Fail safe controller

Claim 1

A FAIL SAFE CONTROLLER WHICH IS RESPONSIVE TO CHANGES IN THE IMPEDANCE OF A SENSOR FOR SELECTIVELY ENERGIZING A LOAD, SAID CONTROLLER COMPRISING: A POWER CIRCUIT INCLUDING A SILICON CONTROLLED RECTIFIER AND MEANS FOR INTERCONNECTING THE ANODE-CATHODE CIRCUIT OF SAID RECTIFIER WITH SAID LOAD FOR SELECTIVELY SWITCHING THE FLOW OF ELECTRIC POWER THERETO; MEANS FOR CONNECTING SAID POWER CIRCUIT TO AN A.C. SOURCE; A VOLTAGE DIVIDER INCLUDING A SENSING IMPEDANCE SERIALLY CONNECTED WITH A REFERENCE IMPEDANCE; A TRANSFORMER INCLUDING A PRIMARY WINDING CONNECTED TO SAID SOURCE AND A SECONDARY WINDING HAVING AN INTERMEDIATE TAP; A SECONDARY WINDING CIRCUIT INCLUDING SAID SECONDARY WINDING FOR APPLYING A.C. TO SAID DIVIDER IN PHASE WITH THE A.C. APPLIED TO SAID POWER CIRCUIT, SAID SECONDARY WINDING CIRCUIT INCLUDING SUBSTANTIAL SOURCE IMPEDANCE IN SERIES WITH SAID DIVIDER; A TRANSISTOR THE EMITTER TERMINAL OF WHICH IS CONNECTED TO SAID INTERMEDIATE TAP AND THE BASE TERMINAL OF WHICH IS CONNECTED TO SAID VOLTAGE DIVIDER AT A JUNCTION BETWEEN SAID REFERENCE IMPEDANCE AND SAID SENSING IMPEDANCE, CONDUCTION IN THE COLLECTOR-EMITTER CIRCUIT OF SAID TRANSISTOR THEREBY BEING A FUNCTION OF THE RELATIVE IMPEDANCE VALUES OF SAID REFERENCE IMPEDANCE AND SAID SENSING IMPEDANCE; AND CIRCUIT MEANS CONNECTING THE GATE-CATHODE CIRCUIT OF SAID SILICON CONTROLLED RECTIFIER BETWEEN THE END OF SAID SENSING IMPEDANCE WHICH IS OPPOSITE SAID JUNCTION AND THE COLLECTOR TERMINAL OF SAID TRANSISTOR FOR PROVIDING TRIGGERING CURRENT TO SAID SILICON CONTROLLED RECTIFIER UNDER CONTROL OF SAID TRANSISTOR WHEREBY SHORTING OF SAID SENSING IMPEDANCE SHUNTS THE GATECATHODE CIRCUIT OF SAID SILICON CONTROLLED RECTIFIER THEREBY DEENERGIZING SAID LOAD.