A circuit for processing an analog signal having a time sequence of discrete signal levels, each of which lies in a time interval and represents an information-bearing segment of the interval while the rest of the time interval is a non-information-bearing segment, comprises a transistor in emitter-follower or source-follower configuration, a high emitter or source resistance or, instead, a high-ohm constant current source, and a device for applying a voltage supply, as well as a switch which is connected between the emitter and a reference potential to prevent a current from flowing via the high-ohm resistance or the high-ohm voltage source for charge reversal of an output capacitance of the circuit in one direction, whereas for charge reversal in the other direction the dynamic current boosting effect of the transistor is exploited. This results in a fast emitter-follower or source-follower circuit which is particularly suitable as the output stage for image sensors.