JPS5473625A - Stroboscopic trigger circuit - Google Patents

Abstract

PURPOSE:To prevent the malfunction and destruction of a thyristor by inputting a gate signal to the gate of the thyristor for a period of time reguired for triggering at least a flash tube. CONSTITUTION:Main capacitor 13 and trigger capacitor 16 are charged by making the electric power SW11 ON via boosting circuit 12. With input of synchro-contact signal into buffer circuit 19, its output is reversed from H to L to make transistor 22 ON and input gate signal to the base of SCR 17. Thus SCR is made ON to discharge the electric load of the trigger capacitor 16 such that the discharge electric current flows through the primary side of trigger transformer 18, and the high voltage produced at the secondary side is caused to apply to trigger electrode 14a so as to make flash tube 14 emit light. Meanwhile, when the output of the buffer circuit 19 reaches L, capacitor 21 begins to changeitself. When the flash tube begins to discharge or immediately thereafter, it is charged to the predetermined level so that the transistor 22 is made OFF. This OFF eliminates the gate signal, and SCR 17 is short-circuited and made OFF by the discharge of the flash tube 14. Therefore, although the electric current flows through C15, 16 thereafter, SCR is not made ON.