Electric brake booster for controlling the master cylinder of a brake circuit

The booster (100) has an assistance piston (6) provided with a lever (5), where a support point (51) of the lever is articulated to a back part of the assistance piston and supported against a plunger piston (8) by an intermediate point (52) of the lever. An end (53) of the lever rests against a rear limit (13) that is formed by a housing (1) of the booster and defines a rest position of the booster. A return spring (41) pushes back the assistance piston that carries the support point. A cut spring (9) is compressed by the plunger piston that is supported against the intermediate point.