Phosphor bronze

Phosphor bronze is a bronze, an alloy of copper and tin, with a trace of phosphorus. It is strong, springy and resists wear and corrosion, yet still conducts electricity well enough for electrical contacts.

It is made by melting copper and stirring in tin, from about 1 to 10 percent depending on the grade. A small amount of phosphorus, usually added as a copper-phosphorus alloy, grabs oxygen dissolved in the melt and carries it off, so the metal casts clean and free of bubbles. A trace of phosphorus stays behind. The alloy is cast, then rolled into thin strip or drawn into wire. Rolling it cold is what gives it its spring: the more it is worked, the harder and springier it becomes.

In a TV it forms the contacts inside every connector. A contact must press against its partner with steady force for years and survive being plugged in many times, which is exactly what phosphor bronze is good at. The same alloy makes springs, bearings and the strings of many acoustic guitars.