Transformers

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Transformers
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• Electric Generators- the main function of an
  electric generator is to convert mechanical
  energy to electrical energy.
• Electric motors- main function of an electric
  motor is to convert electrical energy into
  mechanical energy.

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Transformer

• A device that increases or decreases the emf of
  alternating current.
• Reminder emf is the energy per unit charge
  supplied by a source of electric current.

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AC Transformer

• consists of two coils of wire wound around a
  core of soft iron.
• The coil on the right has N1 turns and is
  connected to an input ac potential difference
  source. This is called the primary winding.

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• The coil on the left is connected to a resistor R
  and consists of N2 turns, is the secondary.
• The difference between the two is the amount of
  turns N

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Transformer equation

• ?V2N2 ?V1

N1
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Step-up

• When N2 is greater than N1 the secondary emf is
  greater than the primary making it a step up
  transformers.

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Step Down

• When N1 is greater than N2 the secondary emf is
  less than that of the primary making it a
  step-down transformers. Examples