Solder is essential for creating strong, conductive connections between components on a PCB. Solder wire comes in both leaded and lead-free options, with leaded solder offering ease of use and low melting points, while lead-free solder is used for modern, eco-friendly applications. Low-melt solder is ideal for rework and delicate electronics where heat-sensitive components require minimal thermal stress. Each type ensures durable and reliable connections in electronics repair and assembly.