At present, simulators-analyzers of amplifiers and microwave generators have found wide application in computer-aided design systems. Simulators-analyzers allow to simulate these devices in accordance with the technical design for their design and measure the parameters of its loads in the real operating conditions of this device in the amplifying and autogenerating modes. Such an adequate measurement of the parameters of the transistor and the parameters of its loads for the design of amplifiers and self-excited generators makes it possible to increase the economic efficiency of the computer-aided design systems of these devices, since it eliminates the need for multiple correction of their prototype. The proposed article is devoted to the solution of the problem of providing an automated specification of complex reflection coefficients of loads of a transistor with the help of tunable matching transformers of the simulator-analyzer in the simulator simulation of amplifiers and selfexcited generators. After measurement, complex reflection coefficients are used for direct calculation and design of these devices, without using the parameters of the transistor. To solve the automation problem, a mathematical model of a tunable matching transformer and a mathematical model of its calibration nave been developed that provide the possibility of automatically specifying the required parameters for reflecting the loads of the transistor in simulation of an amplifier and an autogenerator based on a preliminary approximate calculation of these parameters by the computer aided design system.