A free app for Android, by Therithal Info.

This is the best online study course for electrical and electronic engineering. It is free for all and contains many study topics and chapters.

It covers all major subjects including: circuit theory, digital logic circuits, electromagnetic theory, environmental science and engineering, electronics and electronic devices, linear integrated circuits and applications, electrical machines, power system analysis, power system operation and control, power electronics, control systems, measurements and instrumentation, industrial engineering, communication engineering, power plant engineering, power quality, electric energy generation, utilization and conservation, professional ethics in engineering, engineering mathematics, discrete time systems and signal processing, basic civil and mechanical engineering, environmental science and engineering, engine and drive, measurement instruments, electrical power and distribution, electric motors and electric motor theory, electric lines and electric wires, circuit boards and connectors, semiconductors, diodes, transistors, thyristor, transformer, harmonic resonant circuit, harmonic and vibrational spectra, wave optics, heat transfer, fluid mechanics, collision mechanics, thermodynamics, energy conversion, power plant engineering, power system operation and control, and many more.

This study course is very simple and easy to use. It is designed for all levels of learners and can be used by both professionals and nonprofessionals.