Business Ideas for Electrical Engineers

I'm confusing, which is the best & small scale industry

Sumanth, I'm an electrical engineer and I think I can help you with the basics. Don't think about starting a business based on 'Industry'. Because there will already be super heavy competition in it and existing businesses will make it difficult for a new business to make an entry.

You haven't told us how much investment you are willing to make and whether you've explored any ideas. You should also figure out whether you want to get into electrical related 'services' or wish to opt in for product manufacturing. 

There's another 'business' where in you could start coaching electrical engineering students and build up capital to start another products/services business. 

Tell us some more information about what you are thinking so that we can help you out.