Conductors
Most of the conductors used in electronics are metals like copper,
aluminium and steel. Conductors are materials that
obey Ohm's law and have very low resistance. They can therefore carry
electric currents from place to place without dissipating
a lot of power. As a result, metals are useful as connecting wires to
carry electrical signals from place to place. They help ensure
that most of the signal's power reaches it's destination instead of
warming up the wires in between!
In fact, although it sounds odd, modern resistors are also made of conductor materials. However, they use very thin pieces
of conductor which don't pass current too easily.
eg:- Copper
Semiconductors
All the transistors, diodes, integrated circuits, etc. used in modern
electronics are built using a range of semiconductors. The basic
property of a semiconductor is given away by its name - it 'conducts a
little bit'. A semiconductor will carry electric current, but not as
easily as a normal conductor.
Some materials are intrinsic semiconductors. The semiconducting properties occur in these materials naturally. However,
most of the semiconducting materials used in electronics are extrinsic. This means that left to themselves they are excellent
insulators. These materials are turned into semiconductors by doping them with small amounts of foreign
atoms. The number
of doping atoms you need to add is very small. If you left all the
doping atoms inside the package of a transistor and removed the bulk of
the material you'd be left with a vacuum better than exists between the
planets of the solar system!
eg:- Silicon and Germanium
Insulators
Glass, most polymers (plastics), rubber and wood are all examples of
insulators. These are materials which will refuse to
carry an electric current. They are useful for jobs like coating
electric wires to prevent them from 'shorting together' or giving you
a shock. Silk and cotton are also good insulators (when they're dry!!)
and some of the mains wiring in very old houses once used
them - but by modern standards this was pretty dangerous since you could
get a shock when wet or a spark would set them alight when dry!
Modern insulators like PVC (PolyVinylChloride) are much better and safer.
Insulators are also very useful to fill the 'gap' in between the metal
plates of a capacitor. Very old capacitors (and some modern
radio ones) use air gaps since air is a good insulator.
eg:- Rubber,PVC(PolyVinylChloride)
Conductors Insulators Semiconductors Video
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