Printed circuit boards (PCBs) appear in almost every type of electronic device. If there are electronic parts in a certain device, they are also mounted on PCBs of different sizes. In addition to fixing a variety of small parts, the main function of the PCB is to provide the electrical connection between the upper parts. With more and more complex electronic devices, more and more parts are needed, and the lines and parts on the PCB are becoming more and more intensive. The standard PCB looks like this. Bare boards (without parts on top) are also often referred to as “Printed Wiring Boards (PWBs).”

The substrate of the board itself is made of a material that is insulated and insulated and hard to bend. The fine line material that can be seen on the surface is copper foil. The original copper foil is covered on the entire board. During the manufacturing process, part of the copper foil is etched away, and the remaining part becomes a mesh-like fine line. These lines are called conductor patterns or wires and are used to provide circuit connections to parts on the PCB.

To fix the parts on the PCB, we soldered their pins directly to the wiring. In the most basic PCB (single panel), parts are concentrated on one side, and wires are on the other side. As a result, we need to make a hole in the board so that the pin can pass through the board to the other side, so the pin of the part is soldered on the other side. Because of this, the front and back of the PCB are called Component Side and Solder Side, respectively.


If there are some parts on the top of the PCB that need to be removed or replaced after the production is complete, the part will be installed with a socket. Since the socket is directly welded to the board, parts can be detached arbitrarily. Seen below is the ZIF (Zero Insertion Force) socket, which allows the part (in this case, the CPU) to be easily plugged into the socket and removed. The lever next to the socket can be fixed after you insert the part.

If we want to connect two PCBs to each other, we generally use an edge connector commonly known as the “gold finger.” The gold finger contains many exposed copper pads, which are in fact part of the PCB layout. Usually, when connecting, we insert the golden finger on one of the PCBs into the appropriate slot on the other PCB (commonly called the expansion slot Slot). In a computer, such as a display card, sound card, or another similar interface card, all of them are connected to the motherboard through a golden finger.

The green or brown color on the PCB is the color of the solder mask. This layer is an insulating protective layer that protects the copper wire and prevents parts from being soldered to the wrong place. A layer of silkscreen is printed on the solder mask. Usually, the text and symbols (mostly white) are printed on it to indicate the position of each part on the board. The screen printing surface is also called a legend.


Alice Lu