Printed circuit board or printed circuit board (English: printed circuit board – PCB), sometimes referred to as printed circuit board, is a circuit board that uses a printing method to shape conductive circuits and component connection points on the substrate insulation.

Printed circuit board

Manufacturing printed circuit boards is an important step in the process of manufacturing electronic circuit boards. In the past, making printed circuit boards was separate from circuit diagrams. Today the computer-aided design and production system (CAD-CAM) ensures automatic continuity from circuit diagram design to assembly, mitigating human intervention and producing cost-effective products. low.

Currently there are 2 printed circuit generation technologies.

The most common and consistent technology associated with the PCB name, is the fabrication of boards with copper conductive circuits on hard insulating panels with bakelit, or high-quality FR-4 (Flame Retardant 4) substrates often call colloquially. is “fip”. The original circuit board is an insulating sheet with copper coating. The image of the circuit is drawn first, and it is put on the surface of the layer by the printing process, in the way of printing or printing the net, creating a water-proof coating.

Then corrode or peel off the unused copper layer, and the rest are circuits.

New technology is electronic printing (Printed electronics) for inkjet and / or laser printing, printing with printheads and appropriate materials to create layers, conductive circuits, resistors, capacitors, transistors, … on hard or film base. Inkjet printing can include insulating spraying to isolate the electrical conductors at the position they squeeze over each other. This is a more true printing technology but is not considered typical for printed circuits. This technology is used in making many types of circuits, and sometimes it is also done on PCB semi-finished circuit boards to create circuit connections or components. This technology is highly automated and produces low cost products.

Today printed circuits are designed on computers using specialized electronic design software such as: Orcad, Altium, Proteus, PADS, Sprint layout, Eagle … These software support design from circuit diagram Principle to Layout. The main steps in computer design include:

• Electronic circuit design through electronic design automation tools (EDA, Electronic design automation).
• Determine the size and pattern of the PCB board and box suitable for the circuit system.
• Locate components taking into account their size and heat dissipation, and heat sinks if available.
• Determine the number of PCB layers depending on the complexity of the circuit, the layout of the ground array (Ground), the pathway membrane (Power) and the signal line array. To minimize electromagnetic interference between components and signal lines, high frequency signals need to be routed in the inner layers between the ground and / or the source array.
• Determine the line impedance by using dielectric layer thickness, copper thickness and copper width. In case of different signals, it is necessary to take into account the separation of roads.
• Microstrip forms, stripline or dual stripline can be used to route signals. Electronic design automation tools often allow automatic verification of signal connection, ground connection and power
• Export Gerber files to control circuit board processing machines.

If the circuit diagram operation is performed in accordance with the required syntax, the user can run a simulation of error checking, as well as use it for automatic circuit layout in the printed circuit board.

When designing printed circuit boards, designers need to understand the size of objects, arrange and arrange components to best suit on a circuit board, while avoiding mutual interference between them. Support for printed circuit design is a library of components, including sizes, footprints, etc. for users to call out in layout space on the circuit board. The success of a design depends on user experience, and in many cases it is necessary to do many new versions to achieve the desired version.