Through-hole assembly

  In through hole pcb assembly , the components are mounted on the PCB board by inserting their leads/terminals in holes that are already drilled through the PCB board. These terminals are then soldered manually or through reflow soldering  to hold the component in place and connect it to the conductive path. One key thing to note about Thru-hole assembly is that it is not very efficient for multi-layer PCBs as it takes up board space on every layer. As a result, this type of assembly is usually found on single-layer PCBs.

  The Through Hole Soldering technique was the primary method which was used to add components on a PCB till the emergence of Surface Mount Technology. Components soldered using the Surface Mount Soldering technique (SMT) do not have leads and can be directly mounted on the surface of the PCB. In addition to this, the components of SMT are smaller in size and can be mounted on both sides of the board.

  Advantages of Through-hole PCB Assembly:

• Highly Reliable: Components mounted on a PCB Board using Through-hole assembly (THA) can withstand a high level of environmental stress as their terminals go through the drilled holes followed by soldering. This is the primary reason why Thru-Hole PCB boards are widely used in Military & Aerospace products as they tolerate extreme acceleration and collision scenarios.

• Manual adjustments can be performed easily: Defective components on PCB boards can be changed very easily. In other assembly processes like Surface Mount, it is not easy.