Position control system with heated resistor feedback network

Claim 1

IN A POSITION CONTROL SYSTEM FOR MAINTAINING THE MAGNITUDE OF A CONDITION AT A PREDETERMINED DESIRED VALUE BY OPERATING A FINAL CONTROL ELEMENT IN ONE DIRECTION OR THE OTHER VARY IN ONE DIRECTION OR THE OTHER THE MAGNITUDE OF A CONDITION-CONTROLLING EFFECT, ACTUATING MEANS FOR THE FINAL CONTROL ELEMENT, SELECTOR MEANS FOR CONTROLLING THE DIRECTION OF OPERATION OF SAID ACTUATING MEANS, AT LEAST TWO PAIRS OF RESISTORS CONNECTED IN A BRIDGE NETWORK, ONE PAIR OF SAID RESISTORS HAVING A LOW THERMAL INERTIA AND THE OTHER PAIR OF SAID RESISTORS HAVING A HIGH THERMAL INERTIA, SAID BRIDGE NETWORK INCLUDING ONE OF SAID RESISTORS IN EACH ARM THEREOF, MEANS RESPONSIVE TO SAID SELECTOR MEANS AND INDEPENDENT OF SAID ACTUATING MEANS FOR HEATING ONE RESISTOR OF EACH PAIR OF SAID RESISTORS WHEN SAID SELECTOR MEANS CONTROLS SAID ACTUATING MEANS IN ONE DIRECTION AND FOR HEATING THE OTHER RESISTOR OF EACH PAIR OF SAID RESISTORS WHEN SAID SELECTOR MEANS CONTROLS SAID ACTUATING MEANS IN THE OTHER DIRECTION, MEANS CONNECTED BETWEEEN SAID PAIRS OF RESISTORS FOR SELECTING THE RELATIVE EFFECTIVENESS OF EACH PAIR IN PRODUCING THE OUTPUT SIGNAL FROM SAID BRIDGE NETWORK, MEANS FOR PRODUCING A DEVIATION SIGNAL CORRESPONDING IN POLARITY AND MAGNITUDE TO THE DIRECTION AND EXTENT OF DEVIATION OF SAID MAGNITUDE OF SAID CONDITION FROM THE DESIRED VALUE, AND MEANS RESPONSIVE TO THE DIFFERENCE BETWEEN SAID DEVIATION SIGNAL AND SAID BRIDGE NETWORK OUTPUT SIGNAL FOR ENERGIZING SAID SELECTOR MEANS FOR OPERATION OF SAID ACTUATING MEANS IN OPERATING THE FINAL CONTROL ELEMENT TO RETURN SAID MAGNITUDE OF SAID CONDITION TO SAID DESIRED VALUE.