常见SMT极性元器件识别方法
Common identification methods of SMT polarity components
极性元件在整个PCBA加工过程中需要特别注意，因为方向性的元件错误会导致批量性事故和整块PCBA板的失效，因此工程及生产人员了解SMT极性元件极为重要。
Polar components need special attention in the whole PCBA processing process, because the wrong directional components will lead to batch accidents and the failure of the whole PCBA board, so it is very important for engineering and production personnel to understand SMT polar components.
一、极性定义
1、 Definition of polarity
极性是指元器件的正负纤维 驱鸟设备 保定通风管道 塑料土工格栅 检查井模具 流水槽模具 锻造厂家 华尔街铜牛极或第一引脚与PCB（印刷电路板）上的正负极或第一引脚在同一个方向，如果元器件与PCB上的方向不匹配时，称为反向不良。
Polarity refers to the fact that the positive and negative poles or the first pin of the component are in the same direction as the positive and negative poles or the first pin on the PCB (printed circuit board). If the direction of the component does not match that of the PCB, it is called reverse poor