WEE Technology Company Limited - WEE are Capacitors Specialist
WEET is famous in producing all kinds of aluminum electrolytic capacitors. Today we would like to share 6 failure modes and cause analysis about aluminum electrolytic capacitor. All the information is collected by WEET engineers and for knowledge reference only. If you have other opinions, welcome to email us and discuss with WEET engineers.
1、 Concept of aluminum electrolytic capacitor
Aluminum electrolytic capacitor is made of aluminum cylinder as negative electrode, which is filled with liquid electrolyte and inserted into a bent aluminum strip as positive electrode. It also needs DC voltage treatment to form an oxide film on the positive plate. It is characterized by large capacity, but large leakage, poor stability, positive and negative polarity, suitable for power filter or low-frequency circuit.
2、 Common failure modes of aluminum electrolytic capacitors
When the capacitor fails, the material, structure, manufacturing process, performance and service environment of all kinds of capacitors are different, and the failure mechanism is also different. Today, easy capacity network will reveal common failure modes of aluminum electrolytic capacitors: leakage, explosion, open circuit, breakdown, deterioration of electrical parameters, etc.
3、 Failure mode and cause analysis
A. Leakage
Leakage is one of the causes of capacitor failure, and aluminum electrolytic capacitor is no exception. The working electrolyte of aluminum electrolytic capacitor is acidic. If it overflows, it will seriously pollute and corrode other components and printed circuit board around the capacitor. At the same time, the electrolyte in the electrolytic capacitor dries up gradually due to leakage, which leads to the failure of capacitor due to breakdown or deterioration of electrical parameters. There are many causes of leakage, such as:
① The sealing of aluminum electrolytic capacitor is poor;
② If the aluminum electrolytic capacitor is sealed with rubber plug, the rubber may be aged and cracked due to its long service life;
③ There are some problems in mechanical seal technology;
④ Generally, the manufacturer will consider the problem of liquid leakage. They will specify in the enterprise standard that vertical installation is required, while some enterprises adopt horizontal installation.
B. Explosion
When the working voltage of aluminum electrolytic capacitor is too large, or there are many defects in the oxide film medium, or there are harmful anions such as chlorine radical and sulfate radical, so that when the leakage current is large, the rate of gas generated by electrolysis is faster. The longer the working time is, the greater the leakage current, the more gas in the shell and the higher the temperature. The pressure difference inside and outside the metal shell of capacitor will increase with the increase of working voltage and working time. If the sealing is good and there is no explosion-proof measures, the capacitor will explode when the air pressure increases to a certain extent.
WEE Technology Company Limited - WEE are Capacitors Specialist
The positive and negative polarity will be marked on the shell of electrolytic capacitor, and attention must be paid to its polarity in actual use, otherwise there is a risk of explosion. If the polarity of an electrolytic capacitor can not be recognized, its polarity can be judged with a pointer multimeter.
So how to identify the polarity of Electrolytic capacitor by Multimeter?
Due to the difference between positive and negative polarity of electrolytic capacitor, it has a feature of using multimeter resistance to detect it: the positive electrode is connected with black probe (positive power supply), the negative terminal is connected with red probe (negative power supply), and the leakage current of electrolytic capacitor is small (Large leakage resistance). On the contrary, the leakage current of electrolytic capacitor increases (the leakage resistance decreases).
When measuring, first assume that one pole is "+" pole, connect it with the black probe of the multimeter, and connect the other electrode with the red probe of the multimeter. Record the scale of the stop of the probe (the resistance value of the probe is large on the left side), then discharge the capacitor (i.e. the two leads touch each other), exchange the two probes, and re measure. In the two measurements, the last time the needle stays on the left (with high resistance), the black probe is connected to the positive electrode of the electrolytic capacitor.
At the same time, you can tell the polarity of WEET Axial Electrolytic capacitors by external appearance. Firstly, on one side of the lead, there is a protruding end, which is a negative pole. At the same time, the sleeve marking will has a "-" one it and arrow to one side , which is showing as negative pole.
WEE Technology Company Limited - WEE are Capacitors Specialist
The main applications of the polarized axial Aluminum Electrolytic Capacitors products are: frequency converter, frequency conversion air conditioner, welding machine, inverter power supply, switching power supply, high-quality electronic machine, high-grade audio frequency division, computer motherboard, intelligent instrument, power wave of industrial control equipment, medical equipment, household appliances, communication power supply, etc...
Widely used in smart meters, electric vehicle charger controller, car navigation box, vehicle electronic equipment, POS card reader, smart meter, TV set-top box, satellite receiver, VCD / DVD, audio amplifier, car audio, charger, telephone, instrument, electronic ballast, electronic energy-saving lamps, lighting, financial equipment and appliances, medical electronic equipment and other electronic equipment Products.
WEE Technology Company Limited - WEE are Capacitors Specialist
WEET WMS - Non-Polarized 1000H at 105°C, DF at Max 10% BP Axial Aluminum Electrolytic Capacitors for Audio Applications
Below is WMS hot and common capacitance, free samples on request, welcome to contact with WEET capacitor.
| 1μF 100VDC +/-10% D*L: 8*17mm |
| 1.5μF 100VDC +/-10% D*L: 8*18mm |
| 2.2μF 100VDC +/-10% D*L: 8*18mm |
| 2.7μF 100VDC +/-10% D*L: 8*18mm |
| 3.3μF 100VDC +/-10% D*L: 8*18mm |
| 3.9μF 100VDC +/-10% D*L: 8*18mm |
| 4.7μF 100VDC +/-10% D*L: 10*19mm |
| 5.6μF 100VDC +/-10% D*L: 10*20mm |
| 6.8μF 100VDC +/-10% D*L: 10*20mm |
| 8.2μF 100VDC +/-10% D*L: 10*20mm |
| 10μF 100VDC +/-10% D*L: 10*20mm |
| 12μF 100VDC +/-10% D*L: 10*20mm |
| 15μF 100VDC +/-10% D*L: 10*20mm |
| 18μF 100VDC +/-10% D*L: 10*20mm |
| 22μF 100VDC +/-10% D*L: 10*24mm |
| 27μF 100VDC +/-10% D*L: 13*27mm |
| 33μF 100VDC +/-10% D*L: 13*27mm |
| 39μF 100VDC +/-10% D*L: 13*27mm |
| 47μF 100VDC +/-10% D*L: 13*27mm |
| 56μF 100VDC +/-10% D*L: 13*32mm |
| 68μF 100VDC +/-10% D*L: 13*32mm |
| 82μF 100VDC +/-10% D*L: 16*34mm |
| 100μF 100VDC +/-10% D*L: 16*34mm |
| 120μF 100VDC +/-10% D*L: 16*34mm |
| 150μF 100VDC +/-10% D*L: 16*34mm |
| 220μF 100VDC +/-10% D*L: 18*44mm |
| 270μF 100VDC +/-10% D*L: 18*44mm |
| 300μF 100VDC +/-10% D*L: 18*44mm |
| 330μF 100VDC +/-10% D*L: 22*44mm |
WEE Technology Company Limited - WEE are Capacitors Specialist
Do you know, why Axial Aluminum Electrolytic Capacitors must know the polarity? The capacitance of the capacitor is inversely proportional to the square of the distance between the two electrodes and is proportional to the area. The polarity of electrolytic capacitor is determined by the characteristics of its medium (insulator). The medium of electrolytic capacitor is metal oxide film, that is, the electrolytic (DC) process forms an oxide film on the surface of aluminum foil. Because the oxide film is very thin, the capacity of electrolytic capacitor can be very large. If the polarity of the capacitor is reversed, the electrolytic film will be destroyed under the reverse voltage, and the capacitor will fail. Therefore, the electrolytic capacitor has polarity.
WEET WAA 85°C, Low Leakage, 2000 Hours , Polarized Axial Aluminum Electrolytic Capacitor Common Items are as below. WEET is the earliest Polarized Axial Aluminum Electrolytic Capacitor factory in China.
| WAA - 85°C, Low Leakage, 2000 hours , Axial Aluminum Electrolytic Capacitor | Dimension: OD*L (mm) |
| WAA 10uF 160V +/-20% Bulk RoHS* | 10*17 |
| WAA 100uF 100V +/-20% Bulk RoHS* | 13*22 |
| WAA 100uF 35V +/-20% Bulk RoHS* | 8*16 |
| WAA 100uF 63V +/-20% Bulk RoHS* | 10*17 |
| WAA 220uF 100V +/-20% Bulk RoHS* | 16*28 |
| WAA 220uF 35V +/-20% Bulk RoHS* | 10*17 |
| WAA 330uF 25V +/-20% Bulk RoHS* | 10*17 |
| WAA 330uF 35V +/-20% Bulk RoHS* | 10*21 |
| WAA 330uF 63V +/-20% Bulk RoHS* | 13*22 |
| WAA 4.7uF 160V +/-20% Bulk RoHS* | 8*16 |
| WAA 47uF 100V +/-20% Bulk RoHS* | 10*21 |
| WAA 470uF 100V +/-20% Bulk RoHS* | 16*36 |
| WAA 470uF 25V +/-20% Bulk RoHS* | 10*21 |
| WAA 470uF 25V +/-20% Bulk RoHS* | 10*21 |
| WAA 470uF 63V +/-20% Bulk RoHS* | 13*27 |
| WAA 470uF 63V +/-20% Bulk RoHS* | 13*27 |
| WAA 22uF 100V +/-20% Bulk RoHS* | 8*16 |
| WAA 220uF 25V +/-20% Bulk RoHS* | 8*16 |
| WAA 220uF 63V +/-20% Bulk RoHS* | 13*22 |
| WAA 33uF 63V +/-20% Bulk RoHS* | 8*13 |
| WAA 330uF 100V +/-20% Bulk RoHS* | 16*33 |
| WAA 47uF 63V +/-20% Bulk RoHS* | 8*16 |
| WAA 1uF 100V +/-20% Bulk RoHS* | 5*12 |
| WAA 1uF 63V +/-20% Bulk RoHS* | 5*12 |
| WAA 1uF 100V +/-20% Bulk RoHS* | 5*12 |
| WAA 1uF 350V +/-20% Bulk RoHS* | 8*16 |
| WAA 1uF 63V +/-20% Bulk RoHS* | 5*12 |
| WAA 10uF 25V +/-20% Bulk RoHS* | 5*12 |
| WAA 10uF 63V +/-20% Bulk RoHS* | 5*12 |
| WAA 10uF 35V +/-20% Bulk RoHS* | 5*12 |
| WAA 10uF 350V +/-20% Bulk RoHS* | 13*22 |
| WAA 10uF 63V +/-20% Bulk RoHS* | 6.3*13 |
| WAA 100uF 16V +/-20% Bulk RoHS* | 6.3*13 |
| WAA 100uF 25V +/-20% Bulk RoHS* | 8*13 |
| WAA 100uF 350V +/-20% Bulk RoHS* | 22*40 |
| TS13AH 2.2uF 50V +/-20% Bulk RoHS* | 5*12 |
| TS13AH 3.3uF 50V +/-20% Bulk RoHS* | 5*12 |
| WAA 2.2uF 100V +/-20% Bulk RoHS* | 5*12 |
| WAA 2.2uF 350V +/-20% Bulk RoHS* | 10*17 |
| WAA 2.2uF 63V +/-20% Bulk RoHS* | 5*12 |
| WAA 2.2uF 63V +/-20% Bulk RoHS* | 5*12 |
| WAA 22uF 16V +/-20% Bulk RoHS* | 5*12 |
| WAA 22uF 25V +/-20% Bulk RoHS* | 6.3*13 |
| WAA 22uF 35V +/-20% Bulk RoHS* | 6.3*13 |
| WAA 22uF 350V +/-20% Bulk RoHS* | 13*27 |
| WAA 3.3uF 63V +/-20% Bulk RoHS* | 5*12 |
| WAA 33uF 350V +/-20% Bulk RoHS* | 16*33 |
| WAA 4.7uF 350V +/-20% Bulk RoHS* | 10*21 |
| WAA 4.7uF 63V +/-20% Bulk RoHS* | 5*12 |
| WAA 4.7uF 100V +/-20% Bulk RoHS* | 6.3*13 |
| WAA 4.7uF 63V +/-20% Bulk RoHS* | 5*12 |
| WAA 47uF 16V +/-20% Bulk RoHS* | 6.3*13 |
| WAA 47uF 25V +/-20% Bulk RoHS* | 6.3*13 |
| WAA 47uF 35V +/-20% Bulk RoHS* | 6.3*13 |
| WAA 47uF 350V +/-20% Bulk RoHS* | 16*40 |
WEET How to Understand the of Polarity of Horizontal Axial Through Core Polar Electrolytic Capacitor
WEE Technology Company Limited - WEE are Capacitors Specialist
Aluminum electrolytic capacitor is a kind of capacitor with thin oxide film as the medium, which is made of water absorbing paper with paste electrolyte sandwiched between two aluminum foils. Because the oxide film has unidirectional conductivity, the electrolytic capacitor has polarity.
Today, WEET engineers will show you How to Understand and Test the of Polarity of Horizontal Axial Through Core Polar Electrolytic Capacitors
If the polarity of electrolytic capacitor is unknown, the polarity can be measured by the resistance block of multimeter.
We know that the leakage current of the electrolytic capacitor is small (the leakage resistance is large) only when the positive pole of the electrolytic capacitor is connected to the power supply (the black probe in the resistance block) and the negative terminal is connected to the power supply (the red probe in the resistance block). On the contrary, the leakage current of electrolytic capacitor increases (the leakage resistance decreases).
When measuring, first assume that a certain pole is "+" pole, let it connect with the black probe of the multimeter, and the other electrode connects with the red probe of the multimeter, record the scale of the stop of the probe (the resistance value of the probe to the left is large), then discharge the capacitor (i.e. two leads touch each other), and then adjust the two probes, and measure again. In the two measurements, when the last position of the probe is to the left (high resistance), the black probe is connected to the positive pole of the electrolytic capacitor.
At the same time, we also can distinguish the polarity of WEET Axial WAA Aluminum electrolytic capacitor by external appearance. Firstly, the marking arrow indicated the negative polar. Secondly, the terminal end has an obvious soldering joint and pup up, which means the negative polar.
WAA 470uF 50V 85°C 2000H ±20% is the best seller in WEET capacitors line, welcome your enquiry and request for free samples.
WEE Technology Company Limited - WEE are Capacitors Specialist
WAA - Polarized 2000H at 85°C, Axial Aluminum Electrolytic Capacitors (Low Leakage)
WAB - Polarized 1000H at 105°C, Axial Aluminum Electrolytic Capacitors, Standard Low Voltage
WMM - Bi-Polarized 1000H at 105°C, DF at Max 5% BP Axial Aluminum Electrolytic Capacitors for Audio Applications
WMS - Non-Polarized 1000H at 105°C, DF at Max 10% BP Axial Aluminum Electrolytic Capacitors for Audio Applications
WEE Technology Company Limited - WEE are Capacitors Specialist
| WEET 85°C 2000 Hours V-Chip Aluminum Electrolytic Capacitor (SMD Chip E CAP) | |
| WEET | Standard, 85°C V-chip aluminum electrolytic capacitors |
| Temperature: | -40°C ~ +85°C |
| Load life: | 2000 hrs. |
| Voltage: | 4V ~ 100V.DC |
| Capacitance: | 0.1uF ~ 10000uF |
| Tolerance | ±20% at 120Hz, 20°C |
| Size: | 4x5.4, 5x5.4, 6.3x5.4, 6.3x7.7, 8x6.2, 8x10.5, 10x10.5, 10x13.5,12.5x13.5 |
| WEET 105°C 2000 Hours V-Chip Aluminum Electrolytic Capacitor (SMD Chip E CAP) | |
| WEET | Standard, 105°C V-chip aluminum electrolytic capacitors |
| Temperature: | -40°C~ +105°C |
| Load life: | 2000 hrs |
| Voltage: | 4V ~ 100V.DC |
| Capacitance: | 0.1uF ~ 10000uF |
| Tolerance: | ±20% at 120Hz, 20°C |
| Size: | 4x5.4, 5x5.4, 6.3x5.4, 6.3x7.7, 8x6.2, 8x10.5, 10x10.5, 10x13.5,12.5x13.5 |
| Item | Common Size MM | Special Size MM |
| 1 | 4*5.4 | 6.3*10.5 |
| 2 | 4*5.8 | 8*6.5 |
| 3 | 5*5.4 | 8*10.5 |
| 4 | 5*5.8 | 8*12.5 |
| 5 | 6.3*5.4 | 10*10.5 |
| 6 | 6.3*5.8 | 10*12.5 |
| 7 | 6.3*7.7 | 10*13.5 |
| 8 | 8*6.5 | 10*16.5 |
| 9 | 8*10.5 | 12.5*13.5 |
| 10 | 10*7.7 | 12.5*16 |
| 11 | 10*10.5 | 16*16.5 |
| 12 | 10*13.5 | 16*21.5 |
WEE Technology Company Limited - WEE are Capacitors Specialist
WEE Technology SMD E Cap including 2000 hours at 85°C SMD E Cap and 1000 hours at 105°C SMD E Cap.
Chip type, operating with wide temperature range -40~+105°C.
Designed for surface mounting on high density circuit board.
Tape and reel package is available for automatic insertion.
WEET Aluminum Electrolytic Capacitors - SMD E Cap Common Dimension and Strong Items
| ltem | Dimension(mm) | MOQ/pcs |
| 1 | 4*5.4 | 20,000 |
| 2 | 5*5.4 | 20,000 |
| 3 | 6.3*5.4 | 20,000 |
| 4 | 6.3*7.7 | 20,000 |
| 5 | 8*10.5 | 8,000 |
| 6 | 10*10.5 | 8,000 |
| 7 | 12.5*13.5 | 2,400 |
| 8 | 16*16.5 | 1,000 |
WEE Technology Company Limited - WEE are Capacitors Specialist
The core of aluminum electrolytic capacitor is made of four layers of anode aluminum foil, electrolytic paper, cathode aluminum foil, electrolytic paper, etc. after the core contains electrolyte, it is sealed with aluminum shell and rubber cover to form an electrolytic capacitor. Compared with other types of capacitors, aluminum electrolytic capacitors have the following obvious characteristics in structure:
(1) The working medium of aluminum electrolytic capacitor is to form a very thin layer of aluminum oxide (Al2O3) on the surface of aluminum foil by anodizing. The oxide medium layer and the anode of the capacitor are combined into a complete system, and they are interdependent and cannot be independent of each other. As we usually say, the electrode and dielectric of the capacitor are independent of each other.
(2) The anode of aluminum electrolytic capacitor is the aluminum foil with Al2O3 dielectric layer on its surface. The cathode is not the negative foil we used to think, but the electrolyte of capacitor.
(3) Negative foil plays the role of electrical lead-out in electrolytic capacitor, because the electrolyte as cathode of electrolytic capacitor can not be directly connected with the external circuit, it must form an electrical path through another metal electrode and other parts of the circuit.
(4) The anode aluminum foil and cathode aluminum foil of aluminum electrolytic capacitor are usually corrosion aluminum foil. The actual surface area is much larger than its apparent surface area, which is also a reason why aluminum electrolytic capacitor usually has large capacitance. Due to the use of aluminum foil with many micro etched holes, liquid electrolyte is usually needed to make more effective use of its actual electrode area.
(5) As the dielectric oxide film of aluminum electrolytic capacitor is obtained by anodizing, and its thickness is directly proportional to the voltage applied by anodizing, therefore, in principle, the thickness of dielectric layer of aluminum electrolytic capacitor can be accurately controlled as a technical reference.