What is Transformer | Physics for EmSAT Achieve PDF Download

A fundamental transformer comprises two coils that are electrically isolated and possess inductance, yet are magnetically interconnected via a path of reluctance. The operational concept is elucidated through the provided diagram above for enhanced comprehension.

As depicted in the diagram above, an electrical transformer is composed of two coils referred to as the primary coil and secondary coil, wound around a soft iron core. The soft iron core is laminated to reduce the occurrence of eddy currents. Both coils within the transformer exhibit high mutual inductance.
The alternating flux generated in the laminated core induces a mutual electromotive force in the transformer, originating from the coil connected to an alternating voltage source. The majority of the alternating flux generated by this coil is coupled with the other coil, thereby generating the mutual induced electromotive force.

Induced EMF

The so produced electro-motive force can be explained with the help of Faraday’s laws of Electromagnetic Induction given:
By using the above equations we get :
e_s = N_sN_pe_p
The ratio N_s N_p is called transformation ratio. The transformer formula is given by:

Where, Vp = primary voltage, Vs = secondary voltage, Np = number of turns in the primary, Ns  = number of turns in the secondary.

Types of Transformers

There are two types of transformers:

• Step-up Transformer converts a low voltage into a high voltage. The number of turns in the primary coil is less than the number of turns in the secondary coil, i.e. Np < Ns.
• Step-down Transformer converts a high voltage when current decreases into a low voltage when current increases. The number of turns in the primary coil is greater than the number of turns in the secondary coil, i.e. Np > Ns. In short, a transformer carries the operations shown below:
  • Transfer of electric power from one circuit to another.
  • Transfer of electric power without any change in frequency.
  • Transfer with the principle of electromagnetic induction.
  • The two electrical circuits are linked by mutual induction.