Instruments RD-20, RD-21 and RD-23 (further RD-2X) are the single-phase model (standard) counters of electric power with the high accuracy of the measurement of current, voltage, active and reactive energy and power. A series RD personified before itself the new technology of the measurements Of dytronics, based beyond the use of the integrating analog-to-digital converter (converter) of signal. In contrast to already existing ATsP, utilized before other instruments, ATsP Dytronic is specially developed for measuring the parameters of electric power. This makes possible AT THE POINT OF RD-2X to conduct measurements with the exceptional accuracy even due to the conditions of interferences.