PHYSICS CH5 Magnetism and Electromagnetism — Science STD 9 — Question

Transformer is a device used for converting low voltage into high voltage and high voltage into low voltage. It works on the principle of electromagnetic induction. It consists of primary and secondary coil insulated from each other. Depending upon the number of turns in the primary and secondary coils, the two types of transformers are; step-up or step-down transformers.

Step up and step down transformer.

1. Step up transformer:
   The transformer used to change a low alternative voltage to a high alternating voltage is called a step up transformer, ie (Vs > Vp) . In a step up transformer, the number of turns in the secondary coil is more than the number of turns in the primary coil (Ns > Np).
2. Step down transformer:
   The transformer used to change a high alternating voltage to a low alternating voltage is called a step down transformer (Vs < Vp). In a step down transformer, the number of turns in the secondary coils are less than the number of turns in the primary
   coil (Ns < Np).
   The formulae pertaining to the transformers are given in the following equations.

1. $\frac{\text { The number of primary turns } N_p}{\text { The number of secondary turns } N_s}=\frac{\text { The primary voltage } V_p}{\text { The secondary voltage } V_s}$
2. $\frac{\text { The number of secondary turns } N_s}{\text { The number of primary turns } N_p}-\frac{\text { The primary current } I_p}{\text { The secondary current } I_s}$