Question

Describe with the help of a clear diagram the structure of a.c. transformer, suitable for lighting 12V lamp from 240V mains.

Answer 1

We are to transformer for lighting 12V lamp from 240V mains. Therefore step down transformer is needed. The magnitude of induced e.m.f. is produced by the formula

Primary coil: 

• It should have 20 times more number of turns as compared to secondary coil. 
• It is made of thinner copper wire. 
• It should be more heavily insulated secondary coil. 

Secondary coil : 

• It should be made of thicker copper wire. 
• It should be less heavily in solated.