Voltage control system

Abstract From the Canadian patent

A system for deriving a substantially constant output voltage from an alternating supply voltage of variable frequency and amplitude includes circuit responsive to negative-going zero crossing points of the supply for generating control signals whose duration depends on the number of points occurring in a predetermined time. A switching arrangement is responsive to the signals to interrupt the supply voltage the, interrupted voltage being applied through a transformer to an output circuit from which a d.c. output voltage is applied to spark igniters.