This textbook and exercise book for basic circuits in electronics, power electronics, and digital technology conveys the fundamentals of electronics at an intermediate mathematical level. It provides a concise introduction to electronics based on the current state of components and circuit techniques, and it presents all the basics of electronics in a structured manner within a single volume. The presentation of the teaching material is aligned with the level of technical schools and promotes understanding of electronic circuits and digitalization. The included review section on electrical engineering facilitates entry into the subject matter.