Due to their advantageous properties, universal motors are widely used in various applications and can be operated with both AC and DC voltage. Between main advantages of universal motors are their high starting torque, very compact design and high operating speed. In terms of the wide use of the universal motor, we want to analyze the impact of DC and AC power supply on the universal motor in this article. As part of the analysis, measurements were made of the influence of the AC/DC supply on the speed, torque, efficiency and electromagnetic radiation of the motor. At the end of the paper, the results of measurements on a universal motor with DC and AC power supply are presented.