The book is devoted to modern methods of analyzing linear electrical circuits containing both active and passive elements and operating in steady and transient modes. The author widely uses the apparatus of wave matrices, which makes it possible to obtain original solutions. Active schemes are designed taking into account stability criteria. The book contains many practical examples illustrating the application of analysis methods. Serious attention is paid to the synthesis of filters, correction of the frequency characteristics of amplifiers and the use of feedback. Active schemes are considered. The book is a textbook for students of electrical and radio faculties.