PCB boards mainly divided into single-layer PCB boards and double-layer PCB boards, as well as multi-layer PCB boards. The most commonly used are single-layer PCB and double-layer PCB boards, and those with more than three layers are called multilayer PCB boards. For applications in different industries, there are different requirements for its shape, size, color, model, number of layers, etc. Now let’s introduce the difference between single layer, double layer and multi layer PCB boards in detail.