Plated through-hole (PTH) and via are two different types of holes used in printed circuit boards (PCBs).
A plated through-hole (PTH) is a hole drilled through the PCB and lined with a conductive material such as copper. The lining is then plated with a metal like tin or gold to create a connection between the different layers of the PCB. PTHs are commonly used to connect electrical connections between different PCB layers or components on the board.
A via, on the other hand, is a hole drilled through a single layer of the PCB and plated with a conductive material like copper. Vias are used to connect different parts of the same layer of the PCB. They are also used to connect components on the same board side. Vias can be through-hole vias or microvias, which are tiny holes with a very small diameter used in high-density circuit design.
PTHs and vias are holes used in PCBs for conducting electricity. PTHs pass through the entire board and connect different layers. In contrast, vias are used to connect different parts or components on the same PCB layer.