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 it works. Give its tow uses.

Answer 1

The device is step down transformer.

Working: In a stepdown transformer, the number of turns in secondary coil are less than the number of turns in the primary coil i.e., turns ratio n<1 or NS/NP<1.
As `"E"_"s"/"E"_"p" = "N"_"S"/"N"_"P"`.

So `"E"_"s"/"E"_"p"` < 1 which means Es is less than Ep.
Two uses of step down transformer are:

1. With electric bells.
2. At the power sub-stations to step-down the voltage before its distribution to the customers.