Single-sided PCB board: The solder joints are concentrated on 1 facet, and components are generally inserted on one other facet. Some products continue to have SMD components about the copper-clad facet. Double-sided board: Both sides could be format, and the two can have plug-in components or SMD components. Which means https://connernrstu.actoblog.com/32009642/four-layer-inner-and-outer-layers-2oz-copper-thick-pcb-circuit-board-things-to-know-before-you-buy