Why PCBs are usually green?

In the field of PCB manufacturing, the color green is the most common and iconic choice, which leads many to wonder: why is green chosen as the primary color for Printed Circuit Boards (PCBs)? Behind this choice lie deep historical and technical reasons. Let's delve into the intriguing background.

History and Origin of Green PCBs

The history of PCB manufacturing dates back to the early 20th century when electronics technology was in its infancy. Early PCB production was a manual process, with different manufacturers using varying materials and methods. However, with the rapid growth of the electronics industry, a standardized way of producing circuit boards was needed, driving the evolution of PCB manufacturing processes.

In this process, the use of solder mask became increasingly significant. Solder mask is a protective layer applied to the surface of the PCB, aiding in preventing unnecessary soldering and enhancing the reliability of the circuit board. Green was one of the earliest and widely adopted colors for solder mask.

Advantages and Selection of Green Color

The choice of green as the preferred color for PCBs is based on several advantages:

1. Visibility and Contrast: Markings in white or black are highly visible against a green background, which is crucial during manufacturing and assembly processes. Green is one of the colors most sensitively perceived by the human eye, assisting electronics engineers and manufacturers in accurately identifying components and connections.

2. Material Stability: Green solder mask typically remains stable even at high temperatures, a critical feature during manufacturing and soldering processes. This stability ensures consistent performance across various stages of manufacturing and assembly.

3. Historical and Conventional: With the development of PCB manufacturing processes, green PCBs gradually became the standard, and this convention has persisted over time. This has made green the default expectation for many when it comes to PCBs.

4. Brand Recognition: Green PCBs have become a hallmark of electronic devices, aiding people in easily identifying the origin and brand of products.

While green is the most common color for PCBs, advances in technology have introduced other colors for PCBs, such as red, blue, black, and more. Different colors can reflect varied PCB purposes, design characteristics, and manufacturing standards. Nevertheless, green remains one of the most widespread and frequently used colors for PCBs due to its fusion of advantages like visibility, convention, and material stability. Whether in the past, present, or future, green PCBs will continue to play a crucial role in the electronics industry.