Transductor
A transductor is type of magnetic amplifier used in power systems for compensating reactive power. It consists of an iron-cored inductor with two windings - a main winding through which an alternating current flows from the power system, and a secondary control winding which carries a small direct current. By varying the direct current, the iron core of the transductor can be arranged to saturate at different levels and thus vary the amount of reactive power absorbed.
Transductors were widely used before the advent of solid-state electronics but today have been largely replaced by power electronic devices such as the Static VAR compensator and STATCOM.
A formerly common use for Transductors was in CRT displays, to correct a distortion called pincushion distortion, where the side of the picture bowed in at the centre as a result of the geometry of large deflection angles. It would have one set of windings in the horizontal deflection circuit and the other set in the vertical; the action of the tranductor caused the deflection waveforms to modulate each other - reducing line scan at the top and bottom and similarly on the vertical waveform.
