What are Electrical Conductors and Insulators? | Definition, Types, Formula & Examples

What are Electrical Conductors and Insulators?

Some materials allow electric current to flow more freely than others. These materials are called conductors. Other materials resist the passage of electric current. These materials are called insulators. Both conductors and insulators are important in the field of electronics.

Electrical Conductors

Electrical conductors allow electricity to flow easily due to their atomic composition. In a conductor, the outer electrons of the atom are loosely bound and can move freely through the material in the presence of an electric charge.

Conductive Materials

In general, the best conductor of electricity is metal. Metals tend to have electrons in the outer shells of atoms that are shared freely. The best conductor of all the elements is silver. Unfortunately, silver is too scarce and too expensive to use in most electrical appliances. The most common electrical conductor today is copper. Copper is used in electrical wiring and circuits around the world.

Conductance and Resistance

Another way to think of conductivity is the opposite of resistance. The resistance of a material is a measure of a material’s ability to resist electric current. Sometimes conductivity is indicated by the letter “G” where G is the reciprocal of resistance, R.

G = 1/R

Using Ohm’s law we know that resistance is equal to voltage divided by current or R = V/I, So

G = I/V

Superconductors

Superconductors are materials that conduct electricity completely. It has zero resistance. All superconductors discovered so far by scientists require very cold temperatures of minus 234 degrees Celsius to become superconductors.

Electrical Insulators

The opposite of a conductor is an insulator. An insulator that resists the passage of electric current. Insulators are important to protect us from electricity. The power cord to your computer or TV is covered with insulating rubber to protect you from electric shock. Good insulators include glass, air and paper.

Semiconductors

Some materials act between conductors and insulators. These materials are called semiconductors. Semiconductors are important in electronic devices such as computers and cell phones because their conductivity can be controlled, allowing current to flow in only one direction or only in certain cases. The most common semiconductor used in electronics today is silicon.

Interesting Facts about Electrical Conductors and Insulators

Most good conductors of electricity are also good conductors of heat.

Temperature can play an important role in the electrical conductivity of a material. In general, the higher the temperature, the lower the conductivity because the resistance increases with temperature.

Aluminum has a lower electrical conductivity than copper, but is sometimes used in lower-cost wiring.

Many electronics companies have their headquarters in California’s “Silicon Valley,” nicknamed after silicon semiconductors.