Abstract: Method and device by which, at a given instant, a conductor (4) at the output of a capacitor (5) carrying a video signal is connected to a reference voltage source (1, 2). The use of a voltage source (1, 2) whose impedance depends on the direction of the current which it supplies, makes it possible to connect the conductor (4) to the voltage source (1, 2) during the whole duration of a line flyback, instead of being obliged to use a special pulse occurring solely at the end of the line flyback time. In the case of positive white, for example, a positive current supply part of the voltage source (2) having a high impedance sends a positive supply current to the conductor (4) carrying the video signal, and a low-impedance negative current supply part (1) connects this conductor to ground.