The aim of this application is to give you an introduction to the main principles of the electricity and electronics. It is not required to have any preexisting knowledge on the subject and it is therefore suitable for anybody wanting to make his first steps in the filed. A specially developed DC circuit simulator will give you the opportunity to explore in practice every chapter of the book and test your own ideas. Even though the DC circuit simulator is not a professional circuit design tool, it will give you the opportunity to explore many electronic circuits of your own design.