What type of transformer is used in a 6V bed lamp ?

What is the use of transformer

What is the use of transformer?

The number of turns in the primary coil of a transformer are 100 and that in the secondary coil are 200. What type of transformer is it ? If the input voltage in the primary coil of the transformer is 200 V, find the output voltage in the secondary coil of the transformer.

A step down transformer has 800 turns in the primary. The supply voltage is 240 V. If the transformer is to be used to light a 6V lamp, what should be the number of turns in the secondary?