PCB Bolg - The difference between npth pcb and pth pcb

PTH PCB board (Plated Through Hole)

NPTH PCB board (Non-Plated Through Hole)

The key difference between PTH pcb board and NPTH pcb board lies in whether the hole walls are plated with copper!

PTH: The hole walls are copper-plated, conductive, and connect circuits across different layers.

NPTH: The hole walls are bare and insulated, serving only a mechanical structural function.

What is the purpose of NPTH pcb?

NPTH pcb appears large and “non-conductive”—what exactly is it for?

In fact, the role of NPTH is far from simple:

•       Used for securing screws (connecting chassis, heat sinks, and other structural components)

•    Anchoring external interfaces/connectors

•    Serving as positioning holes for test fixtures

Schematic showing typical NPTH applications for screw holes and corner positioning holes

Generally, NPTHs feature larger diameters and do not require electrical continuity within the board. Their primary functions are structural reinforcement or installation convenience.

PTH Function: The Core Element of Electrical Connectivity

PTHs serve a completely different purpose, acting as the critical means for achieving electrical connections between layers on the board.

Common uses fall into two categories:

✅ Used for soldering through-hole components (e.g., DIP devices)

•    Typically resistors, capacitors, inductors, and other pin-type components

•    Hole diameter must exceed pin diameter to facilitate insertion and soldering

Figure 3: Soldering through-hole components via PTH

✅ Signal continuity (commonly called “Via”)

Although no Via diagram is provided in the documentation, in actual PCBs, small PTH holes (Vias) connect copper traces across different layers, making them indispensable in high-speed/high-density designs.

PS: A Via is essentially a smaller, denser form of PTH.