Patent ID: 6903642

Claim:
In combination, a transformer including at least one core of ferromagnetic material, a first winding across which an exciting voltage is to be applied, the first winding provided on one of the cores, a second winding provided on one of the cores, the second winding including first and second terminals across which a voltage is to be induced in response to the exciting voltage, a first device for providing a relatively higher impedance between the first and second terminals of the second winding, the first device coupled between the first and second terminals, one of the terminals of the second winding adapted for coupling to a relatively lower impedance, third, fourth and fifth windings, the third winding having first and second terminals, the fourth winding having first and second terminals, the fifth winding having first and second terminals, the third and fourth windings being wound on one of the cores with a first polarity, and the fifth winding being wound on one of the cores with a second polarity opposite to the first polarity, a second device for providing a relatively higher impedance between at least one pair of the following pairs of terminals: the first and second terminals of the third winding; the first and second terminals of the fourth winding; and, the first and second terminals of the fifth winding, one of the first and second terminals of each of the third, fourth and fifth windings also adapted for coupling to the relatively lower impedance.