A soldering iron is a tool designed for joining metal materials, most commonly in electronics, using molten metal called solder. Its principle of operation is to electrically heat a small metal tip at the end of the tool to a temperature sufficient to melt the solder wire, often referred to as "tin". This molten metal is applied to the points to be joined, such as the pins of the component and the contact area on the circuit board. Once cooled, the solder solidifies to form a strong and electrically conductive connection. The key component is the aforementioned soldering tip, which is usually replaceable. There are different tip shapes and sizes for different types of work - from very thin and pointed for small parts to flat or bevelled for larger joints. This variability allows precise heat targeting only where it is needed. Many models are equipped with a temperature control that allows you to set the optimum heat for the specific solder type and sensitivity of the components being joined, preventing damage from overheating. The tool is thus used when fitting electronic boards, repairing consumer electronics or connecting wires.