An electronic or electromechanical system including at least one electrical energy source, a first circuit capable of operating in at least two operating modes, one of which corresponds to the stopping of the application circuit, and a circuit for transmitting the electrical energy from the energy source to the application circuit, the transmission circuit being further capable of determining a first value of the maximum instantaneous electric power capable of being supplied by the energy source, of determining a second value of the instantaneous electric power consumed by the application circuit in at least one of the operating modes, and of storing the first and second values or of selecting the operating mode of the application circuit from among said at least two operating modes based on the first and second values.