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Basics of Electricity
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What is Electricity?
The fundamental building block of all matter is the atom. An atom has a nucleus at its
centre surrounded by one or more orbiting, electrons. See
Figure 1.1.
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Figure 1.1. Typical atom.
Atoms are very small. A cubic centimetre of matter contains millions of atoms. See
Figure 1.2.
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Figure 1.2. Millions of atoms per cc.
Copper wire is made up of millions of atoms. Without going into all the details of
how it happens, some electrons orbiting the nuclei of copper atoms can be made to move from the
orbit of one atom to the orbit of the next atom in an orderly fashion. As shown in
Figure 1.3, electron 1 of atom A moves to atom B. Electron 2 of atom B moves to
atom C, and so on.
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Figure 1.3. Electrons can move from one atom to another.
Electricity is produced when electrons are moved in the same direction in an
orderly manner through a conductor, such as copper wire. Causing electrons to move from one atom to
another in a copper wire is relatively easy because copper wire is a good conductor of electricity.
Other good conductors are aluminium and silver.
Materials such as glass and plastics are not good electrical conductors. Poor
electrical conductors are called insulators.
Electric Current Flow
The flow of electricity through a conductor can be compared to the flow of water through a
pipe. See
Figure 1.4.
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