Lamp dimming circuit

Claim 1

A CIRCUIT FOR AUTOMATICALLY VARYING THE BRIGHTNESS OF A PILOT LAMP TO PRODUCE A SUBSTANTIALLY CONSTANT BRIGHTNESS CONTRAST BETWEEN THE PILOT LAMP AND THE AMBIENT LIGHT, INCLUDING IN COMBINATION, A TRANSISTOR HAVING A FIRST ELECTRODE COUPLED TO A REFERENCE POTENTIAL, A SECOND ELECTRODE AND A CONTROL ELECTRODE, CONTROL CIRCUIT MEANS COUPLED TO SAID CONTROL ELECTRODE FOR SUPPLYING A CONTROL CURENT THERETO, SAID CONTROL CIRCUIT MEANS INCLUDING LIGHT SENSITIVE RESISTANCE MEANS POSITIONED TO RECEIVE THE AMBIENT LIGHT AND BEING RESPONSIVE THERETO TO VARY THE MAGNITUDE OF SAID CONTROL CURRENT DIRECTLY AS THE MAGNITUDE OF THE AMBIENT LIGHT VARIES, LIGHTING CIRCUIT MEANS INCLUDING FIRST AND SECOND PILOT LAMPS COUPLED TO SAID SECOND ELECTRODE, CURRENT SUPPLY CIRCUIT MEANS COUPLED TO SAID LIGHTNING CIRCUIT MEANS AND ADAPTED TO SUPPLY A LIGHTNING CURRENT TO SAID LIGHTNING CIRCUIT MEANS AND SAID TRANSISTOR, SAID CURENT SUPPLY CIRCUIT MEANS INCLUDING RESISTANCE MEANS COUPLED TO SAID FIRST PILOT LAMP FOR SUPPLYING SAID LIGHTNING CURRENT THERETO, SAID CURENT SUPPLY CIRCUIT MEANS FURTHER INCLUDING SWITCHING MEANS COUPLED TO SAID RESISTANCE MEANS AND SAID SECOND PILOT LAMP, OPERATING MEANS COUPLED TO SAID SWITCHING MEANS FOR INTERMITTENTLY ENERGIZING SAIS SWITCHING MEANS, SAID SWITCHING MEANS IN SAID ENERGIZED CONDITION BEING ADAPTED TO SUPPLY SAID LIGHTNING CURRENT, SAID SWITCHING MEANS BEING RESPONSIVE TO ENERGIZATION BY SAID OPERATING MEANS TO DECOUPKE SAID RESISTANCE MEANS FROM SAID FIRST PILOT LAMP AND TO COUPLE SAID SECOND PILOT LAMP IN SERIES WITH SAID FIRST PILOT LAMP, WHEREBY SAID LIGHTNING CURRENT FLOWS THROUGH BOTH SAID FIRST AND SECOND PILOT LAMPS AND SAID TRANSISTOR, SAID TRANSISTOR ACTING TO REGLATE SAID LIGHTING CURRENT IN RESPONSE TO SAID VARIATION IN THE MAGNITUDE OF SAID CONTROL CURRENT WHEREBY THE BRIGHTNESS OF SAID FIRST AND SECOND PILOT LAMPS IS VARIED TO MAINTAIN A SUBSTANTIALLY CONSTANT BRIGHTNESS CONTRAST BETWEEN SAID FIRST AND SECOND PILOT LAMPS AND THE AMBIENT LIGHT.