The long and short golden finger is designed to have a power-on timing difference when the PCB board is plugged in and unplugged. For example, when the golden finger is removed, the short finger is disconnected from the power supply, which plays a protective role. Generally, when the golden finger is inserted, if the short finger is not inserted in place, the power supply will not supply power to avoid power surge damage to the golden finger product.

There are also some devices, for example, the length of the four pins of the USB interface is also different. One of the two long golden fingers on the left and right is connected to the power supply and the other is grounded, and the two short fingers in the middle are responsible for data transmission. In this way, when the U disk is inserted into the machine, ensure that the power is turned on before the data can be transmitted, which is also for the normal access and protection of the equipment. If the long and short golden fingers are made into equal-length golden fingers, the protective effect will be lost, and reliability problems will occur.

The factory routinely removes the long and short gold finger leads by using a secondary etching process. To put it simply, the circuit is etched for the first time, and the circuit part is covered with dry film or blue glue, and the gold finger The area is plated with gold, and then all areas are covered with dry film to expose only the part of the gold finger leads, and the leads are etched.