Through-hole is a method used in electronics for mounting components onto a printed circuit board (PCB). In this technique, components have leads that pass through holes drilled in the PCB and are soldered on the opposite side. This provides a strong mechanical connection and is commonly used for larger components. This method contrasts with surface-mount technology (SMT), where components are placed directly on the surface of the PCB. Through-hole technology is often preferred for its durability and ease of handling, making it suitable for prototyping and applications requiring robust connections.