Through-hole Technology (THT)
Through-hole Technology (THT) is an assembly method used to connect active and passive electronic components to printed circuit boards ( PCBs ). In this process, the component leads are inserted through plated holes in the PCB and then soldered on the opposite side , either manually or using our ERSA wave soldering system or ERSA selective soldering systems . Due to greater mechanical stability and longer lifespan , THT still offers technological advantages over Surface Mount Technology (SMT) .
THT components are mainly used in high-current and high-voltage applications because they are mechanically more robust and therefore larger in size . Unlike SMT components, THT components are easier to assemble manually and can be tested without additional technical effort , making them particularly advantageous for prototyping and small-batch production .
The mechanical and electrical connection is particularly strong due to the through-hole mounting of components. This is beneficial for applications exposed to high currents, strong vibrations, or sudden impacts . However, higher component weight can be a disadvantage, as the PCB must support it.
THT remains a standard in safety-critical and certified applications , as many legacy devices and components are designed for this technology. Excluding THT in new developments can be problematic since SMT components behave differently and have higher surface temperatures .
While THT components offer robust construction and high performance , they also have disadvantages compared to SMT components . THT components are larger and more expensive , requiring more space and resulting in larger PCBs . Manual assembly of THT components has higher error rates than automated SMT assembly, particularly in handling and placement . Additionally, inspection and correction of THT solder joints slows down production and increases the need for rework in case of soldering defects .
In practice, a hybrid approach combining SMT and THT components is often used to achieve an optimal balance between cost, performance, and quality , depending on the operating conditions and requirements of the electronic assembly.