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© Boardworks Ltd 2012
Parts of a transformer
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© Boardworks Ltd 2012
Using a transformer to change voltage
The voltage induced in the secondary (output) coil depends
on the number of turns on the primary and secondary coils.
A step-up transformer
has more turns on the
secondary coil and so
increases voltage.
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A step-down transformer
has fewer turns on the
secondary coil and so
decreases voltage.
© Boardworks Ltd 2012
Investigating transformers
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© Boardworks Ltd 2012
Properties of transformers
Transformers transfer power between circuits. The design of a
transformer determines the characteristics of the electricity
flowing in its secondary circuit.
The frequency of the alternating current in the secondary
circuit matches the primary circuit, but what about voltage?
The voltage in each circuit is related to the number of coils
on each side of a transformer by the following formula:
primary voltage
secondary voltage
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primary turns
secondary turns
© Boardworks Ltd 2012
Calculating voltage
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© Boardworks Ltd 2012

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