PCB circuit boards come in a wide variety of types and can be classified according to board material, structure, manufacturing process, and other criteria. By structure, PCB circuit boards can be divided into single-sided PCBs, double-sided PCBs, and multilayer PCBs. Common multilayer boards are typically four- or six-layer boards, while more complex multilayer PCBs can have over ten layers. This article will introduce you to several common types of PCB boards in detail.

1. Single-sided PCB

A single-sided PCB is the most basic type of circuit board in the PCB industry. As the name suggests, a single-sided PCB has conductive traces on one side and component leads on the other. In the early days, single-sided PCBs were widely used across various industries. However, due to their high wiring requirements—each trace must have its own dedicated path without any crossings—single-sided PCBs gradually lost popularity as they became less stable and performed inferiorly when dealing with complex circuit layouts. Consequently, the industry began shifting toward double-sided PCBs. As a result, the usage and production rate of single-sided PCBs have been steadily declining. Currently, single-sided PCBs are still commonly used, particularly in power supply boards.

2. Double-sided PCB

A double-sided PCB is a printed circuit board with wiring on both sides of the substrate. A key feature of a double-sided PCB is the presence of plated-through holes, which connect the conductive traces on both sides to form a complete circuit. The wiring on a double-sided PCB can intersect and cross over each other—this is the biggest difference between double-sided and single-sided PCBs. Double-sided PCBs are better suited for complex circuits and have a wider range of applications. The cost difference between single-sided and double-sided PCBs is relatively small; unless there are specific requirements, most industries will prefer double-sided PCBs, since they offer superior performance and stability compared to single-sided PCBs.

3. Multilayer PCB board

Simply put, a multilayer PCB is created by alternately stacking multiple single-sided and double-sided boards, separated by insulating materials and secured with a positioning system, and then interconnecting the circuit traces to form a multilayer circuit board. For example, you can start with a double-sided board as the inner layer and two single-sided boards as additional inner layers, using specialized techniques to create a four-layer PCB. Multilayer boards offer greater design flexibility and provide more stable and reliable electrical performance. Currently, four- and six-layer boards remain the most widely used in various industries, while the consumer electronics sector tends to favor higher-layer PCBs. Although multilayer boards have clear advantages over double-sided boards in terms of performance, stability, and noise reduction, many companies and engineers still prefer double-sided boards primarily due to cost considerations.