A soldering iron is a hand-held tool used to join two or more electronic components together by melting solder, a metal alloy. It typically consists of a metal tip that heats up when electricity flows through it, allowing the user to apply heat directly to the parts being joined. Soldering irons come in various wattages, with higher wattages providing more heat for larger components. The process of soldering is essential in electronics, as it creates strong electrical connections. Proper soldering techniques ensure reliable performance in devices like circuit boards, where components such as resistors, capacitors, and microchips are connected.