Copper is usually used to conduct electricity in wires and cables. However the contacts in certain switches and in computer equipment use gold. Explain this.Thanks!
Because gold conducts electricity, does not tarnish, is very easy to work, can be drawn into wire, can be hammered into thin sheets, alloys with many other metals, can be melted and cast into highly detailed shapes, has a wonderful color and a brilliant luster.
Copper is an excellent conductor, however, with time and heat it will tend to form copper oxide, which is non-conducting. In some switches, just turning them on and off will tend to wipe off this layer as it forms, but this is not always the case. So in certain more critical applications, the contact surfaces will be coated with gold because it does not form an oxide layer and protects the contact surfaces in relays and switches.