The main methods for identifying the positive and negative poles of surface mount electrolytic capacitors are as follows:

1、 Appearance feature judgment

Black marking or strip: Typically, the negative electrode of a surface mount electrolytic capacitor has

 a black strip or mark, while the positive electrode does not. This is the most direct and commonly used

 method of judgment.

Pin length: In some cases, if there is no obvious black mark on the capacitor, it can be determined by 

the length of the pin. The long leg is usually the positive pole, and the short leg is the negative pole. 

However, it should be noted that not all surface mount electrolytic capacitors are suitable for this 

method, as the pin lengths of some capacitors may be the same or the differences may not be significant.

PCB layout: On the PCB board, if there are two semicircles marked at the capacitor positions, the pins

 corresponding to the colored semicircles are usually negative.

2、 Measuring with a multimeter

When it is impossible to accurately determine the positive and negative poles of a surface mount 

electrolytic capacitor based on its appearance characteristics, a multimeter can be used for measurement. 

Here are several commonly used measurement methods:

Voltage testing method:

Set the multimeter to DC voltage mode.

The red probe is grounded (or connected to a known negative electrode), and the black probe is connected 

to one end of the surface mount electrolytic capacitor.

If the voltage displayed on the multimeter is positive, then the terminal connected to the black probe is

 positive; If the displayed voltage is negative, the terminal connected to the black probe is negative.

Capacity testing method:

Set the multimeter to capacitor mode.

Connect the red probe to the ground and the black probe to one end of the surface mount electrolytic

 capacitor.

If the capacity displayed on the multimeter is positive, then the terminal connected to the black probe 

is positive; If the displayed capacity is negative, the terminal connected to the black probe is negative.

Impedance testing method:

Set the multimeter to resistance mode.

Connect the red probe to the ground and the black probe to one end of the surface mount electrolytic

 capacitor.

If the impedance displayed on the multimeter is positive, then the terminal connected to the black 

probe is positive; If the displayed impedance is negative, the terminal connected to the black probe is 

negative.

It should be noted that the above measurement methods can only determine the polarity of surface

 mount electrolytic capacitors, but cannot determine their capacity and quality. In addition, during the

 measurement process, it should be ensured that the multimeter gear is selected correctly and safe

 operating procedures are followed.

3、 Precautions

Polarity importance: Electrolytic capacitors are polarized capacitors and cannot accept reverse voltage.

 Therefore, it is necessary to connect according to the correct polarity during installation and use, 

otherwise it may cause capacitor damage or circuit failure.

Preparation before measurement: Before using a multimeter for measurement, ensure that the 

capacitor has been fully discharged to avoid any impact or safety hazards caused by the stored charges

 inside the capacitor on the measurement results.

Reference technical manual: Surface mount electrolytic capacitors of different models and 

specifications may have different appearance characteristics and measurement methods. Therefore, in

 practical operation, it is necessary to refer to the technical manuals of relevant capacitors or consult 

professionals to obtain accurate information.

About Us

Guangdong Fulong Electronic Technology Co., Ltd. is a private high-tech enterprise specializing in the research and development, manufacturing, and sales of aluminum electrolytic capacitors, certified by IATF16949，ISO9001, ISO14001, and ISO45001. The company has a building area of 17000 square meters and more than 50 automated production lines; The total investment is 50 million yuan (RMB), with more than 100 employees, including more than 20 engineering and technical, quality management, and production management personnel. The annual production of capacitors (4 * 5.4~16 * 21.5) is about 400 million pieces; Our products are mainly sold to domestic and international markets, and we strive to promote our company's products globally.

Jiangxi Fulong Electronic Technology Co., Ltd. is a wholly-owned subsidiary of Guangdong Fulong Electronic Technology Co., Ltd. established in Hukou County, Jiangxi Province with a total investment of 500 million yuan. It has 50 fully automated production lines and an annual output of approximately 1.2 billion capacitors (4 * 5.4~16 * 21.5).

Fulong Group has an international professional core technology research and development team for aluminum electrolytic capacitors and a global sales network. Rich experience in the design, research and development, and production management of aluminum electrolytic capacitors. The R&D team follows the technical design theory of aluminum electrolytic capacitors, complies with international and domestic legal and regulatory requirements (RoHs), and adheres to the highest international quality standards

Fulong Group has high-quality and stable raw material supply partners, and key raw materials (such as aluminum foil, electrolytic paper, etc.) are selected from well-known Japanese and Korean companies (KJCC KDKNKK, etc.), ensuring reliable and stable advantages in product quality, environmental protection, safety, and energy conservation.

Fulong Group has a group of highly qualified professional technicians and management personnel who can produce various series of sheet aluminum electrolysis products according to customer requirements. The products include high-frequency low impedance, low leakage, wide temperature, extremely low impedance, non-polar, ultra long life, medium high voltage long life, high reliability and other new types of special requirements for surface mount products; At the same time, the company's products can withstand a soldering temperature of 260 ℃, meeting the lead-free reflow soldering technology required for SMT in the whole machine factory. All technical indicators of the products have reached or exceeded the international level of similar products.

While strengthening management and expanding operational scale, Fulong Group is also committed to improving its competitiveness and customer satisfaction, continuously and steadily increasing customer and social trust, continuously meeting market demand, further optimizing environmental management and expanding social contributions, and developing together with the electronics industry.

Guangdong Follon Electronic Technology Co., Ltd.

Jiangxi Follon Electronic Technology Co., Ltd.

Address: Building 3, South District, Haishan Science and Technology Park, Hukou County, Jiujiang City, Jiangxi Province

www.follon.com

Professional manufacturer of high-quality surface mount electrolytic capacitors