Transformers | Physics for GCSE/IGCSE - Year 11 PDF Download

Transformer

• A transformer is a device utilized to modify the value of an alternating potential difference or current.
• This alteration is accomplished through the generator effect.

Structure of a Transformer

• A basic transformer comprises:
  • A primary coil
  • A secondary coil
  • A soft iron core
• Iron is utilized due to its easy magnetization.

Operation of a Transformer

Primary Coil Operation

• An alternating current is fed into the primary coil, causing a fluctuating magnetic field.
• This varying magnetic field passes through the iron core, inducing a changing magnetic field in the secondary coil.

Secondary Coil Operation

• The induced changing magnetic field in the secondary coil creates a potential difference.
• This potential difference allows for the transfer of electrical energy from the primary coil to the secondary coil.

Electromagnetic Induction

• This field changes and penetrates the secondary coil, generating a potential difference.
• When the magnetic field changes continuously, an alternating potential difference is induced. This induced potential difference matches the frequency of the alternating current supplied to the primary coil.
• If the secondary coil forms a complete circuit, it initiates the flow of an alternating current.

Step-up & Step-down Transformers

• A transformer comprises a primary and secondary coil.
  • The primary coil represents the initial coil, while the secondary coil denotes the subsequent coil.
• A step-up transformer raises the voltage of a power supply.
  • This type of transformer possesses a higher number of turns on the secondary coil compared to the primary coil (N_s > N_p).
• Conversely, a step-down transformer reduces the voltage of a power supply.
  • Such transformers have a lower number of turns on the secondary coil than on the primary coil (N_s < N_p).