The textbook discusses the physical principles of operation and structures of electronic devices; formation and properties of the p-n junction, contact phenomena therein; device, operating principle, basic parameters, parametric ratios, and switching circuits of semiconductor and photoelectronic devices - diodes, thyristors, bipolar and field-effect transistors with p-n junction and with insulated gates, photoresistors, photo- and light-emitting diodes, phototransistors and photomultipliers.