System for triggering flashlamp

Claim 1

AN ELECTRICAL CIRCUIT FOR OPERATING A PHOTOGRAPHIC FLASHLAMP COMPRISING (A) A LIGHT SENSITIVE SILICON CONTROLLED RECTIFIER, (B) A STORAGE CAPACITOR, (C) A TRANSFORMER, (D) MEANS CONNECTING SAID CAPACITOR AND THE PRIMARY WINDING OF SAID TRANSFORMER IN SERIES WITH THE ANODE AND CATHODE OF SAID RECTIFIER, (E) MEANS FOR CHARGING SAID CAPACITOR, (F) MEANS FOR BIASING SAID RECTIFIER AND MAINTAINING IT IN A LIGHT RESPONSIVE CONDITION, WHEREBY WHEN A LIGHT SIGNAL STRIKES SAID RECTIFIER IT BECOMES CONDUCTIVE AND SAID CAPACITOR DISCHARGES THROUGH IT AND THROUGH SAID PRIMARY WINDING TO PRODUCE AN ELECTRICAL PULSE IN THE SECONDARY WINDING OF SAID TRANSFORMER, (G) SAID BIASING AND MAINTAINING MEANS INCLUDING IMPEDANCE ELEMENTS CONNECTED BETWEEN THE GATE ELECTRODE AND THE CATHODE OF SAID RECTIFIER, SAID IMPEDANCE ELEMENTS BEING OF SUFFICIENT VALUE TO MAINTAIN THE SENSITIVITY OF SAID RECTIFIER AT A DESIRED LEVEL, (H) ALTERNATIVELY OPERABLE MEANS FOR REDUCING THE IMPEDANCE BETWEEN THE GATE ELECTRODE AND CATHODE OF SAID RECTIFIER TO RENDER IT SUBSTANTIALLY INSENSITIVE TO LIGHT, AND (I) MEANS FOR APPLYING AN ELECTRICAL TRIGGER PULSE BETWEEN THE GATE ELECTRODE AND THE CATHODE OF SAID RECTIFIER IN RESPONSE TO CLOSING OF AN EXTERNAL SWITCH DURING TIMES WHEN SAID ALTERNATIVELY OPERABLE MEANS IS OPERATIVE.