Electric circuits are made up of components connected using conductors. Conductors allow the flow of electric current between the components of a circuit. When we want to prevent current from flowing, we use insulators. As the name suggests, semiconductors fall somewhere between conductors and insulators in that they are capable of conducting current, but the level of conductivity can be altered.
In this tutorial:
Resistance
We can compare the ability of different materials to conduct current by measuring their resistance. A good conductor offers little resistance, and a bad conductor offers a lot of resistance. If the material does not conduct a current at all, it is an insulator.
Aside from the material of the conductor, the following affect resistance as well:
- Temperature: resistance causes an increase in temperature, and an increase in temperature results in an increase in resistance.
- Cross-section: the thickness of a conductor
- The length of the conductor
See the All about Resistors tutorial as well.
Conductor
“A conductor is an object or type of material that allows the flow of charge (electric current) in one or more directions.” [1]
Insulator
When we need to prevent current flow, we use an insulating material that does not conduct electricity.
Materials
Metals
Metals are good conductors: silver, copper and aluminium. Silver is the best conductor, but because it is expensive, cheaper copper is commonly used.
Do not confuse silicon with silicone!
Non-metals
Non-metallic substances such as silicon and graphite are conductors.
Silicon is the material used in many modern electrical devices such as transistors, solar cells, and integrated circuits. [2] The late 20th century to early 21st century has been described as the Silicon Age because of the large impact that silicon has had on modern technology. Just think of the name of the area where many of the world’s tech giants are based: Silicon Valley!
Graphite is a crystalline form of Carbon. [3] It is mixed with clay to make the “lead” in your pencil.
Liquids
Some liquids can conduct water. Although pure water is non-conductive, adding salt allows current to flow.
Gases
Under the correct circumstances, even some gases can conduct electricity. Neon tubes are an example of plasma (ionised gas) conducting electricity to provide lighting. [4]
References:
- Wikipedia. Wikimedia Foundation. (2024) Electrical conductor. Available at: https://en.wikipedia.org/wiki/Electrical_conductor (Accessed: 26 February 2025).
- Wikipedia. Wikimedia Foundation. (2025) Silicon. Available at: https://en.wikipedia.org/wiki/Silicon (Accessed: 26 February 2025).
- Wikipedia. Wikimedia Foundation (2025) Graphite. Available at: https://en.wikipedia.org/wiki/Graphite (Accessed: 6 March 2025).
- Wikipedia. Wikimedia Foundation. (2025) Plasma (physics). Available at: https://en.wikipedia.org/wiki/Plasma_(physics) (Accessed: 26 February 2025).