PCB Design, Layout, and Fabrication

Printed Circuit Boards (PCBs) are used to mechanically support and electrically connect electronic components via conductive pathways.
Schematic design is the first stage of PCB design. Here, components and connections are diagrammed without considering their physical layout.
Component placement is the next stage, where components are arranged on the board according to their interconnections.
Track routing then connects these components according to the diagram from the schematic design stage.
Routing can be done manually or automatically using Auto-Router tools; however, manual routing allows for more control and optimisation.
Considerations during PCB design should include expected current flow, signal interference and crosstalk, and thermal management.

Efficient PCB design reduces costs, increases reliability, and simplifies manufacturing. This often involves compact design, minimising trace lengths, and careful component selection.
PCBs can be single-sided, double-sided, or multi-layered, offering greater complexity and density for advanced electronics.
Power and ground planes are often used in multilayer boards for noise reduction and simplified routing.
High-frequency and sensitive components should be placed as closely together as possible to minimise the length of traces and potential for interference.
Important considerations include signal integrity, electromagnetic compatibility, and thermal performance.

PCB fabrication begins with selecting material, such as FR4 (Glass Reinforced Epoxy), based on factors like cost, rigidity, and thermal performance.
Etching process is used to remove unwanted copper from the board, leaving only the desired copper traces.
Once etched, a protective layer of solder mask is applied, followed by the application of a silkscreen layer for component identification and other information.
Boards then undergo a drilling process to create holes for through-hole components and vias.
Subsequent assembly process involves mounting and soldering of electronic components onto the PCB.

PCBs undergo various tests to ensure their reliability, functionality, and adherence to design specifications.
Continuity tests ensure that the desired connections are present and that undesired shorts do not exist.
Insulation tests or Hi-Pot tests evaluate the board’s resistance to high voltage and help identify any breakdowns in insulation.
Other functional tests may involve powering up the board and testing its operation in specific scenarios.
Automated Optical Inspection (AOI) is often used to quickly and reliably check for soldering defects, component placement, and other potential issues.

Different software suites are available for PCB design, including EAGLE, Altium Designer, and KiCad.
These programs often integrate schematic capture, board layout, and part suggestion.
Some also include auto-routing features, simulation capabilities, and libraries of common components.