Hi....My prof. asked me to design adapter with: active rectifier (as input to the adapter) which draws a unity power factor current. Then use a high frequency transformer to isolate and generate a 12V DC.
I am not sure how to start this project. Ill be thankfut if anyone can provide me with help. thanks

 

I guess if your professor asks you to do that, you should have sufficient knowledge to be able to.
Write your ideas about how do you think the circuit will look like, so we can start from somewhere.