According to IPC-A-610, what is one necessary characteristic of reliable solder connections?

Reliable solder connections are critical in electronic assemblies for ensuring functionality and longevity. One necessary characteristic is proper wetting. Wetting refers to the ability of solder to spread and adhere to the surfaces being joined, creating a strong mechanical and electrical bond.

When solder wets properly, it shows that the surfaces are clean and compatible with the solder material, which significantly affects the joint's quality. Proper wetting minimizes the risk of defects such as cold solder joints, which can lead to intermittent connections and failure over time. Ensuring that solder flows well into the joint and makes good contact with the components and the PCB pads enhances the reliability of the connection.

While shiny solder can be an indicator of good quality, it is not a standard requirement for reliability. The thickness of the solder and its color also do not directly correlate to the effectiveness or reliability of the connection, emphasizing that proper wetting is the critical factor in establishing dependable solder joints in electronics.