The 28 pin board can take an 8 pin and 14 or 16 pin. The point of this explanation is to let you know that the temperature of the solder bath is strictly controlled and the solder-time is kept to a minimum.
The devices are placed on the board and held in position with glue and when the board is exposed to high temperature air, the solder on each of the lands is melted and forms a bond with the leads of the component. The pin-out corresponds exactly to the NPN circuit-symbol.
When it comes to production costs, SM becomes the cheaper alternative when very large quantities are ordered. In the meantime, you can start with TE surface-mount prototyping boards and develop your skills in this area. Always keep chip capacitors in their «carrier» until required. Most soldering irons are much hotter than this and so your soldering time must be kept as short as possible. The following SM prototyping boards are available and these are mainly designed for SM IC’s. See below for PC board prices.
You may want to use chips that can be inserted and removed (such as microcontroller chips) or air spaced coils (for high frequency oscillators) or a potentiometer with a knob. After a small amount of practice, you will find SM assembly the smartest way to go and many Talking Electronics projects are partially or fully surface mount.
Once you get the circuit working you can tidy up the layout and reduce the size of the board. When it comes to SM, the board is considerably smaller than a conventional design and it is cheaper to produce as it does not require drilling. Another method of soldering surface-mount devices uses a shallow bath of molten solder.
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