What are the considerations when choosing the power of a soldering iron?
If the power of the soldering iron is too high, it is easy to burn the components (usually the junction temperature of the diode and transistor exceeds 200°C) and cause the printed wire to fall off the substrate; if the power of the soldering iron is too small, the solder cannot be fully melted. , the flux cannot evaporate, the solder joints are not smooth and firm, and it is easy to produce false soldering. Generally, it is used for welding integrated circuits, printed circuit boards, CMOS circuits, decoration transistors, IC radios and recorders, and televisions. It is generally used for ordinary circuit experiments. Generally, 20W is suitable for repairing vacuum tube machines, such as tube amps and old instruments. , 35W is suitable, and external heating type is 45W. For welding large transformer wiring and grounding trunk lines on metal base plates, internal heating type 50W and external heating type 75W are used. There are also some occasions with higher power.
There are various shapes of soldering iron tips. The key points of selection are that they can always maintain a certain amount of solder, can quickly and effectively melt the solder on the joints, and do not produce false solder, soldering, or hanging tin. The solder joints have no burrs and are not burned. Boards and components. If the solder joints on the machine are new and bright, the soldering iron tip can have a larger tinned cross section and use a flat or oval tip, which can transfer heat quickly and operate smoothly. The oxide layer on the tin surface is thicker, and the soldering iron tip should be relatively pointed to facilitate breakthrough.
The density of components is high, so it is necessary to use correspondingly tapered ferroalloy heads to avoid burns and soldering. When assembling and disassembling IC blocks, special-shaped soldering iron tips are often used. Sometimes, because it cannot be soldered and to avoid burning plastic parts, a curved soldering iron tip is used. Of course, it also depends on everyone's operating habits and hobbies.
There are many kinds of power of electric irons, the smaller ones are 15 watts and 20 watts, the larger ones are 200 watts and 300 watts, and there are also pistol-type 500 watts. When performing welding work, the power of the soldering iron must be determined according to the welding object, and sometimes the power of the electric iron must be selected according to the climate season (winter, summer). When welding electronic components, just use 15 to 20 watts. If you use 500 watts, once the soldering iron is put down, it will be a black hole, which is of course not good.
Whether the power selection is appropriate mainly depends on the melting and flow of solder. This process does not take more than three seconds. If it is too long, it will damage the electronic components. If it is too short, the welding will not be reliable and the solder joints will not be smooth.
Generally, when welding small components such as resistors, capacitors, transistors, and manifolds, it is advisable to use a 20-watt soldering iron. In winter, increase the power level by 25 watts. When welding large-foot components such as heat sinks, transformers, shields, or grounding large-area copper plates, 35 watts to 40 watts should be used. Therefore, the power of the soldering iron must be appropriately selected according to the object being welded. There is no such thing as high power or low power.
