Question

Draw a labelled diagram of a device you would use to transform 200 V a.c. to 15 V a.c. Name the device and explain how does it work. Give its two uses.

Answer 1

The device is a step-down transformer.

Working: In a step-down transformer, the number of turns in the secondary coil is less than the number of turns in the primary coil i.e., turns ratio n<1 or NS/NP<1. As Es/Ep = Ns/Np.
So Es/Ep<1 which means Es is less than Ep.

Two uses of a step-down transformer are:

(i)With electric bells

(ii)At the power sub-stations to step-down the voltage before its distribution to the customers