Lamp driver circuits

Claim 1

A SURGE PROTECTION CIRCUIT FOR CONTROLLING A CURRENT THROUGH AN INDICATOR LAMP HAVING A FILAMENT THAT EXHIBITS SUBSTANTIALLY LESS RESISTANCE WHEN COLD THAT HOT, COMPRISING IN COMBINATION, MEANS PROVIDING A SOURCE OF ALTERNATING SIGNALS HAVING A HALF PERIOD OF A PREDETERMINED DURATION, A CONTROLLED RECTIFIER HAVING AN ANODE ELECTRODE AND A CATHODE ELECTRODE THAT DEFINES A UNIDIRECTIONAL CURRENT CONDUCTIVE PATH THROUGH SAID RECTIFIER, AND A GATE ELECTRODE THAT CONTROLS THE ACTIVATION OF SAID CONDUCTIVE PATH, MEANS FOR APPLYING SAID ALTERNATING SIGNALS TO SAID INDICATOR LAMP SOLELY THROUGH SAID CONTROLLED RECTIFIER BY COUPLING THE FILAMENT OF SAID INDICATOR LAMP IN SERIES WITH THE CONDUCTIVE PATH OF SAID CONTROLLED RECTIFIER AND SAID SOURCE OF ALTERNATING SIGNALS, A PHASE SHIFTER CIRCUIT COUPLED TO SAID SOURCE OF ALTERNATING SIGNALS TO SHIFTS THE PHASE OF THE INITIAL ALTERNATING SIGNALS FROM SAID SOURCE SO THAT SAID PHASE SHIFTED AND INITIAL ALTERNATING SIGNALS ARE COINCIDENTALLY POSITIVE FOR A PERIOD OF TIME LESS THAN SAID PREDETERMINED HALF PERIOD, RECTIFYING MEANS COUPLED TO SAID PHASE SHIFTER CIRCUIT FOR RECTIFYING SAID PHASE SHIFTED ALTERNATING SIGNALS TO PROVIDE POSITIVE PHASE SHIFTED PULSES, AN OR GATE HAVING AN OUTPUT TERMINAL COUPLED TO THE GATE ELECTRODE OF SAID CONTROLLED RECTIFIER, AND HAVING A PAIR OF INPUT TERMINALS, MEANS FOR COUPLING SAID RECTIFYING MEANS TO ONE OF SAID INPUT TERMINALS OF SAID OR GATE FOR APPLYING SAID POSITIVE PHASE SHIFTED PULSES TO SAID GATE ELECTRODE TO ACTIVATE THE CONDUCTIVE PATH OF SAID CONTROLLED RECTIFIER TO PASS CURRENT PULSES THROUGH SAID INDICATOR LAMP WHEN BOTH SAID ORIGINAL ALTERNATING SIGNALS AND SAID PULSES EXHIBIT A POSITIVE PHASE,