Electrical conduction is the movement of electrically charged particles due to a force exerted on them by an electric field. The electric current formed by this movement travels through a medium called a conductor.
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Conductors Conductors are materials that allow an electric current to pass with low resistance. Resistance is the electrical equivalent of friction, as it causes energy loss and the production of heat. Different materials provide varying degrees of conductivity. Some examples of good conductors are silver, copper, and steel. Current flow in metal conductors is a result of the movement of electrons. Current flow in electrolytes – electrically conductive fluids – is a result of the movement of electrically charged atoms, or ions. |
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Semiconductors A semiconductor is neither a good conductor nor a good insulator, but somewhere in between. The conductive capability of a semiconductor can be permanently changed by introducing impurities through a process known as 'doping', or it can be temporarily modified by the application of an electric field. The ability to very precisely and dynamically vary their conductivity makes semiconductors very important materials in electronic devices such as computers and cell phones. Silicon is the most common and most commercially important semiconductor material. |
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Insulators Materials that do not support the passage of an electric current through them are known as insulators. Plastics and rubber are examples of good insulators. Because it contains no substance of any kind which could transport a current, a perfect vacuum would also be a perfect insulator. |
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Superconductors
Superconductors are conductors that can be made to conduct electricity without any resistance at all, so they do not lose energy or generate heat. All conductors in general use have some resistance even though that resistance may be very low. Superconductivity in materials has only been achieved at extremely cold temperatures, so it does not yet have any common practical applications.
