Double-sided copper-clad PCBs are versatile circuit boards with conductive copper layers on both sides of an insulating substrate, connected by plated-through holes (PTHs) to enable interlayer electrical connections. This design offers a balance between complexity, cost, and functionality, making it widely used in consumer electronics, industrial controls, and automotive applications.

The substrate material is typically FR-4, a glass-reinforced epoxy resin, chosen for its good mechanical strength and electrical insulation properties. The copper cladding, available in thicknesses from 1 oz (35 μm) to 4 oz (140 μm), forms the conductive paths. Thicker copper is used for high-current applications, such as power supplies, while thinner layers are suitable for low-voltage signal routing.

PTHs are a defining feature, created by drilling holes through the board and plating them with copper to connect the top and bottom layers. This allows for more complex circuit designs than single-sided PCBs, as components can be placed on both sides, reducing the board size. Solder mask is applied to both surfaces to protect copper traces from oxidation and prevent unintended solder bridges during assembly.

Double-sided PCBs offer several advantages. They provide greater design flexibility, enabling more components to be packed into a smaller area without overlapping traces. This is particularly useful for devices like Arduino boards, LED drivers, and small appliances. The ability to route high-current and low-signal traces on separate sides minimizes interference, improving overall performance.

Manufacturing costs are higher than single-sided PCBs due to the additional processing steps (e.g., PTH plating, double-sided etching) but remain lower than multilayer boards. This cost-effectiveness, combined with increased functionality, makes double-sided copper-clad PCBs a popular choice for medium-complexity electronic systems.