Silicon controlled rectifier dimmer

Claim 1

ELECTRICAL CONTROL APPARATUS FOR CONTROLLING THE CURRENT APPLIED FROM FIRST AND SECOND INPUT VOLTAGE TERMINALS TO AN INCANDESCENT LAMP LOAD COMPRISING SOLID STATE CONTROLLED RECTIFIERS CONNECTED IN SERIES WITH SAID INCANDESCENT LAMP LOAD ACROSS SAID INPUT VOLTAGE TERMINALS FOR CONTROLLING ALTERNATING CURRENT PASSING THROUGH SAID LOAD, PHASE SHIFTING MEANS CONNECTED TO SAID RECTIFIERS FOR APPLYING FIRING PULSES TO SAID RECTIFIERS VARIABLE IN PHASE OVER EACH HALF CYCLE, INPUT CONTROL MEANS CONNECTED TO SAID PHASE SHIFTING MEANS FOR VARYING THE TIME OF FIRING OF SAID RECTIFIERS, A RESISTANCE NETWORK CONNECTED ACROSS SAID SOLID STATE CONTROLLED RECTIFIERS AND TO SAID FIRST INPUT VOLTAGE TERMINAL, RECTIFYING MEANS HAVING A DIRECT CURRENT OUTPUT CONNECTED TO SAID PHASE SHIFTING MEANS AND HAVING AN ALTERNATING CURRENT INPUT CONNECTED BETWEEN AN INTERMEDIATE POINT OF SAID NETWORK AND SAID SECOND INPUT VOLTAGE TERMINAL, A PORTION OF THE RESISTOR NETWORK CONNECTED TO SAID FIRST INPUT TERMINAL HAVING A SUBSTANTIALLY GREATER RESISTANCE THAN THE REMAINING PORTION AND PASSING A SUBSTANTIALLY CONSTANT CURRENT OVER THE RANGE OF ILLUMINATION WHILE SAID REMAINING PORTION PASSES CURRENT VARYING WITH THE CONDUCTIVITY OF THE RECTIFIERS TO PROVIDE ADJUSTMENT OF THE RELATION OF SAID INPUT CONTROL MEANS AND LAMP LOAD ILLUMINATION OVER THE ENTIRE ILLUMINATION RANGE TO ATTAIN THE DESIRED RELATION BETWEEN THE INPUT CONTROL MEANS AND THE ILLUMINATION OF THE LAMP LOAD.