Multilayer PCBs are printed circuits produced up of greater than two layers. They need to as a result have a minimum of a few layers of conductive substance within the insulating material. On the other hand, double-sided PCBs only have two layers of conductive substance, the best and the bottom. https://hdi-pcb-for-electronic-pr18370.theisblog.com/31426910/not-known-factual-statements-about-4-layer-communication-pcb