Electric gating circuits

Claim 1

AN ELECTRIC GATING CIRCUIT COMPRISING A PAIR OF TERMINALS, A TRANSISTOR HAVING A CONTROL ELECTRODE AND FIRST AND SECOND FURTHER ELECTRODES, MEANS CONNECTING SAID FIRST AND SECOND FURTHER ELECTRODES ONE TO EACH OF SAID PAIR OF TERMINALS, MEANS CONECTING SAID FIRST AND SECOND FURTHER ELECTRODES TO A COMMON POINT, AND MEANS TO APPLY, IN RESPONSE TO GATING SIGNALS APPLIED THERETO, CONTROL SIGNALS BETWEEN THE CONTROL ELECTRODE AND THE COMMON POINT, SAID LAST-MENTIONED MEANS COMPRISING A TRANSFORMER HAVING A PRIMARY WINDING AND A SECONDARY WINDING, MEANS TO APPLY SAID GATING SIGNALS TO THE PRIMARY WINDING OF THE TRANSFORMER, A CAPACITOR, MEANS CONNECTING SAID CAPACITOR IN SERIES WITH THE SECONDARY WINDING OF THE TRANSFORMER BETWEEN SAID COINTROL ELECTRODE AND SAID COMMON POINT, A RECTIFIER ELEMENT, AND MEANS CONNECTING SAID RECTIFIER ELEMENT IN PARALLEL WITH SAID SERIES-CONNECTED CAPACITOR AND SECONDARY WINDING, THE CIRCUIT BEING SO ARRANGED THAT WHEN A GATING SIGNAL IS APPLIED TO THE PRIMARY WINDING OF THE TRANSFORMER THE CAPACITOR IS CHARGED BY WAY OF SAID RECTIFIER ELEMENT, AND A FORWARD BIAS IS APPLIED BETWEEN THE CONTROL ELECTRODE AND THE FIRST FURTHER ELECTRODE AND BETWEEN THE CONTROL ELECTRODE AND THE SECOND FURTHER ELECTRODE OF THE TRANSISTOR, SO THAT A BI-DIRECTIONAL CURRENT PATH IS THEN ESTABLISHED BETWEEN SAID PAIR OF TERMINALS, WHILE FOR A PERIOD FOLLWOING THE CESSATION OF A GATING SIGNAL THE CHARGE ON THE CAPACITOR PROVIDES A REVERSE BIAS BETWEEN THE CONTROL ELECTRODE AND THE FIRST FURTHER ELECTRODE AND BETWEEN THE CONTROL ELECTRODE AND THE SECOND FURTHER ELECTRODE OF THE TRANSISTOR.