Abstract :
Two ways of obtaining feedback in magnetic amplifiers are studied. One, termed external feedback, employs a bridge rectifier and separate feedback coils, while the other, termed self feedback, uses two rectifiers so disposed that separate feedback windings are unnecessary. Commutation of the rectifiers, apparently not considered heretotore, is shown to be of major importance. The calculated currents are confirmed satisfactorily, both in shape and magnitude, by experimental checks. The two feedback methods are compared, and it is found that self feedback is advantageous.
