What is the primary side of a PCB defined as?

The primary side of a printed circuit board (PCB) is defined as the side that is designated as such on the master drawing. This side typically contains the majority of the critical components and connections that are essential for the PCB's functionality. Most design specifications outline this primary side to avoid confusion during assembly and inspection processes.

Recognizing the primary side as defined on the master drawing is crucial for several reasons. It establishes a reference point for alignment when soldering components, ensures that components are placed correctly, and aids in inspecting the assembly for conformity to design requirements. Understanding this definition is important in the context of electronic assembly, as it directly impacts the quality and reliability of the finished product.