Solid state anticipating temperature controller

Claim 1

APPARATUS FOR CONTROLLING A HEATER, COMPRISING IN COMBINATION: (A) AN ELECTRICAL BRIDGE HAVING THEREIN A THERMISTOR THERMALLY COUPLED TO SAID HEATER FOR SENSING THE TEMPERATURE THEREOF, SAID BRIDGE PRODUCING A CONTROL SIGNAL HAVING A MAGNITUDE VARYING WITH DEVIATION OF THE SENSED TEMPERATURE FROM THE PREDETERMINED VALUE, (B) A FIRST SILICON CONTROLLED RECTIFIER HAVING FIRST GATE, FIRST CATHODE AND FIRST ANODE ELECTRODES, (C) AN INPUT CIRCUIT CONNECTED FOR APPLYING SAID CONTROL SIGNAL TO SAID FIRST GATE AND SAID FIRST CATHODE ELECTRODE, SAID INPUT CIRCUIT INCLUDING A SERIES CAPACITOR, (D) A.C. POWER SUPPLY TERMINALS, (E) SWITCHING MEANS RESPONSIVE TO CONDUCTION OF SAID FIRST SILICON CONTROLLED RECTIFIER FOR CONNECTING SAID HEATER ACROSS SAID POWER SUPPLY TERMINALS, SAID SWITCHING MEANS INCLUDING (1) A SECOND POWER SILICON CONTROLLED RECTIFIER HAVING SECOND GAGE, SECOND CATHODE, AND SECOND ANODE ELECTRODES, (2) AND A RECTIFYING DIODE BRIDGE, SAID DIODE BRIDGE HAVING AN INPUT DIAGONAL CONNECTED IN SERIES WITH SAID HEATER AND SAID POWER SUPPLY AND A CONTROL DIAGONAL CONNECTED TO SAID SECOND ANODE AND SAID SECOND CATHODE, (F) AND A FEEDBACK NETWORK, ENERGIZED BY AN APPLICATION OF POWER TO SAID HEATER, FOR APPLYING A CHARGE TO SAID CAPACITOR OPPOSING CONDUCTION OF SAID FIRST RECTIFIER, SAID NETWORK INCLUDING RESISTANCE MEANS FOR CONTROLLING THE CHARGING AND DISCHARGING TIME CONSTANTS OF SAID CAPACITOR.