It is difficult to imagine the life of a modern person without the widespread use of electronic equipment. Radios and televisions, tape recorders and VCRs, electric players and CD laser players surround each person. Methods of radioelectronics and radioelectronic equipment are widely used in scientific research, in production and in school practice. Without knowledge of the basics of radio electronics, it is impossible to understand the principles of work and the device of school electronic equipment, conduct extracurricular work on radio electronics at school, and engage in amateur radio.