Can I use the downloaded content form this site in my Engineering Thesis by giving the source ?
This is a tough one to answer really. Most schools will want you to design the project from scratch and on your own. Minus the hardware and other common components of course. I think so long as you don't use the whole design itself, can verify through contact with the engineer that made the design that it is credible and to industry standards, and of course site them and the source of information as the source, you should be okay. I would double check with your professors also just to be certain.