The practical guide presents the basics of electricity and the development of electronic devices. It discusses the application of basic components, semiconductors, optoelectronic elements, and sensors. It describes the development and practical application of operational amplifiers, filters, oscillators, timers, voltage regulators, and power supplies. It demonstrates the use of logic chips, liquid crystal, and LED displays. Microcontrollers and platforms for developing device prototypes, including the Arduino board, are also covered. The connection of DC motors, servos, and stepper motors, as well as microphones, audio amplifiers, and speakers, is described. The material is accompanied by detailed and clear instructions, circuit diagrams, and illustrations. The fourth edition of the book includes completely new chapters on sensors, microcontrollers, modular electronics, and the latest versions of software tools.