Systematized information on the use of various kinds of digital integrated circuits in microprocessor technology and microcomputers. Circuitry, purpose, methods of use and design features of digital microelectronic devices are described. Options for layout and printing installation were considered, diagnostics of digital equipment malfunctions was discussed. Domestic analogues are given for the microcircuits in question. For a wide range of readers who do not have special training in the field of electronics and digital microprocessor technology.