In the manufacture or repair of electronic devices, proper soldering is an important condition for ensuring their reliable operation. And if soldering resistors and capacitors is relatively simple, then some important rules should be followed when soldering transistors.
Instructions
Step 1
For soldering electronic components, choose a soldering iron with a power of no more than 60 watts, the optimal power will be 40 watts. Grind the tip of the soldering iron so that its size allows you to solder the individual legs of the miniature transistors. The blade width is quite convenient 3-3.5 mm. It is useful to have several soldering irons, differing in power and tip sharpening.
Step 2
Soldering bipolar transistors does not require any special precautions. Nevertheless, try not to overheat their terminals, the time for the soldering iron to touch the transistor leg should not exceed 3-4 seconds. If you solder the transistor instead of the punched one, heat the holes for the terminals with a soldering iron in turn and make holes in the molten solder with a needle. Carefully insert the legs of the transistor into the holes made and solder each leg.
Step 3
Pay close attention to the quality of the soldering. With the so-called "cold" soldering, that is, soldering with an incompletely heated solder, it lays down unevenly, in lumps, and has an ugly gray color. If the pad around the lead hole is not tinned or oiled, the solder will not lie flat. Therefore, before soldering, tin the contact pad, it should be covered with a thin, even layer of solder.
Step 4
Use a rosin-alcohol solution as a flux. To prepare the flux, take a small bottle of nail polish, it is very convenient with the presence of a brush. Crumble half of the rosin into it and fill it with ethyl alcohol. Wait for the rosin to dissolve. When working, gently apply the flux with a brush to the soldering area.
Step 5
Soldering field effect transistors requires special precautions. Such transistors are afraid of static electricity, you can ruin them by simply touching one of the terminals with your hand. The soldering iron must be grounded, disconnect it from the mains when soldering. Touch a grounded soldering iron before handling the transistor. Better yet, put a metal bracelet on your wrist that is connected to a ground - for example, a radiator.
Step 6
Before soldering, touch the contact pads of the board with a grounded soldering iron and only then insert the transistor. Take the transistor by the case. Wrap thin bare wire around the legs before soldering. As long as the legs of the transistor are connected together, static electricity does not threaten it. After soldering, gently unscrew the wire with tweezers and remove. Instead of a wire, you can use a piece of ordinary food foil: pierce it with the legs of the transistor, then, after soldering, remove. Make sure there is no piece of foil left between the leads.
