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Transformers

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Parts of a transformer

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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

.

3 of 6 A

step-down transformer

has fewer turns on the secondary coil and so

decreases voltage

.

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Investigating transformers

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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 = primary turns secondary turns

V

p

V

s =

N

p

N

s

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Calculating voltage

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