Abstract: Electrical circuitry for delivering to a flashtube a series of flash-producing electrical pulses, the circuitry comprising energy circuitry means for repeatedly storing electrical energy and discharging the energy in the form of such pulses through the flashtube, each pulse producing a flash, each flash being grouped in a flash cycle synchronized with a cycle of an AC voltage source, the energy circuitry means comprising first and second capacitors connected by a switching element responsive to the difference between a first voltage at the junction between the first capacitor and the switching element and a second voltage on the second capacitor, the energy circuitry means stepping up the voltage discharged across the flashtube by the second capacitor, and firing circuitry means for receiving during each flash cycle a portion of the energy discharged by the energy circuitry means, to initiate each flash, the firing circuitry means being timed to initiate the flash, thereby reducing the second voltage upon dis