I have a hair dryer which is of japan it needs 120volt where as i have a 220volt switch board in india its 220volt current supply so can anybody help me to built a transformer of step down converter

 

Are you sure there isn't a voltage selector switch somewhere on the hair dryer? If it's a hand held type they often come with that option built in.
Otherwise it's probably just as cost effective to buy a hair dryer compatible with your current 220V supply voltage.

 

I don't think this qualifies as a physics problem, so I have moved the thread here.

 

"Travel" step down plug-in transformers to perform that function are very common.

 

"Travel" step down plug-in transformers to perform that function are very common.

Lets see...
step down transformer for a hair dryer.. $40 USD???
New hair dryer=maybe $20 USD??
Solution is simple..

 

I actually needed to built a step down transformer. That's if the voltage is 220 volt i needed it to 110volt if its 110volt i need to 2volts. That 220volt to 2volt range i only need a some circuit diagrams to built it and few steps and some info and the list of components needed to setup a step down converter/transformer. In india we have 220 voltage supply so i need not need a step up converter/transformer. I only need is only a step down converter/transformer. Can some help me in making this device(step down converter/transformer)

 

No you don't.. you need to buy a new hair dryer.

2 volt???