JPS6489196A - Lighting device for ac type flash lamp - Google Patents

Abstract

PURPOSE:To light a flash lamp invariably with the fixed voltage by providing a means controlling a phase control element so that a phase control element control circuit detects the fluctuation of the input voltage or the fluctuation of the output voltage and the fixed voltage is charged in a charging and discharging capacitor in a resonance circuit. CONSTITUTION:When a phase control element 14 is turned on, the voltage of an AC power source 1 is resonated by a resonance circuit 11, and the voltage can be varied by selecting the values of a choke coil 2 and a capacitor 3. When the preset voltage is charged across the capacitor 3, a bipolar switch element control circuit 4 turns the gate of a bipolar switch element 5 on, charges charged in a capacitor 6 on the primary side of the transformer 7 of a trigger circuit 12 are discharged, the high voltage is induced on a trigger electrode 9 to trigger a PXA 10. There is a slight time lag before the discharge current by the energy of the capacitor 3 flows through the PXA 10, and the element 5 is kept conducting during this time. When the potential of the capacitor 3 is decreased and the current flowing through the element 5 becomes 0, the PXA 10 is turned off.