it will cause damage to the capacitor

Do not use or place in places exposed to ozone, ultraviolet and radiation

Do not use in places with excessive vibration or impact. If the capacitor falls freely, it will immediately lead to increased leakage and other problems.