Through-Hole Soldering Technology (THT) is a traditional but still widely used assembly technology in PCBA manufacturing, which involves inserting the leads of through-hole components into the through-holes of the PCB and then soldering the leads to the pads on the other side of the PCB, either by wave soldering or manual soldering. Despite the popularity of SMT, THT still has unique advantages that make it irreplaceable in many application scenarios. One of the most significant advantages is strong mechanical stability and reliability: the leads of through-hole components pass through the entire PCB and are soldered on both sides, forming a firm mechanical connection that can withstand greater mechanical stress, vibration, and impact. This makes THT particularly suitable for electronic products that work in harsh environments, such as industrial control equipment, automotive electronics, and aerospace devices, where component stability is crucial.

Another important advantage of THT is its ability to handle high-power and high-current components. Many high-power devices, such as power transistors, transformers, and connectors, have thick leads that can carry large currents, and THT can effectively fix these components and ensure good electrical contact. The through-hole soldering joints have a larger contact area, which reduces contact resistance and heat generation, improving the reliability of the circuit under high-power operation. In addition, THT has lower requirements on PCB precision and component tolerance compared with SMT, which makes the manufacturing cost lower in some small-batch production or prototype manufacturing scenarios. Manual soldering of THT components is also relatively simple and easy to operate, which is convenient for maintenance and repair: when a component fails, it can be easily desoldered and replaced without damaging the PCB. Furthermore, THT is compatible with a variety of component types, including some special components that cannot be made into SMDs, such as large-capacity electrolytic capacitors and mechanical switches, making it a complementary technology to SMT in PCBA manufacturing.