Single-sided copper-clad PCBs are the simplest and most cost-effective type of printed circuit board, featuring a single layer of conductive copper on one side of an insulating substrate. This design is ideal for low-complexity electronic devices where component density is low and signal routing is straightforward.

The substrate is usually FR-4, though paper-based phenolics may be used for budget applications. The copper layer, typically 1 oz (35 μm) thick, is etched to form conductive traces, while the uncoated side serves as a mechanical support. Components are mounted on the copper side, with leads soldered directly to the traces. No plated-through holes are needed, simplifying manufacturing.

Single-sided PCBs are widely used in applications such as toys, calculators, power adapters, and simple sensors. Their low cost stems from minimal processing steps: the copper layer is laminated to the substrate, etched using photolithography, and coated with solder mask and silkscreen for component labeling. This simplicity also results in faster production times, making them suitable for prototyping and low-volume production.

Limitations include restricted design complexity, as all traces must be routed on one side, potentially leading to larger board sizes. They are not suitable for high-density or high-speed applications, as crosstalk between parallel traces can degrade signal integrity. Additionally, they cannot support components requiring interlayer connections, limiting their use in advanced electronics.

Despite these constraints, single-sided copper-clad PCBs remain essential in the electronics industry, offering an economical solution for simple circuits where performance requirements are modest. Their reliability and ease of manufacturing ensure continued demand in cost-sensitive applications.