sentences:  This contains a combination of capacitors and transformers and is used to mate the power unit to the work coil.Also known as the inductor, the coil is used to transfer the energy from the power unit and work head to the work piece.Inductors range in complexity from a simple wound solenoid consisting of a number of turns of copper tube wound around a mandrel, to a precision item machined from solid copper, brazed and soldered together.