Through Hole technology is a technique for building electronic circuits in which the pin-through-hole (PTH) components are embedded through gaps penetrated into printed circuit boards (PCBs). The closures, or leads, are then appended to pads on the opposite side with molten metal solder using wave soldering or reflow soldering equipment. This process is also called through hole assembly.
Through Hole technology supplanted early electronics assembly techniques, for example, point-to-point development. From the second era of PCs in the 1950s until the point when the surface-mount technology ended up prevalent in the late 1980s, each part on a typical PCB was a through hole component.
While through hole mounting gives more grounded mechanical bonds than surface-mount technology procedures, the extra drilling required makes the boards more costly to create.
It also limits the available routing area for signal traces on multilayer boards since the holes must pass through all layers to the opposite side.
Hence, through-hole mounting is typically held for bulkier parts, for example, electrolytic capacitors or semiconductors in substantial bundles that require extra mounting quality to bear physical pressure.
Through-Hole Technology Pros and Cons
|Easier prototyping||Higher board cost due to drilling|
|Strong physical connections||Takes up more board real-estate|
|Heat tolerance||Assembly process is more involved|
|Power handling capability||Slower speeds|
Table source: https://resources.altium.com/pcb-design-blog/why-use-through-hole-technology-in-pcb-design