What is a printed circuit board? Structure, terms and applications to know

printed circuit board 2

Printed circuit boards are an indispensable electronic component in today’s electronic devices and industrial machines. So what is a printed circuit board? What is the structure of the printed circuit board? What function does it perform? The following article by Thetech will help you answer all questions related to this type of circuit.

What is a printed circuit board?


A printed circuit board (PCB) is a type of printed circuit board. This printed circuit board will contain conductors and electronic components such as ICs, capacitors, inductors, resistors, etc.

The printed circuit board itself is not conductive but relies on paths and buffering points on the surface. The role of the paths is to connect and transmit electrical signals between points located at different locations on the printed circuit board.

printed circuit board 1

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What is the difference between a PCB and a PCBA?

Many people often confuse printed circuit boards with printed circuit board A. So what is the difference between these two types of circuit boards? Printed Circuit Board A (Printed Circuit Board Assembly) is the name used to refer to the finished printed circuit board. That is, the printed circuit board is now fully soldered with the necessary components such as resistors, ICs, capacitors, etc. And the printed circuit board is just an empty circuit board; it has not yet installed any components.

printed circuit board 2

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Printed circuit board A usually has undergone manual soldering or uses SMT and reflow soldering technology to create a complete connection between components and the printed circuit.

The components that make up the printed circuit board

Printed circuit boards are composed of many different layers; each layer will perform a separate function, connected by heat or adhesive to form a unified whole.

FR4 Substrate

FR4 is known to be fiberglass. This is the most common and basic substrate material on many printed circuit boards. The FR4 substrate will help the printed circuit board have good rigidity and thickness, limiting breakage and cracking. At the same time, FR4 glass fiber also ensures insulation on the circuit board.


The second layer in a printed circuit board (PCB) is a thin layer of copper, which is laminated with heat and an adhesive. This copper layer acts as a conductor in the circuit. The thickness of the copper layer is variable and determined by weight. In particular, how much copper to cover will depend on the function and design of the circuit.

printed circuit board 3

Solder Mask

The next layer on top of the copper layer is the solder mask layer. This layer plays the role of creating a characteristic color for the printed circuit board, usually green, but it can also be other colors, depending on the manufacturer. This solder mask layer will be covered over the entire circuit (except for the component feet to be soldered); its purpose is to separate the component legs from the surrounding circuits, prevent oxidation, and help the welder. easily adjust the small SMD components to the correct position to be soldered.


The last layer covered on the printed circuit board is the Silkscreen layer, also known as the ink layer. This layer will have a letter, number, or symbol to help the mechanic know where to attach which components and how much value is appropriate. The Silkscreen layer is usually white, but the manufacturer can also use any color to make it stand out and be easy to see.

Terms to know about printed circuit boards

After learning about the structure of printed circuit boards, you also need to know some more terms related to printed circuit boards, as follows:

  • Annular rings are copper rings plated around a hole in the PCB.
  • Drill: This is the place to screw or locate the connector.
  • Fingers are metal pieces that are in contact along the edge of the printed circuit and have the effect of creating a connection between two circuit boards.
  • Pad: This is the place where components will be soldered on the surface of the PCB.
  • Panel: a large circuit board consisting of many small boards inside
  • Mouse bites: The technique of separating printed circuits from the large board (Panel) using a number of drills located close to each other to create a weak point to separate the PCB from the Panel without fear of damage or a circuit break.
  • Paste stencil: thin stencils, metal or plastic, designed according to the paths of the PCB to help fix solder paste in place.
  • Plane: a continuous block of copper on the circuit board, defined by contour, not by path.
  • Plated through hole: The technique of plating holes in a circuit from one side to the other to create connection points for through-hole components through signal transmission.

printed circuit board 4

Applications of printed circuit boards in life

Printed circuit boards are applied in many different industries and fields, such as:

  • Medical: Printed circuit boards eliminate the complexity of wires and connectors in the system, making medical equipment more compact and lighter.
  • Aerospace: Printed circuit boards are used in boards, control devices, operating systems, and safety systems.
  • Military: PCBs are used to control robots, as a navigation system, and as a missile aiming system.
  • Industry: Printed circuit boards help automate machines, enhancing work efficiency.

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Above is all the information about PCB circuits and PCB structure. Hopefully, through this article, you have been able to better understand this circuit board. If you need any further advice, do not hesitate to contact a reputable company that distributes soldering materials and electronic components—The tech—for answers!

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