Scr bidirectional switch apparatus having variable impedance input control circuit

Claim 1

CONTROL APPARATUS COMPRISING: FIRST AND SECOND TERMINALS; A SOURCE OF BIDIRECTIONAL ENERGY AND A LOAD SERIALLY CONNECTED BETWEEN SAID TERMINALS; FIRST AND SECOND CONTROLLED CURRENT CARRYING DEVICES EACH HAVING INPUT, OUTPUT AND CONTROL ELECTRODES; MEANS CONNECTING SAID FIRST AND SECOND DEVICES INPUT AND OUTPUT ELECTRODES TO SAID TERMINALS SO THAT SAID FIRST AND SECOND DEVICES ARE CONNECTED IN PARALLELINVERSE RELATION; VOLTAGE BRIDGE RECTIFICATION MEANS HAVING BIDIRECTIONAL INPUT TERMINALS AND UNIDIRECTIONAL OUTPUT TERMINALS; A PORTION OF SAID BRIDGE MEANS CONNECTING SAID FIRST AND SECOND DEVICES CONTROL ELECTRODES, RESPECTIVELY, TO SAID FIRST AND SECOND TERMINALS; MEANS CONNECTING SAID INPUT TERMINALS TO SAID FIRST AND SECOND TERMINALS; A THIRD CONTROLLED CURRENT CARRYING DEVICE HAVING INPUT, OUTPUT AND CONTROL ELECTRODES; MEANS CONNECTING SAID THIRD DEVICE INPUT ELECTRODE TO ONE OF SAID OUTPUT TERMINALS; MEANS CONNECTING SAID THIRD DEVICE OUTPUT ELECTRODE TO ANOTHER OF SAID OUTPUT TERMINALS; MEANS INCLUDING ENERGY STORAGE MEANS CONNECTED ACROSS SAID OUTPUT TERMINALS; FIRST IMPEDANCE MEANS CONNECTED BETWEEN SAID THIRD DEVICE CONTROL ELECTRODE AND OUTPUT ELECTRODE; SECOND IMPEDANCE MEANS CONNECTED ACROSS SAID FIRST IMPEDANCE MEANS INCLUDING SWITCHING MEANS HAVING A CONTROL ELECTRODE CONNECTED TO SAID ENERGY STORAGE MEANS, FOR VARYING THE INPUT IMPEDANCE TO SAID THIRD DEVICE CONTROL ELECTRODE BY SWITCHING SAID SECOND IMPEDANCE MEANS OUT OF CIRCUIT WITH SAID FIRST IMPEDANCE MEANS; AND A SOURCE OF CONTROL SIGNAL CONNECTED ACROSS SAID FIRST IMPEDANCE MEANS.