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Transformer.
A transformer is
made from two coils,
one on each side of a soft iron
core.
It can decrease the voltage
(called a step down transformer)
or increase the voltage
(called a step up transformer,
shown below).
Alternating current is passed through the
primary coil (the input)
which creates a changing magnetic field in the iron
core.
The changing magnetic field then induces
alternating current of the same frequency in the
secondary
coil (the output).
A step up transformer
has more turns of wire
on the secondary coil,
which makes a larger induced voltage in the
secondary coil.
It is called a step up transformer because the
voltage output
is larger than the voltage input.
If the secondary coil has
twice as many turns
of wire
then the output voltage will be twice the input
voltage.
(continued).
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