A free app for Android, by LeopardDevelopers.
This app provides a basic knowledge of electronics. It will cover topics such as the definition of electronics, the difference between AC and DC, voltage, current, and resistance, ohms law, the diode, the JFET, MOSFET, and the PN junction, and many more.
You can also learn about solar power, how it works, and what you need to do in order to generate it. You will also be able to find out what a transformer does and how it works.
This app will help you understand the concept of energy and how it is used to provide electricity to our homes.