This is a great question. The wiring inside your home and devices is generally pure copper. It doesn’t matter if it’s microphones or phone chargers; it’s still copper. However, the insulation type and the thickness of the copper will affect the physical properties of cables.
What about other metals that can be used to conduct electricity?
GoldGold, although a poor conductor (and more costly), resists oxidation better than silver and copper. Therefore, connectors made of gold are often plated with it. If the surface becomes oxidized, they may become less durable.
Gold wire is also used in chips to bond the interconnects between the silicon and the chip package. Gold is used as it resists oxidation when bonding. Copper can also be used, but would need to be done in an inert atmosphere like nitrogen.
As you mentioned, silver has a higher conductivity than copper, but isn’t used widely due to its cost. But it does have a few niche uses where extremely low resistance is desired, such as in sensitive scientific instruments; cryogenics (where it’s desirable to have minimal heat generated in wires); and also in electrical contacts in switches, where the softness of silver and relatively good-conducting silver-oxide makes it a good choice for metal-to-metal connections
Aluminium conducts less well compared with copper – for a given size of cable copper will conduct better; but because aluminium actually has a better weight-to-conductivity ratio, aluminium wire with the same conductivity as copper wire would be physically thicker, but would still work out to be lighter, and probably cheaper too.
Aluminium is used in many overhead power lines because of its light weight and small physical dimensions.
Some aircraft wiring is made of aluminium to save weight; as are some motor windings where weight is important.
Sometimes, aluminum is also found in older domestic wiring that dates back to the 60s and 70s when copper was scarce. This led to an increase in copper prices.
Tungsten is used for wires that are resistant to heat, such as in incandescent lamps.
There are many different alloys used in electrical conductors. Here are some examples:
– Nickel-chrome (nichrome) wire, like tungsten, can survive high temperatures, and the higher resistance is desirable. Being cheaper than tungsten, is used in heater wires, where the wire doesn’t need to get white-hot.
– Solder, which is an alloy of tin and lead, or other mixes of metals in the case of lead-free solder, is used for bonding electrical components to copper pads on PCBs. The low melting temperature of tin-lead makes it suitable for this task.
– Cryogenic wire is often phosphor bronze (copper, tin, phosphorus), where the resistance of this alloy doesn’t change much at very low temperatures.