The present invention relates to a synchronous rectifier comprising at least one rectifier cell (Gi), to which power is supplied via a secondary winding (L4i) of a transformer (Tr1) arranged between the input connections (E1, E2) of the synchronous rectifier. The rectifier cell (Gi) comprises a bipolar main switch (T1) operated in the inverse mode, wherein an energy store (C2) is provided in the base line of the bipolar main switch (T1), which energy store, in conjunction with an auxiliary switch (T2) which is concomitantly controlled by the relevant secondary winding (L4i) for the bipolar main switch (T1), ensures that the main switch (T1) is switched off prior to the end of the inverse phase.