This paper presents the results of the experimental research on the electrical characteristics of two dissimilar thermoelectric power sources. Chromel-alumel and nichrome-constantan are the investigated types of thermocouples that are utilized as thermopower sources. Through the assistance of the collected data, experimental and theoretical studies of two equivalent thermopower sources are done. The first studied source is obtained by a parallel connection of the two types of thermocouples, and the second studied source is achieved by the parallel connection of two thermocouples of nichrome-constantan and a single thermocouple made of chromel-alumel. Theoretical studies of the two equivalent thermoelectric sources proved good repeatable precision of the studied results of experimental measurements.