The paper deals with the electrophysical principles of the method of electrogas- and electro-hydrodynamic conversion of electric signals to pneumatic (hydraulic) signals and vice versa using corona discharge for the control of gas and liquid volumes, flows and jets of working media in electropneumohydraulic systems, including problems of formulating requirements for the working media and electric circuits of converters, estimating the limiting ranges of pressure, velocity, and temperatures of the working media and limiting dynamic possibilities, and determining conditions for production of potential signals, stable control, and extension of the control ranges.