About the book: 2015 / You can brighten up your leisure time in different ways. Do-it-yourself electronic devices, powered by a “safe” voltage of 9-15 Volts, not only successfully replace Chinese “gadgets”, but also allow you to cultivate your own creative streak, transforming free leisure time into a very useful developmental activity. Here is a well-structured book, divided into three thematic chapters of the “freshest” amateur radio experience, which allows you to unconventionally solve the problems that we face every day in everyday life. The special, distinctive purpose of the book is to describe proven, practical, easily repeatable circuits and devices; Each chapter has a special section - a description of options for the practical application of the developments proposed for repetition. A book for radio lovers of all ages, people of any profession, inclined to engage in technical creativity and a wide range of readers who value their leisure time and new promising ideas for filling it. This book is for you.