A deflection system for driving an electron beam in a raster scan including a deflection coil L1 energised by a linear amplifier A1 effective to produce an output current proportional to the input voltage signal during the forward scan of the raster. A resonant switch circuit 11 causes resonant flyback of the current through the deflection coil L1 at the end of each line of the raster scan. A current boost circuit 51 including a constant current source 53 is provided to provide current to the resonant switch means during the flyback period to restore the current through the deflection coil L1 to its initial scan value.