Download Electrical principles - Totton College

ELECTRICAL
PRINCIPLES
WHAT IS
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ELECTRICITY
Electricity. It's everywhere. It's in your house, in the air, in your body!
A current of electricity is a steady flow of electrons. When electrons move from
one place to another, round a circuit, they carry electrical energy from place to
place like marching ants carrying leaves.
Instead of carrying leaves, electrons carry a tiny amount of electric charge. The
charged particle can be either positive or negative.
In order for a charge to flow, it needs a push (a force) and it is supplied by
voltage, or potential difference. The charge flows from high potential energy to low
potential energy.
Current will only flow is there is a complete circuit between a source of high
voltage and low voltage (electrical pressure). It is this electrical pressure or voltage
that pushes the electrons and causes the movement.
A circuit is a closed path or loop around which an electric current flows
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Resistance means how much something opposes current flow
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Electricity appears in two forms: alternating current(AC) and direct current(DC).
DIRECT
CURRENT
Direct current does not change directions
 The electron flow is always from the negative pole
to the positive pole
 Direct current is almost always what is used inside
of electronic devices to power the various internal
components.
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ALTERNATING
CURRENT
Alternating current does change direction ~the
direction of current flowing in a circuit is constantly
being reversed back and forth
 Flexibility in traveling long distances.
 Used for audio signals
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