What is the Primary Side also known as in PCB terminology?

In PCB terminology, the Primary Side is commonly referred to as the Component side. This side of the printed circuit board is where the electronic components, such as resistors, capacitors, and integrated circuits, are primarily mounted. It is considered the "top" side of the PCB, especially in relation to the typical assembly process, where components are placed and soldered onto this surface.

The terminology is significant because it helps to standardize communication about PCB design and assembly. Understanding which side is referenced as the Primary Side is crucial for ensuring the correct placement of components and for the inspection processes that follow manufacturing. In contrast, the other options refer to aspects of PCB configurations and assembly but do not accurately describe the Primary Side. For example, the solder source side and solder destination side might pertain to different soldering perspectives during assembly, while the secondary layer typically refers to internal layers in multi-layer boards, which are not visible from the surface.