Abstract: Solid state ignition circuitry for transmitting impulse voltages, produced by .[.a.]. magneto .Iadd.means .Iaddend.associated with an internal combustion engine, to a transformer, which, in turn, generates a high voltage impulse to produce sparks in the spark plugs of the engine. The circuitry includes two silicon controlled rectifiers adapted to control the discharge of a capacitor through the transformer. The capacitor charges during one part of a given time period, e.g., the positive half cycle of alternating current produced by the magneto, and the silicon controlled rectifiers are adapted to discharge the capacitor during the other part of such time period, e.g., the negative half cycle of such current. The particular instant at which the capacitor discharges can be varied by .Iadd.adjustable .Iaddend.means .Iadd.for applying controlled input voltages to the control electrodes of .[.of a potentiometer, which is associated with.]. the silicon controlled rectifiers.