This thesis discusses, evaluates and, where possible, demonstrates the opening and closing stages of switching techniques and circuit arrangements needed to condition (sharpen) the output current pulse of a helical flux compression generator. The sharp rise in resistance that accompanies the rapid fusing of a thin metal foil (termed a fuse) opens the circuit in the initial stages, and a fast-acting plasma erosion switch (PEOS) whose output circuit is magnetically insulated at the end of its opening phase provides the same duty in the final stage. The study is directed towards a generator having a 1-to-2 MJ and multi-MA rating accumulated in about 150 microseconds, the ultimate aim being to produce an output current pulse rising to several hundred kiloamperes in approximately ten nanoseconds in a short circuit load, the accompanying loss of energy being of secondary importance. Additionally, the output circuit needs to be able to sustain high-voltages (MV) rising in a few nanoseconds across a purely resistive load.