Constant output amplifier including light responsive feedback means

Claim 1

A CONSTANT OUTPUT AMPLIFIER COMPRISING A FIRST STAGE AND A SECOND STAGE COMMON-EMITTER AMPLIFIER COUPLED TO AN EMITTER-FOLLOWER STAGE, A POTENTIAL SOURCE FOR SAID AMPLIFIER, THE TRANSISTOR OF EACH STAGE HAVING BASE, COLLECTOR AND EMITTER ELECTRODES THE NEGATIVE POLE OF SAID POTENTIAL SOURCE CONNECTED TO THE COLLECTOR ELECTRODE AND BASE ELECTRODE OF THE TRANSISTOR OF EACH OF SAID STAGES AND THE POSITIVE POLE CONNECTED TO THE EMITTER ELECTRODE OF THE TRANSISTOR OF EACH OF SAID STAGES, THE SIGNAL INPUT APPLIED ACROSS THE BASE AND EMITTER OF SAID FIRST STAGE AND OUTPUT SIGNAL TAKEN AT THE EMITTER OF THE EMITTER-FOLLOWER, A NEGATIVE FEEDBACK LOOP INCLUDING A SERIES CONNECTED CAPACITOR AND FEEDBACK ELEMENT COUPLING THE EMITTER OF SAID EMITTERFOLLOWER TO THE EMITTER OF THE FIRST STAGE OF THE COMMONEMITTER AMPLIFIER, THE FEEDBACK ELEMENT COMPRISING A LIGHT SENSITIVE RESISTOR HAVING SERIES CONNECTED TUNGSTEN LAMPS FACED IN ITS SURFACE, A VOLTAGE MULTIPLIER-RECTIFIER, A D.-C. AMPLIFIER, THE INPUT OF SAID RECTIFIER COUPLED TO THE EMITTER OF THE EMITTER-FOLLOWER AND ITS OUTPUT APPLIED ACROSS THE BASE AND EMITTER ELECTRODES OF THE D.-C. AMPLIFIER THE EMITTER ELECTRODE OF THE D.-C. AMPLIFIER BEING CONNECTED TO THE POSITIVE POLE OF SAID POTENTIAL SOURCE, THE SERIES CONNECTED LAMPS HAVING ONE TERMINAL CONNECTED TO THE NEGATIVE POLE OF SAID POTENTIAL SOURCE AND THE OTHER TERMINAL CONNECTED TO THE COLLECTOR OF THE D.-C. AMPLIFIER, THE RESISTANCE OF THE LIGHT SENSITIVE RESISTOR VARYING IN RESPONSE TO THE ILLUMINATION INTENSITY OF THE LAMPS WHEREBY THE DEGREE OF NEGATIVE FEEDBACK IS CONTROLLED IN PROPORTION TO THE SIGNAL OUTPUT LEVEL OF THE AMPLIFIER AND CONTROL RESPONSE TIME MEANS FOR THE D.-C. AMPLIFIER.