Abstract: A tap changing system for operation with a transformer and featuring a special group of gate-controlled electronic devices that operate as a circuit breaker and recloser such that, after half-cycle of short-circuit current, said special group is transferred to the OFF-state, whereby the tap changer winding is open circuited; the advantage being that only the special group of devices need be rated to sustain short-circuit conditions; a further feature is the concept of Discrete-Cycle Modulation (DCM) whereby tap voltage magnitudes are obtainable in increments intermediate the physical tap winding voltage magnitudes.