Analytical and experimental considerations in the constant voltage transformer are presented. The constant voltage transformer consists of a linear reactor, a linear transformer, a capacitor, a triac and a feedback circuit. The feedback circuit is used to make the triac fire precisely at any angle from zero to ??/2 so as to keep output voltage constant. In this paper, an analysis of this circuit is presented, in which the harmonic currents generated in the triac are neglected and the output voltage is assumed to be kept constant. The experimental results agree welt with the theoretical value in respect of the load characteristic, the voltage characteristic, the power factor and the jumping phenomenon.