Method and apparatus for feeding a measuring electronics

A method for feeding a measuring electronics (3) in a through which a fluid fitting (2) with electric energy, which the armature (2) is generated by flowing fluid in a turbine (7), wherein the flow rates and pressures vary, characterized in that that the pressure drop through the entire apparatus combination is measured and the turbine (7) a pressure control device (5) is associated, which controls the pressure of the turbine (7) impinging the fluid in dependence of the detected pressure loss that for the operation of the measurement electronics (3) required electrical energy is generated, wherein the pressure loss is limited to a maximum value.