Gold fingers are the row of plated contacts along a board edge that mate with a card-edge connector. They are electroplated with hard, cobalt-hardened gold over nickel, often around 0.8 micrometres or more thick, so they survive repeated insertions, and the edge is bevelled, commonly 20 to 45 degrees, to ease insertion. Plating bars that feed current during plating are routed off afterwards, and no mask or silkscreen may stray onto the contact area.
Bevel the edge at 30 degrees and give the gold fingers 30 microinches of hard gold, it lives in a test socket all day.
Also heard as
- edge fingers
- edge contacts
Related terms
Surface finish
Final coating on exposed copper pads that stops them oxidising and decides how well they solder.
ENIG
Electroless nickel immersion gold: flat surface finish of nickel topped with a very thin layer of gold.
Plating
Electrochemical deposition of copper or other metals on a board, building hole walls and surface conductors.