Abstract: The present invention is a DC motor drive circuit in which each end of a center tapped supply transformer is connected through a pair of back-to-back thyristors to corresponding ends of a center tapped choke coil. The motor armature is connected between the two center taps. After each zero crossing of an AC input signal, a ramp signal is generated. The ramp is comprised of two linear segments of different slopes to improve the linearity of the output of the thyristors as the conduction angle approaches the zero crossing point. Comparator circuits are responsive to the ramp signal and a command signal for generating trigger pulses to the thyristors. The comparators are biased so that with no command signal present, the comparators operate the thyristors to produce a small alternating loop current through the transformer and the choke with each half cycle of the AC input signal. This maintains conduction through all the thyristors without dithering the motor armature.