What is THT (Through Hole Technology)? Through-hole components, soldering methods (wave, selective, manual) and when to use THT instead of SMD.
What is THT?
THT stands for Through Hole Technology. Component leads are inserted through holes in the PCB and soldered on the opposite side. While SMD dominates modern electronics, THT remains essential for applications requiring mechanical strength and high current capacity.
Typical THT Components
Common THT components include: connectors (USB, RJ45), relays, transformers, large electrolytic capacitors, power semiconductors (TO-220/TO-247), inductors, and fuse holders. THT is preferred when components face mechanical stress or need to dissipate heat.
THT Soldering Methods
Three main methods: Wave soldering for boards with many THT parts, selective soldering for few THT parts alongside SMD, and manual soldering for prototypes and repairs.
When to Use THT vs. SMD
Choose THT for mechanical stress, high currents, heat dissipation, and vibration environments. Choose SMD for compact designs, series production, and standard components. Most assemblies combine both technologies.
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