The most common alloys used for electronic repair are _____ and _____.

• A. Copper and Tin
• B. Lead and Silver
• C. Gold and Tin
• D. Tin and Lead

Answer: (D)

Solder is an alloy chosen for its melting point, flow, and how well it wets metal surfaces. The traditional and most common combination used for electronic repair is tin with lead, i.e., tin-lead solder. This pairing melts at a relatively low temperature, flows smoothly to coat joints, and forms strong, ductile connections with copper and tin-coated leads. In particular, the common eutectic ratio (tin-lead) melts at a single sharp temperature, giving clean, quick transitions and reliable joints. Lead helps lower the melting point and improves wetting, while tin provides good solderability and corrosion resistance, keeping costs down and joints durable. While lead-free solders are widely used today for environmental reasons, tin-lead solder remains the standard choice for many repair tasks due to its proven reliability and ease of use.