Flash lamp circuit

Claim 1

Apparatus responsive to a gating signal and a trigger signal supplied by an external controller for firing a flash lamp, said flash lamp comprising an envelope containing an ionizable gas, a pair of primary electrodes extending into said envelope, and a trigger electrode adapted to cause partial ionization of the gas within said envelope upon the application of a high voltage pulse thereto, said apparatus comprising a storage capacitor connected across said pair of primary electrodes, a trigger capacitor, a trigger transformer having a primary winding and a secondary winding, said primary winding being connected to said trigger capacitor and said secondary winding being connected to said trigger electrode, a first voltage souce connected to charge said storage capacitor, a second voltage source connected to charge said trigger capacitor, first gating means including a control terminal and arranged to provide a discharge path for said trigger capacitor through said trigger transformer primary winding upon the application of said trigger signal to said control terminal, a high voltage pulse being generated across said secondary winding in response to the discharge of said trigger capacitor, voltage sensing means responsive to the voltage across said storage capacitor for supplying a first signal when the voltage across said storage capacitor is greater than a predetermined value, connecting means for providing a path for said gating signal from said external controller when said capacitors are to be charged, bistable latching means having a first input terminal connected to said voltage sensing means and a second input terminal connected to said connecting means, said latching means being responsive to said first signal for assuming a first state and responsive to said gating signal from said connecting means for assuming a second state, and second gating means connected to said storage capacitor aNd responsive to the state of said latching means for providing a charging path for said storage capacitor only when said latching means is in said second state.