Green PCBs are the most common type of printed circuit boards, distinguished by their green solder mask—a protective layer applied to the substrate to insulate copper traces, prevent short circuits, and resist environmental damage. The green color comes from epoxy resin mixed with a green pigment (typically chromium oxide), though the base material of the PCB itself is usually fiberglass-reinforced epoxy (FR-4), a cost-effective and versatile substrate.

The green solder mask serves multiple critical functions: it protects exposed copper from oxidation, ensures solder only adheres to designated pads during assembly, and provides mechanical strength to the board. This mask is applied using processes like screen printing or photolithography, creating precise openings for components, vias, and test points. While green is the standard color (chosen for its high visibility during inspection and compatibility with automated optical inspection systems), other colors (red, blue, black) are available, but green remains dominant due to industry familiarity and lower production costs.

Green PCBs are widely used in consumer electronics, such as smartphones, laptops, and home appliances, where cost and reliability balance are key. They support standard operating temperatures (-40°C to 120°C) and are compatible with through-hole and surface-mount components. The FR-4 substrate offers good electrical insulation and mechanical stability, making green PCBs suitable for low to medium complexity circuits.

Manufacturers often optimize green PCBs for mass production, leveraging mature fabrication processes to reduce lead times and costs. Despite their ubiquity, they can be customized with varying copper thicknesses (1oz to 4oz) and layer counts (2 to 16 layers) to meet specific power and signal requirements. Their combination of affordability, versatility, and reliability makes green PCBs the backbone of modern electronics manufacturing.