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29
Mastering the Art of Soldering
Diagram of Surface Mount Component
4.7.2 What are Surface Mount Devices?
SMD or surface mount devices are those with components that are soldered onto the
surface of a PCB in surface-mount technique. The electronic components are usually small
in size as compared with their through-hole technology counterpart and are often square,
rectangular or oval in shape, and with very small footprints.
In contrast with those used in THT, SMD components do not have wire leads or terminals
that is inserted through a PCB. Instead, SMDs components have smaller leads or pins or
sometimes no leads at all and are mounted or soldered onto the surface of the circuit board.
Due to smaller sizes of SMD, soldering and desoldering of these components require high
level of soldering precision.
PCB with surface-mount components
4.7.3 How to Solder SMT Components: Preparations and Steps
In soldering SMT components, same preparations just like what is discussed in THT
soldering will be done (preparing soldering kit, PCB and SMT components). But this time,
maybe you will need to use
tweezers
often to hold the smaller SMT components. You may
need to use additional tools like the
magnifiers
and light (not included in the kit) to magnify
and see clearly the parts you are working on since the components are very small. You may
also need to use
flux
(not included in the kit) to clean the pad so that solder will stick
properly.
In soldering surface-mount (SM) components, the general steps are the following:
1.
Add flux to the PCB
2.
Solder the SM component on one side
3.
Solder the other side of the SM component
