The book outlines the basics of modern electronics. Information is given on the device and principles of operation of the main types of semiconductor and electric vacuum devices, methods of their application in circuits, methods of analysis, calculation and design of electronic circuits. The main focus is on semiconductor devices and circuits on them. The book is offered as a textbook for students of the specialty of mathematical and calculating-decisive instruments; and devices. It can be useful for students of other specialties, as well as engineers, graduate students and researchers working on the creation of electronic circuits.