sentences:  The unit needs to be rated at the correct kilovolt-ampere (kVA) to supply the necessary current to the oscillator.Early rectifier systems featured valve rectifiers such as GXU4 (high power high voltage half wave rectifier) but these were ultimately superseded by high voltage solid state rectifiers.The oscillator circuit is responsible for creating the elevated frequency electric current, which when applied to the work coil creates the magnetic field which heats the part.