The paper describes the features of an automated system for measurement and processing of electrical characteristics of BJTs and MOS transistors in the presence of thermal and radiation effects. Automation is made possible with employing of long measurement cables and a ramified scripting system. The system is based on a set of measuring instruments, methods of measurements and processing of results for transistors of various types. Shown are the examples of the system usage for studying BJTs and MOSFETs, determining the SPICE-model parameters.