About the book: 1969 / The author tells amateur radio inventors how they can sometimes unexpectedly use a sound generator in the design of many devices and devices used in everyday life, the national economy, sports, medicine, when studying problems of engineering psychology. Individual devices can be used in medical and biological groups for research work. Based on the presentation of the material, the book is accessible to beginning radio amateurs, it can serve as a manual for radio engineering circles, but the designs that are described in it will also be of interest to many trained radio amateurs.