Surface mount capacitors are core electronic components used in automotive electronics, smartphones, smart homes, and other fields. Every circuit board contains a variety of surface mount capacitors. So, how do you identify the material of surface mount capacitors?
Surface Mount Capacitors: Standard Type, Ceramic. Single appearance, no silk-screen printing, non-polar. Available in various colors such as brown, gray, light purple, etc. Basic unit of standard surface mount capacitors: PF.
2. SMD Multilayer Capacitors: Standard type, material: paper. The surface components of the manufacturers have screen printing, with shapes primarily elliptical and square. The elliptical appearance is usually silver and metallic. The square is brown, and the layered paper medium can be seen from the side. This capacitor is non-polar. Available in various sizes, but typically quite large. The basic unit for standard SMD capacitors is pf. However, these capacitors are usually larger in the μF range.
3. SMD Tantalum Capacitors: Material - Tantalum Dielectric. Surface features include screen printing and polarity. Available in many colors, predominantly black, yellow, etc. The SMD tantalum capacitor has a white screen printing to indicate the positive terminal of the capacitor, with the capacitance value and working voltage noted on the screen printing. Most manufacturers also add some tracking marks on the screen printing. Basic unit of SMD tantalum capacitors: μF
4. SMD Electrolytic Capacitors: Material - electrolyte. Surface features include screen printing and polarity. The aluminum housing is visible in appearance. The electrolytic capacitor has a black screen printing to indicate the negative pole, with the capacitance value and working voltage noted on the screen printing. Most manufacturers also add some tracking marks on the screen printing. The basic unit of SMD electrolytic capacitors: μF
One type is a common surface mount electrolytic capacitor, which is in the shape of a cylindrical cube, with the "+" marked end being positive; the other is a silver surface mount capacitor, likely an aluminum electrolytic one. It is round at the top and square at the bottom, and is commonly found on CD-ROM circuit boards. This type of capacitor has the "-" marked end being negative.
The Application of SMD Electrolytic Capacitors: Due to the high capacitance capability of electrolytic capacitors, ranging from hundreds to thousands of microfarads (UF) or even up to tens of thousands, they are the first choice for low and medium-frequency filtering circuits. It is important to note that most electrolytic capacitors have polarity, so the positive and negative terminals must not be reversed, even if polarity is accidentally reversed during measurement with a regular multimeter.
