How to recognize Gold Finger on PCB
1. The definition and function of the golden finger:
Gold Finger: (Gold Finger or Edge Connector)
Insert one end of the PCB into the connector card slot, and use the connector pin as the external connection of the pcb board to make the pad or copper contact with the corresponding pin. To achieve the purpose of conduction, and plated nickel or gold on this pad or copper of pcb board, because it is a finger shape, it called gold finger. The reason why gold is chosen is because of its superior conductivity and oxidation resistance. But because the cost of gold is extremely high, it is only use gold plating on small area such as gold fingers.
2. Gold finger classification and identification, characteristics
1).regular gold finger (flush finger) : the square pads with the same length and width is arranged neatly at the edge of the board. Apply to Network,GPU, other boards with less gold finger.
2). Long and short gold fingers (ie, uneven gold fingers): rectangular pads with different lengths at the edge of the board. Apply to: Memory, U disk, Card Reader and other types of objects.
3).Segmented gold finger (intermittent gold finger) : a rectangular pad with different lengths at the edge of the board, and the front section is in-connected.
no silk screen fram or lable,regular with all opening in solder mask layer, most of them has groove on shape, and Gold Finger outside of board edge or close to edge. Some boards with Gold finger at both ends, regular board with Gold Finger in front and bottom side. Part of PCBs with gold finger only on one side; Some pcb board with large width in single finger.