PCB Gold Fingers – What Are They?


PCB Gold Fingers – What Are They?

We all by now know what PCBs are – those small chip-like green and golden things that help any and every electronic device perform the way they do. Now, what are “Gold Fingers”? While they may sound something pretty or tasty, they are nothing but those connectors at the edge of the PCBs. Just because they resemble fingers and are gold in colour, there are known as gold fingers.

Why are gold fingers made?

Gold fingers are there on PCBs for a reason. The basic function of these gold fingers is to help connect a secondary PCB to the motherboard of an electronic device like computers, smartphones, smartwatches, etc. Thus, gold fingers make it possible to connect different circuit boards, thus helping them to communicate. From the power source to the device, signals must pass between several contacts for a given command to be enacted; and gold fingers help with just that. Once a command is pressed, the signal will pass between one or more circuit boards before being read with the help of these gold fingers. Apart from this, gold fingers also help protect the PCBs from wear and tear.

Why is gold used?

Now, you may wonder that when copper is used all along every PCB assembly from India, why gold is used for these gold fingers. The main reason behind this is the material’s superior conductivity. However, the process involved in the plating of gold involves a number of meticulous steps to ensure that the PCB is properly equipped to conduct error-free signals. The PCBs are also passed through a number of inspections and defect tests to ensure that all the fingers and slots fit just perfectly.

Which materials are used for gold fingers?

Gold fingers can be made of electroplated nickel gold or immersion gold.

Electroplated nickel gold – This material is used to achieve properties of super conductivity, oxidation resistance, and wear resistance. Thus, it is used in PCBs that require frequent plugging and de-plugging, or those that require frequent mechanical friction.

Immersion gold – This material is used in high precision PCBs to offer super conductivity, flatness, and solderbaility. The PCBs that require low wear resistance can opt for immersion gold.

Considerations to be made

There are lots of considerations that need to be made for the gold fingers. Some of the most important ones are –

  • The gold fingers need solder masking window treatment.
  • The gold fingers need to be chamfered at 20°, 30°, or 45° angles.
  • The gold fingers need to be kept away from the copper used on the rest of the board.

A lot more goes into the designing of PCBs and every other component of the board; let alone the gold fingers. You must get in touch with a professional manufacturer when you want a PCB assembly from India for your application. One such place is Miracle Aerospace, where you can get the best quality μBGA and surface mount PCB assemblies, for even the most critical applications like military and aerospace.