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 advantagesover 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 balancebetween cost, performance, and quality, depending on the operating conditions and requirements of the electronic assembly.