PTH is a metallized hole. Generally, the PTH hole of the circuit board has two purposes. One is used for welding traditional dip parts. The diameter of these holes must be larger than the diameter of the welding feet of the parts. Insert into the hole.

Another relatively small PTH, usually called via (via), is used to connect and conduct copper foil lines between two or more layers of a circuit board (PCB), because the PCB is made of Many copper foil layers are stacked and accumulated, and each layer of copper foil (copper) will be covered with an insulating layer, which means that the copper foil layers cannot communicate with each other, and the signal connection is via via, So Chinese will call it (via hole).

NPTH is a non-metallized hole, and there is no copper inside the hole. The electrical isolation through hole refers to the top and bottom layers of the PCB board. Similar holes also have blind holes and buried holes, and the through holes can be PTH or NPTH, according to specific needs. Depends. For example, holes for connecting wires require PTH, and for fixing functions, such as screw holes, may be NPTH.