1. A two-stage magnetic amplifier comprising: a. a transformer coupled to a source of alternating voltage and including plural secondary windings; b. a first stage comprising: i. a first of said secondary windings; and ii. a first saturable magnetic core having first and second windings disposed thereon; c. a second stage comprising: i. a second of said secondary windings; and ii. a second saturable magnetic core having third and fourth windings disposed thereon; d. first means including unidirectional conducting means connecting said first and fourth windings in series with one another and across said first secondary winding, said first means enabling said first and fourth windings to be energized by the voltage appearing on the first secondary winding during one half cycle of the alternating voltage; e. second means including unidirectional conducting means connecting said third winding in series with said second secondary winding and a load, said second means enabling said third winding to be energized by the voltage appearing on the second secondary winding during the alternate half cycle of the alternating voltage; and f. third means applying direct voltage to said second winding, said third means including: i. switch means, operative in synchronism with the alternating voltage, enabling the second winding to be energized by the direct voltage during the alternate half cycle of the alternating voltage.