Special attention should be paid to polarity elements throughout the PCBA process, as directional component errors can lead to batch accidents and failure of the entire PCBA board. Therefore, it is extremely important for engineering and production personnel to understand SMT polarity elements.
I. Definition of polarity
Polarity refers to that the positive and negative poles or first pins of components are in the same direction with those of PCB(printed circuit board). If the direction of components and PCB does not match, it is called bad reverse.
II. Polarity identification method
1. Resistor of the chip type is without polarity
2. Capacitor (Capacitor)
2.1 Ceramic capacitors are non-polar
2.2 Tantalum capacitors are polar. PCB board and device positive pole labeling :1) Ribbon labeling; 2) Mark “+”; 3) Bevel marking.
2.3 Aluminum electrolytic capacitor has polarity. Part labeling: the color band represents negative; PCB marking: The ribbon or “+” represents the positive pole.
3. Inductor
3.1 There is no polarity requirement for two welding end packages such as chip coil.
3.2 Multi-pin inductors have polarity requirements. Part marking: dot/” 1 “stands for polarity point; Mark on PCB: Dot/circle/” * “indicates polarity.
4. Light Emitting Diode
4.1 THE SMT table sticker LED has polarity. Part negative marker: green is negative; PCB negative marker :1) vertical bar, 2) ribbon, 3) silk screen sharp Angle; 4) Screen printing is “distinctive” box representative.
5. Diode (9W)
5.1 The diode with SMT table paste has polarity. Part negative marker :1) ribbon, 2) groove, 3) color marker (vitreous); PCB modernizing room :1) vertical bar, 2) ribbon, 3) screen printing horn, 4) “Modernizing” box.
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Post time: Nov-04-2020