Läpijuotettavat

Läpijuotettavat, in English through-hole components, are electronic components designed to be soldered to a printed circuit board by inserting their leads through holes and soldering on the opposite side. The term is commonly used in Finnish to describe components compatible with through-hole technology (THT). This category is often contrasted with pintaliitettävät, or surface-mount components (SMT).

Typical läpijuotettavat komponentit include axial and radial resistors, capacitors with leads, diodes, transistors in through-hole packages, integrated circuits in dual in-line packages (DIP), inductors, connectors, and many power devices. These components generally use longer leads and larger footprints than SMT parts, which affects board layout and assembly.

Manufacturing and assembly for läpijuotettavat commonly involve manual or wave soldering processes. After insertion of leads into drilled PCBs, the joints are heated until solder flows and adheres to the pad and lead, forming a mechanical and electrical connection. They tend to provide greater mechanical robustness and are easier to replace or repair, which is advantageous in prototyping, educational use, or products requiring high power handling.

Design considerations for through-hole components include hole size and pitch, annular ring land dimensions, and board space consumption. While their use has declined in high-volume production in favor of SMT, läpijuotettavat remain prevalent in low-volume, hobbyist, and high-reliability applications where reworkability and mechanical strength are important. See also through-hole technology and surface-mount technology.