Fail-safe reflected light-responsive control circuit

Claim 1

A CONTROL CIRCUIT COMPRISING: A TRANSFORMER HAVING A PLURALITY OF SECONDARY WINDINGS INCLUDING A FIRST, SECOND, THIRD, AND FOURTH WINDING, SAID THIRD WINDING HAVING A CENTER TAP TO CIRCUIT GROUND; AN ILLUMINATION SOURCE BRIDGING SAID FIRST WINDING, SAID SOURCE BEING DIRECTED ONTO A LIGHT REFLECTIVE SURFACE; A PAIR OF COLD CATHODE RELAY TUBES, EACH TUBE HAVING AN ANODE, A STARTING ANODE, AND A CATHODE, SAID CATHODES BEING DIRECTLY CONNECTED TO CIRCUIT GROUND; A VOLTAGE REGULATING MEANS INCLUDING A SERIES CONNECTED RESISTOR AND A PAIR OF NEON TUBES SHUNTING SAID SECOND WINDING AND A LIGHT SOURCE SHUNTING SAID FOURTH WINDING, SAID REGULATING MEANS AND SAID PAIR OF RELAY TUBES BEING ENCLOSED WITHIN A LIGHT-TIGHT CONTAINER; A PAIR OF CURRENT RESPONSIVE DEVICES, EACH OF SAID DEVICES HAVING A NORMALLY OPEN ELECTRICAL CONTACT AND SAID CONTACTS BEING SERIES CONNECTED; AND CIRCUIT MEANS CONNECTING EACH OF SAID STARTING ANODES TO SAID VOLTAGE REGULATING MEANS THROUGH A RESISTOR AND EACH OF SAID ANODES TO SAID THIRD WINDING THROUGH A SERIES CONNECTED RESISTOR AND ONE OF SAID CURRENT RESPONSIVE, DEVICES, SAID CIRCUIT MEANS INCLUDING A VOLTAGE DIVIDER SHUNTING AT LEAST A PORTION OF SAID VOLTAGE REGULATING MEANS, SAID DIVIDER HAVING THEREIN A SERIES CONNECTED RESISTOR AND A PHOTOCONDUCTOR AND SAID PHOTOCONDUCTOR BEING RESPONSIVE TO THE REFLECTED LIGHT OF SAID ILLUMINATION SOURCE.