Through-hole PCB assembly is a method used in electronics manufacturing where components with leads (wires or metal legs) are inserted into pre-drilled holes on a printed circuit board (PCB) and soldered to pads on the opposite side. This technique is one of the oldest methods of PCB assembly and continues to be used for its reliability and strength in creating durable connections.

Process of Through-Hole Assembly

THT Advantages & Disdvantages

Strong Mechanical Bonds: The leads passing through the board make the components less likely to detach, which is particularly valuable for applications subject to mechanical stress or extreme environmental conditions.

Higher Cost: The drilling and manual processing involved can make through-hole assembly more expensive compared to surface-mount technology (SMT). And if manual soldering + wave soldering, there will be need fixture(s), it’s not cheap.

Ease of Soldering: Through-hole soldering techniques are well-established, making them easier to inspect and repair because the solder joints are generally accessible.

Slower Production: Through holes components need handing soldering or insertion and wave soldering, it’s much slower compared to surface-mount technology (SMT). Another the labor cost is not cheap nowdays.

Power Handling: Through-hole components typically have higher power ratings than their surface-mount counterparts, making them ideal for high-power applications.

Limited Routing Space: The holes in the PCB can limit the available space for routing traces on multilayer boards, potentially complicating PCB design.


Through-hole technology is often chosen for devices requiring high reliability and robust components, such as in military and aerospace electronics, industrial machinery, and consumer electronics where durability and long service life are crucial. Despite the rising prevalence of surface-mount technology for its miniaturization benefits, through-hole assembly remains relevant for specific applications where reliability and strength are paramount.

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