Gold Fingers are the gold-plated conductors that located along the connecting edges of printed circuit boards (PCBs). The purpose of gold fingers is to connect a secondary PCB to the motherboard. PCB gold fingers are also used in various other devices that communicate via digital signals, such as smartphones and smartwatches. Gold is used for the connecting points along a PCB because of the alloy’s superior conductivity. An example would be a PCI card inserted into a PCI slot in PC.
The hard gold plating allows for the PCB to be inserted into a connector without damaging the surface of the connections. Two types of gold applicable to the PCB gold finger plating process:
- Electroless Nickel Immersion Gold (ENIG): This gold is more cost-effective and easier to solder than electroplated gold, but its soft, thin (typically 2-5μ” composition renders ENIG unsuitable for the abrasive effects of circuit board insertion and removal.)
- Electroplated Hard Gold: This gold is solid (hard) and thick (typically 30μ”), thus more ideal for the abrasive effects of constant PCB usage.