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Lanes of copper on a printed circuit board, for carrying current or signals between pads

Traces are long, thin lanes of copper on a printed circuit board (PCB). Traces typically connect two pads on the PCB, creating a conductive path between them. Like any conductors, traces exhibit resistance, inductance, and capacitance, and all these factors may matter when laying out a PCB. Perhaps most notably, the width and thickness of a trace determines its current-carrying capability.

Trace width is often spec'd in mils (thousandths of an inch), and trace thickness is often spec'd in ounces of copper per square foot.

Traces are typically distinct from copper planes, pours, areas, or polygons.

Traces typically do not connect at right angles to other traces.