Power selection for soldering irons
The use of soldering iron power is too large, it is easy to burn components (generally diode, triode node temperature exceeds 200 ℃ will burn) and make the printed wire from the substrate; use of soldering iron power is too small, the solder can not be fully melted, the flux can not be volatilized, the solder joints are not smooth, not firm, easy to produce virtual welding. Generally, used for welding integrated circuits, printed circuit boards, CMOS circuits, decorative transistors, IC-type tape recorders, televisions, for general circuit experiments, generally 20W is appropriate, repair vacuum tube machines, such as gall bladder, old instruments, to 35W is appropriate, the external heat type is 45W, welding large transformer wiring, grounding trunks on the metal substrate, it is the use of the internal heat type 50W, external heat type 75W, there are some occasions with more power.
There are a variety of shapes of the soldering iron head, the main point of choice is that can often maintain a certain amount of solder, can quickly and effectively melt the solder on the connector, does not produce false soldering, hitching, hanging tin, soldering joints without burrs, do not burn the board and components. The machine on the soldering point of the new mouth bright, then the soldering iron head dipped in tin cross-section can be larger, with a flat or oval head, fast heat transfer natural operation. Thick oxidized layer of tin surface, the soldering iron tip is relatively more pointed, easy to break through.
Components with high density, need to use the corresponding thin ferrous alloy head to avoid burns and tin. Installation and disassembly of IC blocks, often use a special shape of the soldering iron tip. Sometimes because of welding, and to avoid scalding the plastic parts, the choice of curved iron head. Of course, it also depends on the operating habits and hobbies of each person.
According to the choice of the power of the soldering iron
(1) welding small power resistive components, transistors, integrated circuits, printed circuit board pads or plastic wires, it is appropriate to use 30 ~ 45W external heat or 20W endothermic soldering iron. Application of 20W endothermic soldering iron is best.
(2) welding general structure of the product welding point, such as wire ring, wire claw, heat sink, grounding pads, etc., should be used 7 5~100W soldering iron. (3) For large-scale welding points, such as welding metal frame joints, welding pieces, etc., it is appropriate to use 100 ~ 200W soldering iron.
