Tranformers

• STEP-UP transformers increase the voltage.

  STEP-DOWN transformers decrease the voltage.
• • Both transformers consist of two coils of wire wrapped around an iron core.
• Diagram of transformers

  
• Magnetic field is used in transformers to step up and step down voltage.

  There are three steps.
• 1. The alternating current flowing in the primary coil creates an alternating magnetic field (around primary coil).
• 2. The soft iron core strengthens the field and connects it to the secondary coil - no current flows through the iron core.
• 3. The alternating magnetic field induces a voltage in the secondary coil , causing an alternating current to flow in the secondary coil.
• • If input current didn’t alternate, there would be no induced current.
• LAMINATED SOFT IRON CORE is used…

  • to strengthen magnetic field.
  • as a magnetic link.
• During use, the iron core heats up - to reduce energy losses, a laminated (layered) iron core is used (less vibrations) - this makes the transformer more efficient.