The technique of characteristics of thermoelectric energy converters based on the study of the frequency dependence of their impedance is presented. Specialized hardware and software for impedance spectroscopy of thermoelectric modules have been developed. For the analysis of the obtained spectra, an electrothermal model was taken as a basis, which describes the experimental results well and allows one to obtain not only electrical but also thermal characteristics of a thermoelectric energy converter.
 B. Beltrán-Pitarch, J. Prado-Gonjal, A. Powell, “Experimental conditions required for accurate measurements of electrical resistivity, thermal conductivity, and dimensionless figure of merit (ZT) using Harman and impedance spectroscopy methods”, Journal of Applied Physics, vol.125, no.2, p. 025111, 2019.
 C. Vineis, A. Shakouri, A. Majumdar, M. Kanatzidis, “Nanostructured Thermoelectrics: Big Efficiency Gains from Small Features”, Adv. Mater., no.22, p.3970, 2010.
 B. Stadnyk, P. Skoropad, S. Yatsyshyn, “Thermometry: from sensitive material to thermoelectric thermotransducer”, Measuring equipment and metrology, vol.81, no.3, pp.28-32, 2020.
 R. Dunets, B. Dzundza, M. Deichakivskyi, V. Mandzyuk, A. Terletsky, O. Poplavskyi, “Methods of computer tools development for measuring and analysis of electrical properties of semiconductor films”, Eastern-European Journal of Enterprise Technologies. vol.1/9, no.103, pp.32-38, 2020.
 J. Martin, T. Tritt, C. Uher, “High temperature Seebeck coefficient metrology”, Journal of Applied Physics, no.108, p.121101, 2010.
 J. De Boor, E. Müller, “Data analysis for Seebeck coefficient measurements”, Review of scientific instruments, no.84, p.065102, 2013.
 A. Kumar, A. Patel, S. Singh, K. Asokan, D. Kanjilal, “Apparatus for Seebeck coefficient measurement of wire, thin film and bulk materials in the wide temperature range (80 – 650 K)”, The Review of scientific instruments, no.90, p.104901, 2019.
 Y. Tur, Y. Pavlovskyi, І. Virt, “Measurement of thermoelectric parameters of thin-film semiconductor materials using the Harman method”, Physics and Chemistry of Solid State, vol.20, no.3, pp.306–310, 2019.
 D. Adam, P. Downey, P. Timothy Hogan “Characterization of thermoelectric elements and devices by impedance spectroscopy”, Review of Scientific Instruments, no. 78, p.093904–1–12, 2007.
 J. Garcıa-Canadas, Gao Min, “Impedance spectroscopy models for the complete characterization of thermoelectric materials”, Journal of Applied Physics, vol.116, p.174510–1–7, 2014.
 D. Bobyljov, “Optimization of the measurement process in virtual impedance analyzers by combining sinusoidal and polyharmonic test signals”, Measurement. Monitoring. Management. Control, no.2, pp.86–91, 2012.
 S. Obraztsov, Y. Troitskiy, “ AD5933 precision impedance converter”, Modern electronics, no.9, pp.12–15, 2009.
 V. Dumbrava, L. Svilainis, “The Automated Complex Impedance Measurement System”, Electronics and Electrical Engineering, vol.4, no.76, pp.59–62, 2007.